WO2025054449A1

WO2025054449A1 - Composite polymeric materials, and products and methods of preparing the same

Info

Publication number: WO2025054449A1
Application number: PCT/US2024/045580
Authority: WO
Inventors: Enrico Mortarino; Joshua Davis; Murat TONGA; Lam Tran; Seth Sharber; Vivian CHAN; Thien An Phung HAI
Original assignee: Evolved by Nature Inc
Current assignee: Evolved by Nature Inc
Priority date: 2023-09-06
Filing date: 2024-09-06
Publication date: 2025-03-13
Anticipated expiration: 2026-03-06
Also published as: TW202528611A

Abstract

The disclosure provides leather articles having composite layer coatings including optional mechanically engineered topographical features.

Description

COMPOSITE POLYMERIC MATERIALS, AND PRODUCTS AND METHODS OF PREPARING THE SAME FIELD The disclosure relates to composite polymeric materials, including in part a cellulose- derivative coating composition, optionally including silk fibroin proteins or fragments thereof and various additional agents, for coating various substrates. BACKGROUND Silk is a natural polymer produced by a variety of insects and spiders, and comprises a filament core protein, silk fibroin, and a glue-like coating consisting of a non-filamentous protein, sericin. Silk fibers are lightweight, breathable, and hypoallergenic. SUMMARY Embodiments of the present disclosure provide a composite comprising a first polymeric macromolecular species or polymer and a second polymeric macromolecular species or polymer. In some embodiments, a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer are physically and/or chemically entangled. In some embodiments, a portion of the first polymeric macromolecular species or polymer are physically and/or chemically crosslinked. In some embodiments, a portion of the second polymeric macromolecular species or polymer are physically and/or chemically crosslinked. In some embodiments, a portion of the first polymeric macromolecular species or polymer are chemically and/or physically integrated into a portion of the second polymeric macromolecular species or polymer. In some embodiments, a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer are not separable. In some embodiments, a portion of the first polymeric macromolecular species or polymer and/or a portion of the second polymeric macromolecular species or polymer are cross-linked. In some embodiments, a portion of the first polymeric macromolecular species or polymer and/or a portion of the second polymeric macromolecular species or polymer are partially organized and/or crystallized. In some embodiments, a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer cannot be delaminated. In some embodiments, a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer are self-assembled. In some embodiments, a portion of the first polymeric macromolecular species or polymer in the composite has a second structure different than a first structure of the first polymeric macromolecular species or polymer. In some embodiments, a portion of the second polymeric macromolecular species or polymer in the composite has a second structure different than a first structure of the second polymeric macromolecular species or polymer. In some embodiments, a portion of the first polymeric macromolecular species or polymer in the composite has a second structure different than a first structure of the first polymeric macromolecular species or polymer, and a portion of the second polymeric macromolecular species or polymer in the composite has a second structure different than a first structure of the second polymeric macromolecular species or polymer. In some embodiments, the first polymeric macromolecular species or polymer comprises a protein component. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the first polymeric macromolecular species or polymer comprises a biodegradable polymer. In some embodiments, the first polymeric macromolecular species or polymer comprises one or more of a polyurethane component. In some embodiments, the first polymeric macromolecular species or polymer comprises a poly lactic acid (PLA) component, a poly(lactic-co-glycolic acid) (PLGA) component, or both. In some embodiments, the second polymeric macromolecular species or polymer comprises a cellulose and/or cellulose derivative component. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 5% and less than about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 10% and about 20%, between about 20% and about 30%, between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%, less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%, less than about 84%, less than about 83%, less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%, less than about 71%, less than about 70%, less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%, less than about 32%, less than about 31%, less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%. In some embodiments, the w/w ratio between the first polymeric macromolecular species or polymer and the second polymeric macromolecular species polymer in the composite is between about 1:100 and about 100:1. In some embodiments, the w/w ratio between the first polymeric macromolecular species or polymer and the second polymeric macromolecular species polymer in the composite is about 99:1, about 98:2, about 97:3, about 96:4, about 95:5, about 94:6, about 93:7, about 92:8, about 91:9, about 90:10, about 89:11, about 88:12, about 87:13, about 86:14, about 85:15, about 84:16, about 83:17, about 82:18, about 81:19, about 80:20, about 79:21, about 78:22, about 77:23, about 76:24, about 75:25, about 74:26, about 73:27, about 72:28, about 71:29, about 70:30, about 69:31, about 68:32, about 67:33, about 66:34, about 65:35, about 64:36, about 63:37, about 62:38, about 61:39, about 60:40, about 59:41, about 58:42, about 57:43, about 56:44, about 55:45, about 54:46, about 53:47, about 52:48, about 51:49, about 50:50, about 49:51, about 48:52, about 47:53, about 46:54, about 45:55, about 44:56, about 43:57, about 42:58, about 41:59, about 40:60, about 39:61, about 38:62, about 37:63, about 36:64, about 35:65, about 34:66, about 33:67, about 32:68, about 31:69, about 30:70, about 29:71, about 28:72, about 27:73, about 26:74, about 25:75, about 24:76, about 23:77, about 22:78, about 21:79, about 20:80, about 19:81, about 18:82, about 17:83, about 16:84, about 15:85, about 14:86, about 13:87, about 12:88, about 11:89, about 10:90, about 9:91, about 8:92, about 7:93, about 6:94, about 5:95, about 4:96, about 3:97, about 2:98, or about 1:99. In some embodiments, the w/w ratio between the first polymeric macromolecular species or polymer and the second polymeric macromolecular species polymer in the composite is about 10:1, about 10:2, about 10:3, about 10:4, about 10:5, about 10:6, about 10:7, about 10:8, about 10:9, or about 10:10. In some embodiments, the first polymeric macromolecular species or polymer is distributed isotropically over a cross section of the composite. In some embodiments, the first polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite. In some embodiments, a concentration of the first polymeric macromolecular species or polymer closer to a first surface of the composite is higher than a concentration of the first polymeric macromolecular species or polymer closer to a second surface of the composite. In some embodiments, the first polymeric macromolecular species or polymer is substantially undetectable at a second surface of the composite. In some embodiments, the second polymeric macromolecular species or polymer is distributed isotropically over a cross section of the composite. In some embodiments, the second polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite. In some embodiments, a concentration of the second polymeric macromolecular species or polymer closer to a second surface of the composite is higher than a concentration of the second polymeric macromolecular species or polymer closer to a first surface of the composite. In some embodiments, the second polymeric macromolecular species or polymer is substantially undetectable at a first surface of the composite substrate-coating interface. In some embodiments, a first surface of the composite is adhesive. In some embodiments, a second surface of the composite is adhesive. In some embodiments, a first surface of the composite is adhesive, and a second surface of the composite is adhesive. In some embodiments, a first surface of the composite is adhesive, and a second surface of the composite is non-adhesive. In some embodiments, the composite has an increased water resistance compared to one of: i) a non-composite material comprising the first polymeric macromolecular species or polymer, but excluding the second polymeric macromolecular species or polymer, ii) a non-composite material comprising the second polymeric macromolecular species or polymer, but excluding the first polymeric macromolecular species or polymer, or iii) a non-composite material comprising the first polymeric macromolecular species or polymer and the second polymeric macromolecular species or polymer, wherein the polymeric macromolecular species or polymers are not physically and/or chemically molecularly entangled. In some embodiments, the composite has an increased water vapor permeability compared to one of: i) a non-composite material comprising the first polymeric macromolecular species or polymer, but excluding the second polymeric macromolecular species or polymer, ii) a non-composite material comprising the second polymeric macromolecular species or polymer, but excluding the first polymeric macromolecular species or polymer, or iii) a non-composite material comprising the first polymeric macromolecular species or polymer and the second polymeric macromolecular species or polymer, wherein the polymeric macromolecular species or polymers are not physically and/or chemically molecularly entangled. Embodiments of the present disclosure provide an article comprising a substrate and a coating, the coating comprising the composite as described in any of the embodiments above. In some embodiments, the substrate comprises an irregular surface. In some embodiments, the coating has a thickness between about 10 µm and about 1000 µm. In some embodiments, the amount of coating on the substrate is between about 0.01 g/ft² and about 25 g/ft². In some embodiments, the amount of first polymeric macromolecular species or polymer in the coating on the substrate is between about 0.001 g/ft² and about 20 g/ft². In some embodiments, the amount of second polymeric macromolecular species or polymer in the coating on the substrate is between about 0.001 g/ft² and about 15 g/ft². In some embodiments, the substrate comprises a substantially flexible material. In some embodiments, the substrate comprises a leather material or a textile material. In some embodiments, the substrate comprises one or more of collagen, cellulose, and/or lignin. Embodiments of the present disclosure provide a method of coating a substrate, the method comprising applying to a surface of the substrate a first composition comprising a first polymeric macromolecular species or polymer, and a second composition comprising a second polymeric macromolecular species or polymer. In some embodiments, the first composition comprises an unstructured first polymeric macromolecular species or polymer, or a first structure of the first polymeric macromolecular species or polymer. In some embodiments, the first polymeric macromolecular species or polymer comprises a protein component. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the first polymeric macromolecular species or polymer comprises a biodegradable polymer. In some embodiments, the first polymeric macromolecular species or polymer comprises one or more of a polyurethane component. In some embodiments, the first polymeric macromolecular species or polymer comprises a poly lactic acid (PLA) component, a poly(lactic-co-glycolic acid) (PLGA) component, or both. In some embodiments, the second composition comprises an unstructured second polymeric macromolecular species or polymer, or a first structure of the second polymeric macromolecular species or polymer. In some embodiments, the second polymeric macromolecular species or polymer comprises a cellulose and/or cellulose derivative component. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, the cellulose derivative comprises a first structure of the cellulose derivative having a degree of crystallinity lower than a second structure of the cellulose derivative comprising a degree of crystallinity of between about 5% and less than about 100%. In some embodiments, the second composition comprising a second polymeric macromolecular species or polymer further comprises a solvent component. In some embodiments, the solvent component comprises an alcohol and/or an alcohol derivative. In some embodiments, the solvent component comprises one or more of an alcohol, an ether, a ketone, an aldehyde, and/or a ketal. In some embodiments, the solvent component is from about 75% w/w to about 99% w/w of the composition, from about 80% w/w to about 98% w/w of the composition, from about 85% w/w to about 97.5% w/w of the composition, or from about 85% w/w to about 95% w/w of the composition. In some embodiments, the solvent component comprises one or more of methanol, ethanol, n- propanol, 2-propanol, n-butanol, 2-butanol, pentanol, hexanol, acetone, butanone, methoxypropanol, di-isopropylidene glycerol, 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane-4-methanol, or any combination thereof. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer further comprises one or more of a polyethylene glycol (PEG) component, a polypropylene glycol (PPG) component, and/or a polyether component. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer further comprises one or more of fatty acid or fatty acid derived amide, and/or a monoglyceride, diglyceride, and/or triglyceride. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer further comprises one or more of a triethylene glycol monomethyl ether component, a diethylene glycol butyl ether component, a diethylene glycol ethyl ether component, a dimethyl tetradecanedioate component, an erucamide component, and/or a glyceryl stearate component. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer comprises one or more of an isocyanate component, a polyol component, a blocked isocyanate component, and/or a blocked polyol component. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer comprises a partially polymerized, partially crosslinked, and/or partially cured polyurethane component. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer further comprises a polyurethane prepolymer component. In some embodiments, a first composition comprising a first polymeric macromolecular species or polymer further comprises water. In some embodiments, a surface of the substrate is coated first with the first composition comprising a first polymeric macromolecular species or polymer, and the coated with the second composition comprising a second polymeric macromolecular species or polymer. In some embodiments, the method further comprises a drying or partial drying step between the two coating steps. In some embodiments, the first composition comprising a first polymeric macromolecular species or polymer is only partially polymerized, partially dried, and/or partially cured before the second composition comprising a second polymeric macromolecular species or polymer is applied. In some embodiments, the second composition comprising a second polymeric macromolecular species or polymer is applied at a temperature above a glass transition temperature (T_g) of the first polymeric macromolecular species or polymer. In some embodiments, the second composition comprising a second polymeric macromolecular species or polymer is applied at a temperature above a glass transition temperature (Tg) of the second polymeric macromolecular species or polymer. In some embodiments, the first composition comprising a first polymeric macromolecular species or polymer is applied one or more times at a rate from about 0.5 mL/ft² to about 5 mL/ft². In some embodiments, the second composition comprising a second polymeric macromolecular species or polymer is applied one or more times at a rate from about 0.5 mL/ft² to about 5 mL/ft². Embodiments of the present disclosure provide an article comprising a substrate and a coating, the article made by a method as described in any of the embodiments above. In some embodiments, the first polymeric macromolecular species or polymer is distributed isotropically over a cross section of the coating from a substrate-coating interface to an external surface of the coating. In some embodiments, the first polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the coating from a substrate-coating interface to an external surface of the coating. In some embodiments, a concentration of the first polymeric macromolecular species or polymer closer to a substrate- coating interface is higher than a concentration of the first macromolecular species or polymer closer to an external surface of the coating. In some embodiments, the first polymeric macromolecular species or polymer is substantially undetectable at an external surface of the coating. In some embodiments, the second polymeric macromolecular species or polymer is distributed isotropically over a cross section of the coating from a substrate- coating interface to an external surface of the coating. In some embodiments, the second polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the coating from a substrate-coating interface to an external surface of the coating. In some embodiments, a concentration of the second polymeric macromolecular species or polymer closer to a substrate-coating interface is lower than a concentration of the second polymeric macromolecular species or polymer closer to an external surface of the coating. In some embodiments, the second polymeric macromolecular species or polymer is substantially undetectable at a substrate-coating interface. Embodiments of the present disclosure provide a composite of any one of the preceding embodiments, or a method of making thereof, comprising a mattifying agent and/or a plasticizer described herein. Embodiments of the present disclosure provide an article of any one of the preceding embodiments, or a method of making thereof, comprising a mattifying agent and/or a plasticizer described herein. Embodiments of the present disclosure provide composite or an article of any one of the preceding claims, or a method of making thereof, comprising modified fibroin fragments described herein. Embodiments of the present disclosure provide a plurality of fibroin fragments are modified, each comprising one or more amino acid residue modifications selected from an asparagine to aspartic acid modification, a glutamine to glutamic acid modification, and a methionine to methionine oxide modification. Embodiments of the present disclosure provide a plurality of modified fibroin fragment comprises one modification. Embodiments of the present disclosure provide a plurality of modified fibroin fragment comprises two modifications. Embodiments of the present disclosure provide a plurality of modified fibroin fragment comprises three modifications. Embodiments of the present disclosure provide an asparagine to aspartic acid modification is at one or more positions selected from N23, N28, N108, N118, N136, N186, N200, N204, N240, N248, N68, N70, N77, N5262, N93, N132, N149, N172, N174, N202, N105, N4191, Embodiments of the present disclosure provide a glutamine to glutamic acid modification is at one or more positions selected from Q24, Q149, Q202, Q58, Q139, Q275, Q5216, Q255, and Q125. Embodiments of the present disclosure provide a methionine to methionine oxide modification is at the M64 position. Embodiments of the present disclosure provide each modification is independently ranging in the composition between about 1% to about 99%. Embodiments of the present disclosure provide a % modification is defined as (number of modified fibroin fragments having a modification at a specific position divided by the total number of modified fibroin fragments which include the specific position, modified or unmodified) x 100. Embodiments of the present disclosure provide a coating system for coating a leather article comprising a basecoat layer comprising one or more of a polyurethane dispersion (PUD), a protein component, and a solvent, and a topcoat layer comprising one or more of a polyurethane dispersion (PUD), a cellulose derivative, an alcohol solvent, and a glycerin derivative. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 5% and less than about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 10% and about 20%, between about 20% and about 30%, between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%, less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%, less than about 84%, less than about 83%, less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%, less than about 71%, less than about 70%, less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%, less than about 32%, less than about 31%, less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the alcohol solvent is methanol, ethanol, acetone, isopropanol, n-Butanol, or a combination thereof. In some embodiments, the coating has a thickness between about 10 µm and about 1000 µm. In some embodiments, wherein the amount of coating on the substrate is between about 0.01 g/ft2 and about 25 g/ft2. Embodiments of the present disclosure provide a method of coating a leather article, the method comprising applying to a surface of the leather a basecoat layer comprising one or more of a polyurethane dispersion (PUD), a protein component, and a solvent, and a topcoat layer comprising one or more of a polyurethane dispersion (PUD), a cellulose derivative, an alcohol solvent, and a glycerin derivative. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 5% and less than about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of between about 10% and about 20%, between about 20% and about 30%, between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%, less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%, less than about 84%, less than about 83%, less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%, less than about 71%, less than about 70%, less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%, less than about 32%, less than about 31%, less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the alcohol solvent is methanol, ethanol, acetone, isopropanol, n-Butanol, or a combination thereof. In some embodiments, the coating has a thickness between about 10 µm and about 1000 µm. In some embodiments, the amount of coating on the substrate is between about 0.01 g/ft2 and about 25 g/ft2. BRIEF DESCRIPTION OF THE DRAWINGS The presently disclosed embodiments will be further explained with reference to the attached drawings. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments. Figure 1 is a flow chart showing various embodiments for producing pure silk fibroin-based protein fragments (SPFs) of the present disclosure. Figure 2 is a flow chart showing various parameters that can be modified during the process of producing SPFs of the present disclosure during the extraction and the dissolution steps. Figure 3 illustrates general steps used in leather processing. Figure 4 is a photograph of the felt pads (and associated leather samples) after 600 continuous cycles of Wet Veslic Rubbing, comparing silk fibroin fragment compositions (bottom sample – Entry B2) treated leather samples to polyurethane (top 2 samples) treated leather samples. Note the damage to the polyurethane samples and loss of dye from the leather to the felt after 600 cycles). Figure 5 is a photograph of the felt pads after 10 cycles of Wet Veslic Rubbing on Entries A1, A2, B1 and B2 (Table 1) treated leather samples. Figure 6 is a photograph of water droplets placed on samples treated either with silk fibroin fragments or a crosslinked polyurethane coating system after Wet Veslic Rubbing has been performed. In the case of silk fibroin fragments (Entry B2), the sample was exposed to 600 cycles of rubbing whereas the polyurethane samples only endured 10 cycles. The photograph was taken 5 minutes after placing the water droplets. Note the penetration of water into the leather matrix when using the commercial reference systems designed as top- coats. Figure 7A-7B is a graphical analysis illustrating the results of Water Vapor Transmission Test #1 on coated leather (7A) and uncoated leather (7B). Figure 8A-8B is a graphical analysis illustrating the results of Water Vapor Transmission Test #2 on coated leather (8A) and uncoated leather (8B). Figure 9A-9B is a graphical analysis illustrating the results of Water Vapor Transmission Test #3 on coated leather (9A) and uncoated leather (9B). Figure 10 is photographs of uncoated plain leather. Figure 11 show an FTIR analysis of uncoated plain leather. Figure 12 is photographs of leather treated with an adhesive coating of a coating system disclosed herein. Figure 13 shows an FTIR analysis of leather treated with an adhesive coating of a coating system disclosed herein. Figure 14A is photographs of treated leather finished with a top coat of a coating system disclosed herein. Figure 14B shows an FTIR analysis of treated leather finished with a top coat of a coating system disclosed herein. Figure 15A is an IR Spectra of leather samples treated with a coating system disclosed herein by LN-MCT Detector. Figure 15B shows Macro ATR Imaging of a leather sample treated with an adhesive base coat of a coating system disclosed herein. Figure 15C shows Macro ATR Imaging of a leather sample treated with a top coat of a coating system disclosed herein. Figures 16A- 16H are photographs illustrating the results of the soil release test with various stain sources on leather treated with a coating system disclosed herein.16A: Mud, 16B: Water, 16C: Mustard, 16D: Corn Oil, 16E: Wine, 16F: Ketchup, 16G: French Dressing, 16H: Coffee. Figure 17A- 17C are photographs of the leather samples treated with a coating system disclosed herein used in the Industrialization Trial. Figure 18A- 18I are photographs of the felt pads (and associated leather samples treated with a coating system disclosed herein) after 600 continuous cycles of Wet Veslic Rubbing (Note: Fig.18H was only subject to 360 cycles). Figure 19A- 19D are photographs illustrating the results of a Bally Flex Test conducted on various leather samples treated with a coating system disclosed herein. Figure 20A- 20I are photographs illustrating the results of an Adhesive Tape Test conducted on various leather samples treated with an adhesive coating system. Figure 21 is a photograph illustrating the difference between leather samples treated with an adhesive coating system disclosed herein before and after milling. Figures 22A- 22I are photographs illustrating the results of an Adhesive Tape Test conducted on various leather samples treated with an adhesive coating system disclosed herein. Figure 23 is a photograph illustrating the difference between leather samples treated with an adhesive coating system disclosed herein before and after milling. Figure 24A- 24B are photographs illustrating the difference in an Adhesive Tape Test conducted on a leather sample treated with an adhesive coating system disclosed herein before and after milling. Figure 25A- 25C are microscopic cross-sectional images of a leather surface treated with a coating system disclosed herein. Figure 26A- 26C are microscopic top view images of a leather surface treated with a coating system disclosed herein. Figure 27A- 27C are images showing a wet blue leather strip treated with a coating system disclosed herein under a digital microscope.27A: side view, 27B: top grain view, 27C: flesh view. Figure 28A- 28C are images showing a paper strip treated with a coating system disclosed herein under a digital microscope.28A: top view, 28B: side view, 28C: back view. Figure 29A- 29C are images showing a fabric strip treated with a coating system disclosed herein under a digital microscope.29A: top view, 29B: side view, 29C: back view. Figure 30A- 30C are images showing a fabric strip with blue tape treated with a coating system disclosed herein under a digital microscope.30A: top view, 30B: side view, 30C: back view. Figure 31 shows pictures of AS-104 + 2% Glycerol + 50 mM magnesium sulfate films tensile testing process. Figure 32 shows proposed formulation mechanism incorporating AS-104, 2% glycerol and salts at various concentrations. Figure 33A shows elongation at break of AS-104, 2% glycerol and guanidinium hydrochloride (5, 10, 25 and 50 mM). Figure 33B shows ultimate tensile strength of AS-104, 2% glycerol and guanidinium hydrochloride (5, 10, 25 and 50 mM). Figure 34A shows elongation at break of AS-104, 2% glycerol and sodium chloride (5, 10, 25 and 50 mM). Figure 34B shows ultimate tensile strength of AS-104, 2% glycerol and sodium chloride (5, 10, 25 and 50 mM). Figure 35A shows elongation at break of AS-104, 2% glycerol and urea (5, 10, 25 and 50 mM). Figure 35B shows ultimate tensile strength of AS-104, 2% glycerol and urea (5, 10, 25 and 50 mM). Figure 36A shows elongation at break of AS-104, 2% glycerol and L-Arginine hydrochloride (5, 10, 25 and 50 mM). Figure 36B shows ultimate tensile strength of AS-104, 2% glycerol and L-Arginine hydrochloride (5, 10, 25 and 50 mM). Figure 37A shows elongation at break of AS-104, 2% glycerol and magnesium sulfate heptahydrate (5, 10, 25 and 50 mM). Figure 37B shows ultimate tensile strength of AS-104, 2% glycerol and magnesium sulfate heptahydrate (5, 10, 25 and 50 mM). Figure 38A shows elongation at break of AS-104, 2% glycerol and ammonium sulfate (5, 10, 25 and 50 mM). Figure 38B shows ultimate tensile strength of AS-104, 2% glycerol and ammonium sulfate (5, 10, 25 and 50 mM). Figure 39A shows elongation at break of AS-104, 2% glycerol and calcium chloride (5, 10, 25 and 50 mM). Figure 39B shows ultimate tensile strength of AS-104, 2% glycerol and calcium chloride (5, 10, 25 and 50 mM). Figure 40A shows elongation at break of AS-104, 2% glycerol and magnesium chloride (5, 10, 25 and 50 mM). Figure 40B shows ultimate tensile strength of AS-104, 2% glycerol and magnesium chloride (5, 10, 25 and 50 mM). Figure 41A shows elongation at break of AS-104, 2% glycerol and calcium sulfate dihydrate (5, 10, 25 and 50 mM). Figure 41B shows ultimate tensile strength of AS-104, 2% glycerol and calcium sulfate dihydrate (5, 10, 25 and 50 mM). Figure 42A shows elongation at break of AS-104, 2% glycerol and calcium lactobionate (5, 10, 25 and 50 mM). Figure 42B shows ultimate tensile strength of AS-104, 2% glycerol and calcium lactobionate (5, 10, 25 and 50 mM). Figure 43 compiles all data on elongation at break. Figure 44 compiles all data on ultimate tensile strength. Figure 45 shows Veslic wet and dry testing results of Bodin Basic Black leather coated with 17% AS-104-5% Melio-9S11, 17% AS-104-5% Melio-9S11-10 mM CaCl2, 17% AS-104-5% Melio-9S11-50 mM MgSO4 and 17% AS-104-5% Melio-9S11-25 mM L- Arginine hydrochloride Figure 46 shows Veslic wet and dry Testing results of Bodin Brown leather coated with 17% AS-104-5% Melio-9S11, 17% AS-104-5% Melio-9S11-10 mM CaCl2, 17% AS- 104-5% Melio-9S11-50 mM MgSO4 and 17% AS-104-5% Melio-9S11-25 mM L-Arginine hydrochloride Figure 47 shows Veslic scores for Bodin Basic Black leather coated with 17% AS- 104-5% Melio-9S11, 17% AS-104-5% Melio-9S11-10 mM CaCl2, 17% AS-104-5% Melio- 9S11-50 mM MgSO4 and 17% AS-104-5% Melio-9S11-25 mM L-Arginine hydrochloride Figure 48 shows Veslic scores for Bodin Brown leather coated with 17% AS-104-5% Melio-9S11, 17% AS-104-5% Melio-9S11-10 mM CaCl2, 17% AS-104-5% Melio-9S11-50 mM MgSO4 and 17% AS-104-5% Melio-9S11-25 mM L-Arginine hydrochloride Figure 49A and 49B illustrate before and after topography traces of a leather sample coated with GG- silk before (FIG.23A) and after (FIG.23B) coating with Silk + 0.5% wt. GG via point filling. Traces were captured using a Taylor Hobson CCI HD optical profilometer. Figure 50 shows a schematic of the preparation of a 2-part matting agent system. Figure 51A shows gray, brown, and black leathers with CAP-7. Figure 51B shows gray, brown, and black leathers with MHG. Figure 51C shows gray, brown, and black leathers with DPGDB. Figure 52 shows weight of the coated sample versus the diameter of the spray nozzle. Figure 53A shows 2.5% concentration ethyl cellulose in methoxy propanol on leather (not milled crust). Figure 53B shows 2.5% concentration ethyl cellulose in methoxy propanol on milled crust leather. Figure 53C shows 5% concentration ethyl cellulose in methoxy propanol on leather (not milled crust). Figure 53D shows 5% concentration ethyl cellulose in methoxy propanol on milled crust leather. Figure 53E shows 7% concentration ethyl cellulose in methoxy propanol on leather (not milled crust). Figure 53F shows 7% concentration ethyl cellulose in methoxy propanol on milled crust leather. Figure 54 shows test results from Formulation A matte testing. Figure 55A shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55B shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55C shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55D shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55E shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55F shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55G shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A before ironing. Figure 55H shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55I shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55J shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55K shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55L shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55M shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 55N shows samples of Euroleather (top) and Fragopel (bottom) with Formulation A after ironing. Figure 56A shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56B shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56C shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56D shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56E shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56F shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56G shows samples of Fragopel with Formulation A after (top) and before (bottom) milling. Figure 56H shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56I shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56J shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56K shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56L shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56M shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 56N shows samples of Euroleather with Formulation A after (top) and before (bottom) milling. Figure 57A shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D before ironing. Figure 57B shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D before ironing. Figure 57C shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D before ironing. Figure 57D shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D before ironing. Figure 57E shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing. Figure 57F shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing. Figure 57G shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing. Figure 57H shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing. Figure 57I shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing (top) and after milling (bottom). Figure 57J shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing (top) and after milling (bottom). Figure 57K shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing (top) and after milling (bottom). Figure 57L shows samples of Euroleather (left) and Fracopel (right) with Formulations A, B, C, and D after ironing (top) and after milling (bottom). Figure 58A shows a vulcanization test after 2hrs @130C, which passes with a color change of 4/5. Figure 58B shows a sample forgotten in the oven after the vulcanization test overnight, which still passes with a color change of 4/5. Figure 59A shows finishing resistance when handling leather after spraying and before ironing of 072-1. Figure 59B shows finishing resistance when handling leather after spraying and before ironing of 072-2. Figures 59C shows finishing resistance when handling leather after spraying and before ironing of 072-3. Figure 60 shows IR spectra of the samples by LN-MCT detector. Figure 61 shows macro ATR imaging of the sample with an adhesive base coat. Figure 62 shows macro ATR imaging of the sample with the top coat. Figure 63 shows a cross-section of uncoated leather. Unevenness on the surface is visible. Figure 64 shows a cross-section of basecoat coated leather. Figure 65 shows coated leather with L1 system. Figure 66 shows further magnification of silver tagged silk in L1 system. Basecoat/topcoat composite indicated by silver tagged silk throughout the coating. Figure 67 shows a schematic of the layers formed. Figure 68. Ion Exchange Fractionation Schemes for the isolation of the populations that constitute Low and Mid Skid silk/modified polypeptide compositions. Low and Mid Skid silk/modified polypeptide compositions contains silk/modified polypeptides that are negatively, positively charged, or neutral. Using Q anion exchange chromatography (A) these populations were isolated. Figure 69. Chromatogram of Low Skid silk/modified polypeptide composition loaded in a Q-Sepharose HP column (Cytiva). The flow through contains the silk/modified polypeptides that do not get captured in the column and are the depleted in negatively charged amino acids. After the column is loaded with Low or Mid Skid silk/modified polypeptide compositions and the flow through is collected, the column is washed until the UV-280 absorbance becomes less than 200 AU. The captured negatively charged silk/modified polypeptides are eluted with high salt concentration (1M NaCl) and constitute AS11 and AS22. The chromatography is performed in Tris-containing buffers but the flow through and the Q-elution were finally dialyzed in water. Figure 70. Analytical Size Exclusion Chromatography of Low, Mid Skid silk/modified silk compositions and their constituent AS compositions. Average molecular weight in kDa and polydispersity measurements are shown. Figure 71. Analytical Size Exclusion Chromatography of the Low and Mid skid silk/modified peptide compositions and their components (see table 80 for more details). A, Molecular weight of the various Activated Silk new compositions described in this study. B, Polydispersity (PDI) of the various Activated Silk new compositions described in this study. AS24 reconstitutes the average molecular weight and polydispersity of the Low skid silk/modified peptide composition and it consists of 50% AS12 and 50% AS22 (see table 80 for details). AS6 reconstitutes the average molecular weight and polydispersity of the Mid skid silk/modified peptide composition and it consists of 50% AS1 and 50% AS11 (see table 80 for details). Figure 72. Isoelectric Focusing Electrophoresis of Low Skid silk/modified polypeptide compositions. Lanes 2, 7; Low Skid silk different amounts loaded. Lanes 3, 5, 8, 10; AS12 silk, different preparations different amounts loaded. Lanes 4, 6, 9, 11; AS22 silk, different preparations different amounts loaded. Figure 73. Self-assembly reactions of the of the Low and Mid skid silk/modified peptide compositions and their components (see table 80 for more details). Both graphs depict the kinetic parameters of gel formation during self-assembly of silk. On graph A calculation of the three self-assembly kinetic parameters is shown, t0.5, Amax and SARF. For more details look at the text. Figure 74. Self-assembly kinetics of the Low and Mid skid silk/modified peptide compositions and their components (see table 80 for more details). A, the Self-assembly Rate Factor shows how fast the self-assembly reaction proceeds once it is initiated and the self- assembly nuclei are organized. B, Maximum Gel Yield shows how dense the silk gel is after self-assembly is complete. C, Time required for the self-assembly reaction to produce half of the maximum gel amount. Figure 75. the Low and Mid skid silk/modified peptide compositions and their components (see table 80 for more details). The Self Assembly Factor reflects the average propensity of silk to self-assemble and form gels. While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments. Figure 76 is a graph of molecular weight plotted as a function of time for solubilized fibroin in 9.3 M LiBr at 100° C - 103° C. Figure 77 is a graph of molecular weight plotted as a function of time for solubilized fibroin in 9.3 M LiBr at 122° C - 125° C. Figure 78 is a graph illustrating percentage of amino acid modification in silk. Figures 79A-79C are graphs illustrating percentage of amino acid modifications in Low and Mid Skid silk. Fig.79A illustrates heavy chain modifications, Fig.79B illustrates light chain modifications, and Fig.79C illustrates fibrohexamerin modifications. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Figures 80A- 80B are graphs illustrating percentage of amino acid modifications in Low and Mid Skid silk produced and lyophilized. Fig.80A illustrates heavy chain modifications and Fig.80B illustrates light chain modifications. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Figures 81A- 81B are graphs illustrating percentage of amino acid modifications in Low Skid silk produced in two different facilities. Fig.81A illustrates heavy chain modifications and Fig.81B illustrates light chain modifications. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Figure 82 are graphs illustrating percentage of amino acid modifications in Mid silk produced in Skid and Benchtop scale. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Figure 83 is an explanation of the method used to calculate percentage ratios of modified amino acids at specific locations along the sequence of each peptide. Figure 84 illustrates an Anion exchange chromatography and size exclusion chromatography scheme of the isolation of Low Skid silk/modified peptide compositions. Low Skid silk/modified polypeptide compositions is composed of a variety of peptide populations, in a wide range of sizes and charge. Using Q-Sepharose anion exchange chromatography as a first step, and HiLoad Superdex 200 size exclusion chromatography as a second purification step, distinct populations of Low Skid silk/modified polypeptide compositions were separated. The Q-Sepharose eluate was loaded onto HiLoad Superdex 200 size exclusion chromatography, which resulted in negatively charged silk compositions/modified peptides fractionated by size. Figures 85A and 85B are chromatograms of the anion exchange chromatography and the following size exclusion chromatography of the eluate (Q-eluate) of Low Skid silk/modified polypeptide compositions. Fig.85A: Anion exchange chromatography was performed with a Q-Sepharose column. Low Skid silk/modified peptide compositions were separated to uncharged peptide population (flowthrough – light blue background) and eluted negatively charged silk compositions (eluate – light pink background) by anion exchange chromatography. Light yellow background indicates column wash with 50 mM Tris pH=8.0 before eluting the charged peptide population. Fig.85B: The negatively charged eluate was loaded onto the Superdex 200 column and was flowed through the column with 50 mM Tris, 200 mM CaCl2, pH=8.0. When the UV-280 absorbance started to increase fractions were collected to separate the Low Skid silk/modified peptide compositions by size. The relative elution volume of silk compositions AS77 and AS81 are indicated on the chromatogram. Figures 86A and 86B illustrates the Analytical Size Exclusion Chromatography of Low Skid silk/modified silk compositions and their constituent AS compositions. Fig.86A. Average molecular weight in kDa of Low Skid silk (LS) and AS77-AS81 are shown. Fig. 86B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 86. Figure 87 is a SDS polyacrylamide gel electrophoresis of Low Skid silk/modified polypeptide compositions. Lanes are indicated by fraction number, at the order of elution from the Superdex 200 column, and their respective silk composition: fraction 6 is AS77, fraction 7 is AS78, fraction 8 is AS79, fraction 9 is AS80, and fraction 10 is AS81. Figures 88A and 88B are graphs illustrating self-assembly reactions of the of the Low Skid silk/modified peptide compositions. Mid Skid Silk reaction was used as a positive control. Fig.88A. Illustrate kinetic parameters of gel formation during self-assembly of silk. Self-Assembly parameters of Mid Skid silk: Amax is 0.6780 (Abs), SARF is 8.676, T0.5 is 3.668 h, and the FSAF is 3.08 (Abs/min). Fig.88B. Is a snapshot of a later time point of the same self-assembly assay, 12 days after setting the assay. None of the tested fraction has self-assembled over time. Figures 89A and 89B illustrate the characterization of Low Skid silk compositions by Dynamic Light Scattering. Low skid silk/modified peptide compositions were diluted to a concentration of 1 mg/mL, filtered, and analyzed by the Zetasizer Pro to estimate the diameter particle size of each silk composition. Fig.89A. Illustrates intensity diameter particle size distribution measured for silk compositions AS77, AS78, AS79, AS80, and AS81. Fig.9B. Illustrate correlogram functions of silk compositions AS77, AS78, AS79, AS80, AS81. Figure 90 illustrates size exclusion chromatography scheme of the isolation of Low Skid silk/modified peptide compositions. Low Skid silk/modified polypeptide compositions is composed of a variety of peptide populations, in a wide range of sizes, using HiLoad Superdex 200 size exclusion chromatography, distinct populations of Low Skid silk/modified polypeptide compositions were separated. Figure 91 is a chromatogram of Low Skid silk/modified polypeptide compositions loaded onto a Superdex 200 gel filtration column. Low Skid silk/modified peptide compositions were loaded onto the Superdex 200 column and were flowed through the column with 50 mM Tris, 200 mM CaCl2, pH=8.0. When the UV-280 absorbance started to increase fractions were collected to separate the Low Skid silk/modified peptide compositions by size. The relative elution volume of silk compositions AS82, AS86, and AS87 are indicated on the chromatogram. Figures 92A and 92B illustrate Analytical Size Exclusion Chromatography of Low Skid silk/modified silk compositions and their constituent AS compositions. Fig.92A. Illustrates average molecular weight in kDa of Low Skid silk (LS) and AS82-AS89 are shown. Fig.92B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 88. Figure 93 is an SDS polyacrylamide gel electrophoresis of Low Skid silk/modified polypeptide compositions. Lanes are indicated by fraction number, at the order of elution from the Superdex 200 column, and their respective silk composition: fraction 6 is AS82, fraction 7 is AS83, fraction 8 is AS84, fraction 9 is AS85, and fraction 10 is AS86. Figures 94A and 94B are graphs illustrating self-assembly reactions of the of the Low Skid silk/modified peptide compositions. Mid Skid Silk reaction was used as a positive control. Fig.94A. Illustrates kinetic parameters of gel formation during self-assembly of silk. Self-Assembly parameters of Mid Skid silk: Amax is 0.6978 (Abs), SARF is 8.591, T0.5 is 3.361 h, and the FSAF is 3.46 (Abs/min). Fig.94B. Is a snapshot of a later time point of the same self-assembly assay, 18 days after setting the assay. AS87, AS88, and AS89 demonstrate gel formation at this time point, that was already observed five days post assay (LS, Low Skid silk; MS, Mid Skid silk). Figures 95A- 5C are graphs showing characterization of Low Skid silk compositions by Dynamic Light Scattering. Low skid silk/modified peptide compositions were diluted to a concentration of 1 mg/mL, filtered, and analyzed by the Zetasizer Pro to estimate particle size of each silk composition. Fig.95A. Shows intensity particle size distribution measured for silk compositions AS82, AS83, AS84, AS85, AS86, AS87, AS88, and AS89. Fig.95B. Shows intensity particle size distribution measured for silk compositions AS82, Low Skid silk/modified peptide compositions (LS), and Mid Skid silk/modified peptide compositions (MS). Fig.95C. Shows correlogram functions of silk compositions AS82, AS83, AS84, AS85, AS86, AS87, AS88, AS89, Low Skid silk/modified peptide compositions (LS), Mid Skid silk/modified peptide compositions (MS). Figure 96 illustrates anion exchange chromatography (Q), hydrophobic interaction chromatography (HIC), and size exclusion chromatography (SEC) scheme of the isolation of Low Skid silk/modified peptide compositions. Low Skid silk/modified polypeptide compositions is composed of a variety of peptide populations, in a wide range of sizes and charge. Using Q-Sepharose anion exchange chromatography as a first step, Butyl ImpRes Hydrophobic interactions resin as a second step, and HiLoad Superdex 200 size exclusion chromatography as a third purification step, distinct populations of Low Skid silk/modified polypeptide compositions were isolated. The Q-Sepharose eluate was loaded onto a Butyl ImpRes (HIC) column, and the HIC-eluate was loaded onto a HiLoad Superdex 200 size exclusion chromatography, which resulted in fractionation of negatively charged silk compositions/modified peptides with hydrophobicity characteristics fractionated by size. The Q-Sepharose eluate contained negatively charged peptides in all sizes. Resolving these peptides by Butyl ImpRes column resulted in elution of high-molecular-weight, negatively charged, somewhat hydrophobic silk compositions/modified peptides. The smaller negatively charged peptides were washed as flowthrough and did not bind the Butyl ImpRes column. The Q-HIC(elution) was loaded into Superdex 200 and was separated by size. Figures 97A- 97E are chromatograms of anion exchange chromatography, hydrophobic interactions chromatography, and the following size exclusion chromatography of Low Skid silk/modified polypeptide compositions. Fig.97A. illustrates anion exchange chromatography was performed with a Q-Sepharose column. Low Skid silk/modified peptide compositions were separated to uncharged peptide population (flowthrough – light blue background) and eluted negatively charged silk compositions (eluate – light pink background) by anion exchange chromatography. Light yellow background indicates column wash with 50 mM Tris pH=8.0 before eluting the charged peptide population. Fig.97B. illustrates the negatively charged eluate (Q-elution) was loaded onto a Butyl ImpRes column, in the presence of 300 mM ammonium sulfate [(NH4)2SO4], to expose hydrophobic domains of the silk peptides, which allows binding to the column. The highly charged peptide population did not bind the column (flowthrough), highlighted in light blue. The column was washed until OD280 was reduced to ~100 units (light yellow). Then, the bound silk peptides (Q-HIC(elution)) were eluted by using 50 mM Tris, pH=8.0 without ammonium sulfate (light pink). Fig.97C. illustrates the Q-HIC(elution) was further fractionated by size exclusion chromatography (SEC), using the gel filtration column Superdex 200. The Q-HIC(elution) fraction was flowed through the column with 50 mM Tris, 200 mM CaCl2, pH=8.0. When the UV-280 absorbance started to increase fractions were collected to separate the Low Skid silk/modified peptide compositions by size. The relative elution volume of silk compositions AS90 and AS94 are indicated on the chromatogram. Fig.97D. the Q-HIC(flowthrough) fraction was further fractionated by SEC, using the Superdex 200 column, at the same procedure as in (VC). The relative elution volume of silk compositions AS95 and AS100 are indicated on the chromatogram. Fig.97E. illustrates the superimposition of chromatograms (VC) and (VD). the Q-HIC(elution) fraction has a higher-molecular-weight range compared to the Q-HIC(flowthrough) fractions, which elutes later in SEC, and has lower-molecular- weight range. Figures 98A- 98B are graphs showing analytical Size Exclusion Chromatography of Low Skid silk/modified silk compositions and their constituent AS compositions. Fig.98A. Average molecular weight in kDa of Low Skid silk (LS) and AS90-AS100 are shown. Fig.98B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 90 Figures 99A- 99B are SDS polyacrylamide gel electrophoresis of Low Skid silk/modified polypeptide compositions. Fig.99A. Q-HIC(elution) SEC fractions. Fig.99B. Q-HIC(flowthrough) SEC fractions. Lanes are indicated by fraction number, at the order of elution from the Superdex 200 column, and their respective silk composition: in Fig.99A, fraction 6 is AS90, fraction 7 is AS91, fraction 8 is AS92, fraction 9 is AS93, and fraction 10 is AS94. In Fig.99B, fraction 8 is AS95, fraction 9 is AS96, fraction 10 is AS97, fraction 11 is AS98, fraction 12 is AS99, and fraction 13 is AS100. Figure 100 illustrates self-assembly reactions of the of the Low Skid silk/modified peptide compositions. Mid Skid Silk reaction was used as a positive control. kinetic parameters of gel formation during self-assembly of silk. Q-HIC(elution) is the elution fraction that was eluted from the Butyl ImpRes column, prior to SEC purification; LS, Low Skid silk; MS, Mid Skid silk. Self-Assembly parameters of Mid Skid silk: Amax is 0.6974 (Abs), SARF is 8.661, T0.5 is 3.834 h, and the FSAF is 3.03 (Abs/min). Figures 101A- 101F illustrate the characterization of Low Skid silk compositions by Dynamic Light Scattering. Low and Mid skid silk/modified peptide compositions were diluted to a concentration of 1 mg/mL, filtered, and analyzed by the Zetasizer Pro to estimate the diameter particle size of each silk composition. Fig.101A. Intensity diameter particle size distribution measured for silk compositions AS90, Q-HIC(elution) fraction (prior to fractionation by SEC), Low Skid silk (LS), and Mid Skid silk (MS). Fig.101B. Correlogram functions of silk compositions presented in (ZA). Fig. ZC. Intensity diameter particle size distribution measured for silk compositions AS90-AS94, derived from Q-HIC(elution)-SEC fractionation process. Fig.101D. Correlogram functions of silk compositions presented in (ZC). Fig.101E. Intensity diameter particle size distribution measured for silk compositions AS95-AS100, derived from Q-HIC(flowthrough)-SEC fractionation process. Fig.101F. Correlogram functions of silk compositions presented in (ZE). Figure 102. illustrates size exclusion chromatography scheme of the isolation of Mid Skid silk/modified peptide compositions. Mid Skid silk/modified polypeptide compositions is composed of a variety of peptide populations, in a wide range of sizes, using HiLoad Superdex 200 size exclusion chromatography, distinct populations of Mid Skid silk/modified polypeptide compositions were able to be separated. Figure 103. Is a chromatogram of Mid Skid silk/modified polypeptide compositions loaded onto a Superdex 200 gel filtration column. Mid Skid silk/modified peptide compositions were loaded onto the Superdex 200 column and were flowed through the column with 50 mM Tris, 200 mM CaCl2, pH=8.0. When the UV-280 absorbance started to increase fractions were collected to separate the Mid Skid silk/modified peptide compositions by size. The relative elution volume of silk compositions AS107 and AS111 are indicated on the chromatogram. Figure 104A-104B. Illustrates analytical Size Exclusion Chromatography of Mid Skid silk/modified silk compositions and their constituent AS compositions. Fig.104A. Average molecular weight in kDa of Mid Skid silk (MS) and AS106-AS111 are shown. Fig. 104B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 92. Figure 105. Is a SDS polyacrylamide gel electrophoresis of Mid Skid silk/modified polypeptide compositions. Lanes are indicated by fraction number, at the order of elution from the Superdex 200 column, and their respective silk composition: fraction 6 is AS107, fraction 7 is AS108, fraction 8 is AS109, fraction 9 is AS110, and fraction 10 is AS111. Figure 106. Illustrates self-assembly reactions of the of the Mid Skid silk/modified peptide compositions. kinetic parameters of gel formation during self-assembly of silk. Dashed red lines show how the self-assembly parameters Amax, SARF, and T0.5 were calculated for unfractionated Mid Skid silk (MS). These numerical calculated parameters of silk compositions AS106-AS111 can be found in Table 93. Low Skid silk (LS) was used as a negative control. LS, Low Skid silk; MS, Mid Skid silk. Figures 107A-107B. Illustrates characterization of Mid Skid silk compositions by Dynamic Light Scattering. Mid skid silk/modified peptide compositions were diluted to a concentration of 1 mg/mL, filtered, and analyzed by the Zetasizer Pro to estimate particle size of each silk composition. Fig.107A. Intensity particle size distribution measured for silk compositions AS106, AS107, AS108, AS109, AS110, AS111, and Mid Skid (MS). Fig. 107B. Correlation functions of silk compositions presented in (A). Figure 108. Illustrates anion exchange chromatography and size exclusion chromatography scheme of the isolation of Mid Skid silk/modified peptide compositions. Mid Skid silk/modified polypeptide compositions is composed of a variety of peptide populations, in a wide range of sizes and charge. Using Q-Sepharose anion exchange chromatography as a first step, and HiLoad Superdex 200 size exclusion chromatography as a second purification step, distinct populations of Mid Skid silk/modified polypeptide compositions were separated. The Q-Sepharose eluate was loaded onto HiLoad Superdex 200 size exclusion chromatography, which resulted in negatively charged silk compositions/modified peptides fractionated by size. Figures 109A-109B. Are chromatograms of the anion exchange chromatography and the following size exclusion chromatography of the eluate (Q-eluate) of Mid Skid silk/modified polypeptide compositions. Fig.109A. Anion exchange chromatography was performed with a Q-Sepharose column (Cytiva). Mid Skid silk/modified peptide compositions were separated to uncharged peptide population (flowthrough – light blue background) and eluted negatively charged silk compositions (eluate – light pink background) by anion exchange chromatography. Light yellow background indicates column wash with 50 mM Tris pH=8.0 before eluting the charged peptide population. Fig.109B. The negatively charged eluate (Q-elution) was loaded onto the Superdex 200 column and was flowed through the column with 50 mM Tris, 200 mM CaCl2, pH=8.0. When the UV-280 absorbance started to increase fractions were collected to separate the Mid Skid silk/modified peptide compositions by size. The relative elution volume of silk compositions AS101 and AS105 are indicated on the chromatogram. Figures 110A-110B. Illustrate analytical Size Exclusion Chromatography of Mid Skid silk/modified silk compositions and their constituent AS compositions. Fig.110A. Average molecular weight in kDa of Mid Skid silk (MS) and AS101-AS105 are shown. Fig. 110B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 95. Figure 111. Is a SDS polyacrylamide gel electrophoresis of Mid Skid silk/modified polypeptide compositions. Lanes are indicated by fraction number, at the order of elution from the Superdex 200 column, and their respective silk composition: fraction 6 is AS101, fraction 7 is AS102, fraction 8 is AS103, fraction 9 is AS104, and fraction 10 is AS105. Figure 112 illustrates self-assembly reactions of the of the Mid Skid silk/modified peptide compositions. Low Skid Silk reaction was used as a negative control. Kinetic parameters of gel formation during self-assembly of silk are shown. Red dotted lines are shown to clarify the calculations of Amax, SARF (Self-Assembly Rate Factor), and T0.5 parameters in Table 96. Figures 113A-113C. Are graphs illustrating characterization of Mid Skid silk compositions by Dynamic Light Scattering. Mid skid silk/modified peptide compositions were diluted to a concentration of 1 mg/mL, filtered, and analyzed by the Zetasizer Pro (Malvern) to estimate the diameter particle size of each silk composition. Fig.113A. Intensity diameter particle size distribution by intensity measured for silk compositions AS101, AS102, AS103, AS104, and AS105. Fig.113B. Intensity diameter particle size distribution by intensity measured for silk compositions AS101, AS105, and Mid Skid silk (MS), to emphasize the size difference between AS101 and AS105. Fig.113C. Correlogram functions of silk compositions AS101, AS102, AS103, AS104, AS105, and Mid Skid silk (MS). Figure 114. is an illustration of the values for three molar mass moments (Mn, Mw, and Mz) as it relates to molar mass and the number of molecules at each molar mass. This example is applicable to a polydisperse sample; for a monodisperse sample, Mn = Mw = Mz. Figures 115A- 115B are analytical SEC-MALS of Low, Mid and High Molecular Weight Silk. Fig.115A. Weight Average Molecular Weight in kDa of Low, Mid, and High Molecular Weight Silk. Fig.115B. Polydispersity Index (PDI) measurements of Low, Mid, and High Molecular Weight Silk are shown. Figures 116A- 116B. Are analytical SEC-MALS of Low, Mid and High Molecular Weight Silk organized by Silk Type. Individual data points are show and the mean is represented by the heigh of the box. The bars encompass one standard deviation. Fig.116A. Weight-Average Molecular Weight Ranges for Low, Mid, and High Molecular Weight Silk. Fig.116B. PDI Ranges for Low, Mid, and High Molecular Weight Silk. Figures 117A- 117B are nalytical SEC-MALS of Low Skid silk/modified silk compositions and the constituent AS compositions as separated by Q-SEC (Q-eluent). Fig. 117A. Average molecular weight in kDa of Low Skid silk (LS) and AS77-AS81 are shown. Fig.117B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 103. Figures 118A- 118B are analytical SEC-MALS of Low Skid silk/modified silk compositions and the constituent AS compositions as separated by SEC. Fig.118A. Average molecular weight in kDa of Low Skid silk (LS) and AS82-AS89 are shown. Fig.118B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 104. Figures 119A- 119B are analytical SEC-MALS of Low Skid silk/modified silk compositions and the constituent AS compositions as separated by Q-HIC-SEC (Q-HIC- Eluent). Fig.119A. Average molecular weight in kDa of Low Skid silk (LS) and AS90-AS94 are shown. Fig. A119B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 105. Figures 120A- 120B are analytical SEC-MALS of Low Skid silk/modified silk compositions and the constituent AS compositions as separated by Q-HIC-SEC (Q-HIC- Flowthrough). Fig.120A. Average molecular weight in kDa of Low Skid silk (LS) and AS95-AS100 are shown. Fig.120B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 105. Figures 121A- 121B are analytical SEC-MALS of Mid Skid silk/modified silk compositions and the constituent AS compositions as separated by Q--SEC (Q-flow through). Fig.121A. Average molecular weight in kDa of Mid Skid silk (MS) and AS101-AS105 are shown. Fig.121B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 106. Figures 122A- 122B are analytical SEC-MALS of Mid Skid silk/modified silk compositions and the constituent AS compositions as separated by SEC. Fig.122A. Average molecular weight in kDa of Mid Skid silk (MS) and AS106-AS111 are shown. Fig.122B. Polydispersity (PDI) measurements are shown. The numerical data is presented in Table 107. Figures 123A- 123B are SEM images of unfinished leather. Figures 124A- 124B are SEM images of a silver tagged basecoat on leather. The leather was sprayed with 4 gr/sf of silver tagged basecoat. Figures 125A- 125B are SEM images of a silver tagged basecoat only on leather. The leather was sprayed with 4 gr/sf of silver tagged basecoat at higher magnification. Figure 126 is an SEM image of a silver tagged full L1 finish (basecoat + topcoat). The leather was sprayed with 4 gr/sf of silver tagged basecoat and 6gr/sf topcoat. This is a 45° turned sideview. Figures 127A- 127B are SEM images of a silver tagged full L1 finish (basecoat + topcoat). The leather was sprayed with 4 gr/sf of silver tagged basecoat and 6gr/sf topcoat. This is a cross-section view. Figure 128 is a photograph illustrating an example of failed milled leather (left) and passed milled leather (right). Figures 129A and 129B illustrate the process for forming a pattern on leather using paper release. Figure 130 illustrates the process for forming a pattern on leather for a large defect or snuff leather. Figures 131A - 131B are illustrations of the final composition of a leather article made with Paper Release Transfer Leather with the Activated Silk™ Topcoat layer (Fig. 131A) vs. a traditional topcoat (Fig.131B). The Activated Silk™ Topcoat layer is lower in solids concentration than a traditional topcoat (1.5 – 3% vs.15- 35%). When applied to Activated Silk™ L1 basecoat, it creates a composite. Figure 132 is an image of Low Grade Leather prior to Activated Silk™ L1 Paper release processing. Figure 133 is an image of Low Grade Leather after Activated Silk™ L1 Paper Release Processing. Figure 134 is an image of Low Grade Leather after Activated Silk™ L1 Paper Release Processing Close up. Figure 135 is a cross section view of unfinished crust. Figure 136 is a cross section view of crust with laminated film (pre-skin and skin). Figure 137 is a cross section view of crust with laminated film and basecoat. Figure 138 is a cross section view of crust with laminated film (pre-skin and skin) and basecoat. Figure 139 is a cross section view of crust with laminated film (pre-skin and skin) and basecoat. Figure 140 is a cross section view of crust with laminated film (pre-skin and skin) and basecoat. Figure 141 is a cross section view of finished leather of laminated film, basecoat and topcoat after rotopress processing. While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments. DETAILED DESCRIPTION In some embodiments, the disclosure provides a composition comprising a coating comprising two components. In some embodiments, the second component is impregnated onto the first component. In some embodiments, the second component goes through a phase change (e.g., and without limitation, Tg, polymerization, etc.). A first coating described herein may include without limitation a polymer or any protein disclosed herein, such as a biodegradable polyurethane, a silk protein, a collagen, casein, elastin, etc. A second coating described herein may include without limitation a cellulose derivative disclosed herein. A first coating and a second coating should not be limited in that order, as any coating disclosed herein may be interchanged with any other coating disclosed herein. While an ethyl cellulose may be usually brittle and can crack, in some embodiments, this disclosure provides for a flexible ethyl cellulose coating. Ten disclosure provides for coating any surface, without limitation, e.g., leather, fabric, wood, protective coating for food (fruit, vegetables, etc.). In some embodiments, a coating disclosed herein is made with two or more films (maybe starting from one film made of the two polymers) with a monolayer distribution for coating on substrates. As disclosed herein, a composite material and/or coating disclosed herein can be based, without limitation, on a \molecular entanglement whereby EC is free of crosslinker. In some embodiments, all the layers are fixed together with molecular interaction. In some embodiments, all molecular interactions are cured or set or polymerized. In some embodiments, a molecular interaction of the two layers whereby the film is cured and the molecules form larger polymeric structures. In some embodiments, an outer layer described herein comprises between 1% and 100% EC on the surface. In some embodiments, a first layer (in application against the surface to be coated): engages in molecular entanglement such as the first layer and the second layer became adhered; a first layer can adhere to uneven surface; a first layer is: thermoplastic, self-assembled, soluble in the solvent used for the second layer; first layer polymerize through crosslinking, self-assembly. In some embodiments, a first layer is resoluble and can be cured. In some embodiments, a polymer or protein, e.g., and without limitation, a silk protein, has a role in the first layer. In some embodiments, a second layer (deposited on top of the first layer and the outside layer): it is made by Ethyl Cellulose (EC) or a biomaterial or a polymer, in a dispersion of molecules; In some embodiments, this layer in solvent contains between about 1-5 gr/L by volume EC. In some embodiments, this layer can deliver dye, silk or other molecule to modify optical, haptics and mechanical properties. In some embodiments, EC is a protective barrier that can enhance the performance and characteristics of the first layer. In some embodiments, EC is mechanically resilient and enhance the water resistance properties. In some embodiments, EC can adhere to a dynamic first layer substrate. In some embodiments, EC can adhere to uneven first layer surface. In some embodiments, the majority of the EC faces outwardly to the external environment/forces. In some embodiments,, a protein or polymer, e.g., and without limitation, silk has a role in the second layer. Silk coated leather articles and methods of making thereof have been described in WO 2020/018821 and WO 2021/146654, each of which is incorporated herein by reference in its entirety. Leather is a material manufactured by treating the skin peeled off from an animal body with a series of physical mechanic and chemical methods, followed by tanning. The leather materials are composed of weaved collagen fiber bundles and trace amount of elastic fibers and reticular fibers, of which the collagen fiber is between 95 and 98 percent. The natural weaving structure of collagen fiber in natural leather is that the thicker fiber bundles sometimes are divided into several strands of thinner fiber bundles and the resulting thinner fiber bundles sometimes incorporate other fiber bundles to form another larger fiber bundle. Leather in its natural state is a nonwoven material where the fibrils of the fiber have grown together. The silk fibroin protein and collagen fibers in the leather are natural proteins composed of 22 proteinogenic amino acids. The silk protein has high affinity to the leather fibers (collagen fibers) resulted from the presence of hydrophilic amino acid residue in the silk fibroin protein (e.g., physical entanglement due to forming hydrogen bonding between silk protein fragments and leather fibers), for example, -OH group from serine, guanidine group from arginine, free amine group from lysine, -COOH group from aspartic acid and glutamic acid. Methods of coating leather including for examples a method including: • Leather crusts may first be treated with stucco and/or ground to prepare surface for basecoat application. Stucco is typically used with leather that has scars and deep defects and can be applied by rollers. Ground is typically used for buffed and/or split leather and can be applied via rollercoater or spray. • Separately, an appropriate grain release paper that bears the negative engraving of the print design is applied with the basecoat solution and dried. The two substrates, treated leather and coated release paper, are then stacked together with the coated sides facing each other. The stacked substrate is then laminated through high pressure and temperature. Once laminated, the release paper is removed, leaving the print design on the semi-finished leather. • To finish the leather, the topcoat is applied via spray or rollercoater and is dried and ironed. In some embodiments, herein described silk fibroin-based protein fragments and solutions may find application as color performance enhancer for leather or leather articles. In some embodiments, this disclosure provides silk treated leather or leather articles exhibiting good dyeability, excellent color fastness and enhanced color saturation. The treatment on the leather and leather articles with silk fibroin-based protein fragments and solutions enhances the quality and aesthetic properties of the natural leather using non-toxic, sustainable and natural silk based composition. The silk treatment process disclosed herein advances leather products while respecting its heritage and craft without disruption to the leather tanning and creating process. SPF Definitions and Properties As used herein, “silk protein fragments” (SPF) include, without limitation, one or more of: “silk fibroin fragments” as defined herein; “recombinant silk fragments” as defined herein; “spider silk fragments” as defined herein; “silk fibroin-like protein fragments” as defined herein; “chemically modified silk fragments” as defined herein; and/or “sericin or sericin fragments” as defined herein. SPF may have any molecular weight values or ranges described herein, and any polydispersity values or ranges described herein. As used herein, in some embodiments the term “silk protein fragment” also refers to a silk protein that comprises or consists of at least two identical repetitive units which each independently selected from naturally-occurring silk polypeptides or of variations thereof, amino acid sequences of naturally-occurring silk polypeptides, or of combinations of both. SPF Molecular Weight and Polydispersity In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 1 to about 5 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 5 to about 10 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 10 to about 15 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 15 to about 20 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 14 to about 30 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 20 to about 25 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 25 to about 30 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 30 to about 35 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 35 to about 40 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 39 to about 54 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 40 to about 45 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 45 to about 50 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 50 to about 55 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 55 to about 60 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 60 to about 65 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 65 to about 70 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 70 to about 75 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 75 to about 80 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 80 to about 85 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 85 to about 90 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 90 to about 95 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 95 to about 100 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 100 to about 105 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 105 to about 110 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 110 to about 115 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 115 to about 120 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 120 to about 125 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 125 to about 130 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 130 to about 135 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 135 to about 140 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 140 to about 145 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 145 to about 150 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 150 to about 155 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 155 to about 160 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 160 to about 165 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 165 to about 170 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 170 to about 175 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 175 to about 180 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 180 to about 185 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 185 to about 190 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 190 to about 195 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 195 to about 200 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 200 to about 205 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 205 to about 210 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 210 to about 215 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 215 to about 220 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 220 to about 225 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 225 to about 230 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 230 to about 235 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 235 to about 240 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 240 to about 245 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 245 to about 250 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 250 to about 255 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 255 to about 260 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 260 to about 265 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 265 to about 270 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 270 to about 275 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 275 to about 280 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 280 to about 285 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 285 to about 290 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 290 to about 295 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 295 to about 300 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 300 to about 305 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 305 to about 310 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 310 to about 315 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 315 to about 320 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 320 to about 325 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 325 to about 330 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 330 to about 335 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 335 to about 340 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 340 to about 345 kDa. In an embodiment, a composition of the present disclosure includes SPF having an average weight average molecular weight selected from between about 345 to about 350 kDa. In some embodiments, compositions of the present disclosure include SPF compositions selected from compositions #1001 to #2450, having weight average molecular weights selected from about 1 kDa to about 145 kDa, and a polydispersity selected from between 1 and about 5 (including, without limitation, a polydispersity of 1), between 1 and about 1.5 (including, without limitation, a polydispersity of 1), between about 1.5 and about 2, between about 1.5 and about 3, between about 2 and about 2.5, between about 2.5 and about 3, between about 3 and about 3.5, between about 3.5 and about 4, between about 4 and about 4.5, and between about 4.5 and about 5: P (abou MW (about) 1 kD

2 kD 3 kD 4 kD 5 kD 6 kD 7 kD 8 kD 9 kD 10 kD 11 kD 12 kD 13 kD 14 kD 15 kD 16 kD 17 kD 18 kD 19 kD 20 kD 21 kD 22 kD 23 kD 24 kD 25 kD 26 kD 27 kD 28 kD 29 kD 30 kD 31 kD 32 kD 33 kD 34 kD 35 kD 36 kD 37 kD 38 kD 39 kD 40 kD 41 kD 42 kD 43 kD 44 kD 45 kD 46 kD 47 kD

48 kD 49 kD 50 kD 51 kD 52 kD 53 kD 54 kD 55 kD 56 kD 57 kD 58 kD 59 kD 60 kD 61 kD 62 kD 63 kD 64 kD 65 kD 66 kD 67 kD 68 kD 69 kD 70 kD 71 kD 72 kD 73 kD 74 kD 75 kD 76 kD 77 kD 78 kD 79 kD 80 kD 81 kD 82 kD 83 kD 84 kD 85 kD 86 kD 87 kD 88 kD 89 kD 90 kD 91 kD 92 kD 93 kD

94 kD 95 kD 96 kD 97 kD 98 kD 99 kD 100 kD 101 kD 102 kD 103 kD 104 kD 105 kD 106 kD 107 kD 108 kD 109 kD 110 kD 111 kD 112 kD 113 kD 114 kD 115 kD 116 kD 117 kD 118 kD 119 kD 120 kD 121 kD 122 kD 123 kD 124 kD 125 kD 126 kD 127 kD 128 kD 129 kD 130 kD 131 kD 132 kD 133 kD 134 kD 135 kD 136 kD 137 kD 138 kD 139 kD

In some embodiments, the molecular weights described herein may be converted to the approximate number of amino acids contained within the respective SPF, as would be understood by a person having ordinary skill in the art. For example, the average weight of an amino acid may be about 110 daltons (i.e., 110 g/mol). Therefore, in some embodiments, dividing the molecular weight of a linear protein by 110 daltons may be used to approximate the number of amino acid residues contained therein. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between 1 to about 5.0, including, without limitation, a polydispersity of 1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 1.5 to about 3.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between 1 to about 1.5, including, without limitation, a polydispersity of 1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 1.5 to about 2.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 2.0 to about 2.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 2.5 to about 3.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 3.0 to about 3.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 3.5 to about 4.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 4.0 to about 4.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity selected from between about 4.5 to about 5.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of 1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.2. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.3. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.4. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.6. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.7. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.8. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 1.9. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.2. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.3. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.4. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.6. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.7. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.8. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 2.9. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.2. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.3. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.4. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.6. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.7. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.8. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 3.9. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.0. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.1. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.2. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.3. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.4. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.5. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.6. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.7. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.8. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 4.9. In an embodiment, SPF in a composition of the present disclosure have a polydispersity of about 5.0. In some embodiments, in compositions described herein having combinations of low, medium, and/or high molecular weight SPF, such low, medium, and/or high molecular weight SPF may have the same or different polydispersities. Silk Fibroin Fragments Methods of making silk fibroin or silk fibroin protein fragments and their applications in various fields are known and are described for example in U.S. Patents Nos.9,187,538, 9,511,012, 9,517,191, 9,522,107, 9,522,108, 9,545,369, and 10,166,177, 10,287,728 and 10,301,768, all of which are incorporated herein in their entireties. Raw silk from silkworm Bombyx mori is composed of two primary proteins: silk fibroin (approximately 75%) and sericin (approximately 25%). Silk fibroin is a fibrous protein with a semi-crystalline structure that provides stiffness and strength. As used herein, the term “silk fibroin” means the fibers of the cocoon of Bombyx mori having a weight average molecular weight of about 370,000 Da. The crude silkworm fiber consists of a double thread of fibroin. The adhesive substance holding these double fibers together is sericin. The silk fibroin is composed of a heavy chain having a weight average molecular weight of about 350,000 Da (H chain), and a light chain having a weight average molecular weight about 25,000 Da (L chain). Silk fibroin is an amphiphilic polymer with large hydrophobic domains occupying the major component of the polymer, which has a high molecular weight. The hydrophobic regions are interrupted by small hydrophilic spacers, and the N- and C-termini of the chains are also highly hydrophilic. The hydrophobic domains of the H-chain contain a repetitive hexapeptide sequence of Gly- Ala-Gly-Ala-Gly-Ser and repeats of Gly-Ala/Ser/Tyr dipeptides, which can form stable anti- parallel-sheet crystallites. The amino acid sequence of the L-chain is non-repetitive, so the L- chain is more hydrophilic and relatively elastic. The hydrophilic (Tyr, Ser) and hydrophobic (Gly, Ala) chain segments in silk fibroin molecules are arranged alternatively such that allows self-assembling of silk fibroin molecules. Provided herein are methods for producing pure and highly scalable silk fibroin- protein fragment mixture solutions that may be used across multiple industries for a variety of applications. Without wishing to be bound by any particular theory, it is believed that these methods are equally applicable to fragmentation of any SPF described herein, including without limitation recombinant silk proteins, and fragmentation of silk-like or fibroin-like proteins. As used herein, the term “fibroin” includes silk worm fibroin and insect or spider silk protein. In an embodiment, fibroin is obtained from Bombyx mori. Raw silk from Bombyx mori is composed of two primary proteins: silk fibroin (approximately 75%) and sericin (approximately 25%). Silk fibroin is a fibrous protein with a semi-crystalline structure that provides stiffness and strength. As used herein, the term “silk fibroin” means the fibers of the cocoon of Bombyx mori having a weight average molecular weight of about 370,000 Da. Conversion of these insoluble silk fibroin fibrils into water-soluble silk fibroin protein fragments requires the addition of a concentrated neutral salt (e.g., 8-10 M lithium bromide), which interferes with inter- and intramolecular ionic and hydrogen bonding that would otherwise render the fibroin protein insoluble in water. Methods of making silk fibroin protein fragments, and/or compositions thereof, are known and are described for example in U.S. Patents Nos.9,187,538, 9,511,012, 9,517,191, 9,522,107, 9,522,108, 9,545,369, and 10,166,177. The raw silk cocoons from the silkworm Bombyx mori was cut into pieces. The pieces silk cocoons were processed in an aqueous solution of Na₂CO₃ at about 100 °C for about 60 minutes to remove sericin (degumming). The volume of the water used equals about 0.4 x raw silk weight and the amount of Na₂CO₃ is about 0.848 x the weight of the raw silk cocoon pieces. The resulting degummed silk cocoon pieces were rinsed with deionized water three times at about 60 °C (20 minutes per rinse). The volume of rinse water for each cycle was 0.2 L x the weight of the raw silk cocoon pieces. The excess water from the degummed silk cocoon pieces was removed. After the DI water washing step, the wet degummed silk cocoon pieces were dried at room temperature. The degummed silk cocoon pieces were mixed with a LiBr solution, and the mixture was heated to about 100 °C. The warmed mixture was placed in a dry oven and was heated at about 100 °C for about 60 minutes to achieve complete dissolution of the native silk protein. The resulting silk fibroin solution was filtered and dialyzed using Tangential Flow Filtration (TFF) and a 10 kDa membrane against deionized water for 72 hours. The resulting silk fibroin aqueous solution has a concentration of about 8.5 wt. %. Then, 8.5 % silk solution was diluted with water to result in a 1.0 % w/v silk solution. TFF can then be used to further concentrate the pure silk solution to a concentration of 20.0 % w/w silk to water. Dialyzing the silk through a series of water changes is a manual and time intensive process, which could be accelerated by changing certain parameters, for example diluting the silk solution prior to dialysis. The dialysis process could be scaled for manufacturing by using semi-automated equipment, for example a tangential flow filtration system. In some embodiments, the silk solutions are prepared under various preparation condition parameters such as: 90 °C 30 min, 90 °C 60 min, 100 °C 30 min, and 100 °C 60 min. Briefly, 9.3 M LiBr was prepared and allowed to sit at room temperature for at least 30 minutes.5 mL of LiBr solution was added to 1.25 g of silk and placed in the 60 °C oven. Samples from each set were removed at 4, 6, 8, 12, 24, 168 and 192 hours. In some embodiments, the silk solutions are prepared under various preparation condition parameters such as: 90 °C 30 min, 90 °C 60 min, 100 °C 30 min, and 100 °C 60 min. Briefly, 9.3 M LiBr solution was heated to one of four temperatures: 60 °C, 80 °C, 100 °C or boiling.5 mL of hot LiBr solution was added to 1.25 g of silk and placed in the 60 °C oven. Samples from each set were removed at 1, 4 and 6 hours. In some embodiments, the silk solutions are prepared under various preparation condition parameters such as: Four different silk extraction combinations were used: 90 °C 30 min, 90 °C 60 min, 100 °C 30 min, and 100 °C 60 min. Briefly, 9.3 M LiBr solution was heated to one of four temperatures: 60 °C, 80 °C, 100 °C or boiling.5 mL of hot LiBr solution was added to 1.25 g of silk and placed in the oven at the same temperature of the LiBr. Samples from each set were removed at 1, 4 and 6 hours.1 mL of each sample was added to 7.5 mL of 9.3 M LiBr and refrigerated for viscosity testing. In some embodiments, SPF are obtained by dissolving raw unscoured, partially scoured, or scoured silkworm fibers with a neutral lithium bromide salt. The raw silkworm silks are processed under selected temperature and other conditions in order to remove any sericin and achieve the desired weight average molecular weight (M_W) and polydispersity (PD) of the fragment mixture. Selection of process parameters may be altered to achieve distinct final silk protein fragment characteristics depending upon the intended use. The resulting final fragment solution is silk fibroin protein fragments and water with parts per million (ppm) to non-detectable levels of process contaminants, levels acceptable in the pharmaceutical, medical and consumer eye care markets. The concentration, size and polydispersity of SPF may further be altered depending upon the desired use and performance requirements. FIG.1 is a flow chart showing various embodiments for producing pure silk fibroin protein fragments (SPFs) of the present disclosure. It should be understood that not all of the steps illustrated are necessarily required to fabricate all silk solutions of the present disclosure. As illustrated in FIG.1, step A, cocoons (heat-treated or non-heat-treated), silk fibers, silk powder, spider silk or recombinant spider silk can be used as the silk source. If starting from raw silk cocoons from Bombyx mori, the cocoons can be cut into small pieces, for example pieces of approximately equal size, step B1. The raw silk is then extracted and rinsed to remove any sericin, step C1a. This results in substantially sericin free raw silk. In an embodiment, water is heated to a temperature between 84 °C and 100 °C (ideally boiling) and then Na₂CO₃ (sodium carbonate) is added to the boiling water until the Na₂CO₃ is completely dissolved. The raw silk is added to the boiling water/ Na₂CO₃ (100 °C) and submerged for approximately 15 - 90 minutes, where boiling for a longer time results in smaller silk protein fragments. In an embodiment, the water volume equals about 0.4 x raw silk weight and the Na₂CO₃ volume equals about 0.848 x raw silk weight. In an embodiment, the water volume equals 0.1 x raw silk weight and the Na₂CO₃ volume is maintained at 2.12 g/L. Subsequently, the water dissolved Na₂CO₃ solution is drained and excess water/ Na₂CO₃ is removed from the silk fibroin fibers (e.g., ring out the fibroin extract by hand, spin cycle using a machine, etc.). The resulting silk fibroin extract is rinsed with warm to hot water to remove any remaining adsorbed sericin or contaminate, typically at a temperature range of about 40 °C to about 80 °C, changing the volume of water at least once (repeated for as many times as required). The resulting silk fibroin extract is a substantially sericin-depleted silk fibroin. In an embodiment, the resulting silk fibroin extract is rinsed with water at a temperature of about 60 °C. In an embodiment, the volume of rinse water for each cycle equals 0.1 L to 0.2 L x raw silk weight. It may be advantageous to agitate, turn or circulate the rinse water to maximize the rinse effect. After rinsing, excess water is removed from the extracted silk fibroin fibers (e.g., ring out fibroin extract by hand or using a machine). Alternatively, methods known to one skilled in the art such as pressure, temperature, or other reagents or combinations thereof may be used for the purpose of sericin extraction. Alternatively, the silk gland (100% sericin free silk protein) can be removed directly from a worm. This would result in liquid silk protein, without any alteration of the protein structure, free of sericin. The extracted fibroin fibers are then allowed to dry completely. Once dry, the extracted silk fibroin is dissolved using a solvent added to the silk fibroin at a temperature between ambient and boiling, step C1b. In an embodiment, the solvent is a solution of Lithium bromide (LiBr) (boiling for LiBr is 140 °C). Alternatively, the extracted fibroin fibers are not dried but wet and placed in the solvent; solvent concentration can then be varied to achieve similar concentrations as to when adding dried silk to the solvent. The final concentration of LiBr solvent can range from 0.1 M to 9.3 M. Complete dissolution of the extracted fibroin fibers can be achieved by varying the treatment time and temperature along with the concentration of dissolving solvent. Other solvents may be used including, but not limited to, phosphate phosphoric acid, calcium nitrate, calcium chloride solution or other concentrated aqueous solutions of inorganic salts. To ensure complete dissolution, the silk fibers should be fully immersed within the already heated solvent solution and then maintained at a temperature ranging from about 60 °C to about 140 °C for 1-168 hrs. In an embodiment, the silk fibers should be fully immersed within the solvent solution and then placed into a dry oven at a temperature of about 100 °C for about 1 hour. The temperature at which the silk fibroin extract is added to the LiBr solution (or vice versa) has an effect on the time required to completely dissolve the fibroin and on the resulting molecular weight and polydispersity of the final SPF mixture solution. In an embodiment, silk solvent solution concentration is less than or equal to 20% w/v. In addition, agitation during introduction or dissolution may be used to facilitate dissolution at varying temperatures and concentrations. The temperature of the LiBr solution will provide control over the silk protein fragment mixture molecular weight and polydispersity created. In an embodiment, a higher temperature will more quickly dissolve the silk offering enhanced process scalability and mass production of silk solution. In an embodiment, using a LiBr solution heated to a temperature from 80 °C to 140 °C reduces the time required in an oven in order to achieve full dissolution. Varying time and temperature at or above 60 °C of the dissolution solvent will alter and control the MW and polydispersity of the SPF mixture solutions formed from the original molecular weight of the native silk fibroin protein. Alternatively, whole cocoons may be placed directly into a solvent, such as LiBr, bypassing extraction, step B2. This requires subsequent filtration of silk worm particles from the silk and solvent solution and sericin removal using methods know in the art for separating hydrophobic and hydrophilic proteins such as a column separation and/or chromatography, ion exchange, chemical precipitation with salt and/or pH, and or enzymatic digestion and filtration or extraction, all methods are common examples and without limitation for standard protein separation methods, step C2. Non-heat treated cocoons with the silkworm removed, may alternatively be placed into a solvent such as LiBr, bypassing extraction. The methods described above may be used for sericin separation, with the advantage that non-heat treated cocoons will contain significantly less worm debris. Dialysis may be used to remove the dissolution solvent from the resulting dissolved fibroin protein fragment solution by dialyzing the solution against a volume of water, step E1. Pre-filtration prior to dialysis is helpful to remove any debris (i.e., silk worm remnants) from the silk and LiBr solution, step D. In one example, a 3 µm or 5 µm filter is used with a flow- rate of 200-300 mL/min to filter a 0.1% to 1.0% silk-LiBr solution prior to dialysis and potential concentration if desired. A method disclosed herein, as described above, is to use time and/or temperature to decrease the concentration from 9.3 M LiBr to a range from 0.1 M to 9.3 M to facilitate filtration and downstream dialysis, particularly when considering creating a scalable process method. Alternatively, without the use of additional time or temperate, a 9.3 M LiBr-silk protein fragment solution may be diluted with water to facilitate debris filtration and dialysis. The result of dissolution at the desired time and temperate filtration is a translucent particle-free room temperature shelf-stable silk protein fragment- LiBr solution of a known MW and polydispersity. It is advantageous to change the dialysis water regularly until the solvent has been removed (e.g., change water after 1 hour, 4 hours, and then every 12 hours for a total of 6 water changes). The total number of water volume changes may be varied based on the resulting concentration of solvent used for silk protein dissolution and fragmentation. After dialysis, the final silk solution maybe further filtered to remove any remaining debris (i.e., silk worm remnants). Alternatively, Tangential Flow Filtration (TFF), which is a rapid and efficient method for the separation and purification of biomolecules, may be used to remove the solvent from the resulting dissolved fibroin solution, step E2. TFF offers a highly pure aqueous silk protein fragment solution and enables scalability of the process in order to produce large volumes of the solution in a controlled and repeatable manner. The silk and LiBr solution may be diluted prior to TFF (20 % down to 0.1 % silk in either water or LiBr). Pre-filtration as described above prior to TFF processing may maintain filter efficiency and potentially avoids the creation of silk gel boundary layers on the filter’s surface as the result of the presence of debris particles. Pre-filtration prior to TFF is also helpful to remove any remaining debris (i.e., silk worm remnants) from the silk and LiBr solution that may cause spontaneous or long-term gelation of the resulting water only solution, step D. TFF, recirculating or single pass, may be used for the creation of water-silk protein fragment solutions ranging from 0.1 % silk to 30.0 % silk (more preferably, 0.1 % - 6.0 % silk). Different cutoff size TFF membranes may be required based upon the desired concentration, molecular weight and polydispersity of the silk protein fragment mixture in solution. Membranes ranging from 1- 100 kDa may be necessary for varying molecular weight silk solutions created for example by varying the length of extraction boil time or the time and temperate in dissolution solvent (e.g., LiBr). In an embodiment, a TFF 5 or 10 kDa membrane is used to purify the silk protein fragment mixture solution and to create the final desired silk-to-water ratio. As well, TFF single pass, TFF, and other methods known in the art, such as a falling film evaporator, may be used to concentrate the solution following removal of the dissolution solvent (e.g., LiBr) (with resulting desired concentration ranging from 0.1% to 30 % silk). This can be used as an alternative to standard HFIP concentration methods known in the art to create a water- based solution. A larger pore membrane could also be utilized to filter out small silk protein fragments and to create a solution of higher molecular weight silk with and/or without tighter polydispersity values. An assay for LiBr and Na₂CO₃ detection can be performed using an HPLC system equipped with evaporative light scattering detector (ELSD). The calculation was performed by linear regression of the resulting peak areas for the analyte plotted against concentration. More than one sample of a number of formulations of the present disclosure was used for sample preparation and analysis. Generally, four samples of different formulations were weighed directly in a 10 mL volumetric flask. The samples were suspended in 5 mL of 20 mM ammonium formate (pH 3.0) and kept at 2-8 °C for 2 hours with occasional shaking to extract analytes from the film. After 2 hours the solution was diluted with 20 mM ammonium formate (pH 3.0). The sample solution from the volumetric flask was transferred into HPLC vials and injected into the HPLC-ELSD system for the estimation of sodium carbonate and lithium bromide. The analytical method developed for the quantitation of Na2CO3 and LiBr in silk protein formulations was found to be linear in the range 10 - 165 µg/mL, with RSD for injection precision as 2% and 1% for area and 0.38% and 0.19% for retention time for sodium carbonate and lithium bromide respectively. The analytical method can be applied for the quantitative determination of sodium carbonate and lithium bromide in silk protein formulations. FIG.2 is a flow chart showing various parameters that can be modified during the process of producing a silk protein fragment solution of the present disclosure during the extraction and the dissolution steps. Select method parameters may be altered to achieve distinct final solution characteristics depending upon the intended use, e.g., molecular weight and polydispersity. It should be understood that not all of the steps illustrated are necessarily required to fabricate all silk solutions of the present disclosure. In an embodiment, silk protein fragment solutions useful for a wide variety of applications are prepared according to the following steps: forming pieces of silk cocoons from the Bombyx mori silkworm; extracting the pieces at about 100 °C in a Na2CO3 water solution for about 60 minutes, wherein a volume of the water equals about 0.4 × raw silk weight and the amount of Na2CO3 is about 0.848 × the weight of the pieces to form a silk fibroin extract; triple rinsing the silk fibroin extract at about 60 °C for about 20 minutes per rinse in a volume of rinse water, wherein the rinse water for each cycle equals about 0.2 L × the weight of the pieces; removing excess water from the silk fibroin extract; drying the silk fibroin extract; dissolving the dry silk fibroin extract in a LiBr solution, wherein the LiBr solution is first heated to about 100 °C to create a silk and LiBr solution and maintained; placing the silk and LiBr solution in a dry oven at about 100 °C for about 60 minutes to achieve complete dissolution and further fragmentation of the native silk protein structure into mixture with desired molecular weight and polydispersity; filtering the solution to remove any remaining debris from the silkworm; diluting the solution with water to result in a 1.0 wt. % silk solution; and removing solvent from the solution using Tangential Flow Filtration (TFF). In an embodiment, a 10 kDa membrane is utilized to purify the silk solution and create the final desired silk-to-water ratio. TFF can then be used to further concentrate the silk solution to a concentration of 2.0 wt. % silk in water. Without wishing to be bound by any particular theory, varying extraction (i.e., time and temperature), LiBr (i.e., temperature of LiBr solution when added to silk fibroin extract or vice versa) and dissolution (i.e., time and temperature) parameters results in solvent and silk solutions with different viscosities, homogeneities, and colors. Also without wishing to be bound by any particular theory, increasing the temperature for extraction, lengthening the extraction time, using a higher temperature LiBr solution at emersion and over time when dissolving the silk and increasing the time at temperature (e.g., in an oven as shown here, or an alternative heat source) all resulted in less viscous and more homogeneous solvent and silk solutions. The extraction step could be completed in a larger vessel, for example an industrial washing machine where temperatures at or in between 60 °C to 100 °C can be maintained. The rinsing step could also be completed in the industrial washing machine, eliminating the manual rinse cycles. Dissolution of the silk in LiBr solution could occur in a vessel other than a convection oven, for example a stirred tank reactor. Dialyzing the silk through a series of water changes is a manual and time intensive process, which could be accelerated by changing certain parameters, for example diluting the silk solution prior to dialysis. The dialysis process could be scaled for manufacturing by using semi-automated equipment, for example a tangential flow filtration system. Varying extraction (i.e., time and temperature), LiBr (i.e., temperature of LiBr solution when added to silk fibroin extract or vice versa) and dissolution (i.e., time and temperature) parameters results in solvent and silk solutions with different viscosities, homogeneities, and colors. Increasing the temperature for extraction, lengthening the extraction time, using a higher temperature LiBr solution at emersion and over time when dissolving the silk and increasing the time at temperature (e.g., in an oven as shown here, or an alternative heat source) all resulted in less viscous and more homogeneous solvent and silk solutions. While almost all parameters resulted in a viable silk solution, methods that allow complete dissolution to be achieved in fewer than 4 to 6 hours are preferred for process scalability. In an embodiment, solutions of silk fibroin protein fragments having a weight average selected from between about 6 kDa to about 17 kDa are prepared according to following steps: degumming a silk source by adding the silk source to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of between about 30 minutes to about 60 minutes; removing sericin from the solution to produce a silk fibroin extract comprising non- detectable levels of sericin; draining the solution from the silk fibroin extract; dissolving the silk fibroin extract in a solution of lithium bromide having a starting temperature upon placement of the silk fibroin extract in the lithium bromide solution that ranges from about 60 °C to about 140 °C; maintaining the solution of silk fibroin-lithium bromide in an oven having a temperature of about 140 °C for a period of at most 1 hour; removing the lithium bromide from the silk fibroin extract; and producing an aqueous solution of silk protein fragments, the aqueous solution comprising: fragments having a weight average molecular weight selected from between about 6 kDa to about 17 kDa, and a polydispersity of between 1 and about 5, or between about 1.5 and about 3.0. The method may further comprise drying the silk fibroin extract prior to the dissolving step. The aqueous solution of silk fibroin protein fragments may comprise lithium bromide residuals of less than 300 ppm as measured using a high-performance liquid chromatography lithium bromide assay. The aqueous solution of silk fibroin protein fragments may comprise sodium carbonate residuals of less than 100 ppm as measured using a high-performance liquid chromatography sodium carbonate assay. The aqueous solution of silk fibroin protein fragments may be lyophilized. In some embodiments, the silk fibroin protein fragment solution may be further processed into various forms including gel, powder, and nanofiber. In an embodiment, solutions of silk fibroin protein fragments having a weight average molecular weight selected from between about 17 kDa to about 39 kDa are prepared according to the following steps: adding a silk source to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of between about 30 minutes to about 60 minutes so as to result in degumming; removing sericin from the solution to produce a silk fibroin extract comprising non-detectable levels of sericin; draining the solution from the silk fibroin extract; dissolving the silk fibroin extract in a solution of lithium bromide having a starting temperature upon placement of the silk fibroin extract in the lithium bromide solution that ranges from about 80 °C to about 140 °C; maintaining the solution of silk fibroin-lithium bromide in a dry oven having a temperature in the range between about 60 °C to about 100 °C for a period of at most 1 hour; removing the lithium bromide from the silk fibroin extract; and producing an aqueous solution of silk fibroin protein fragments, wherein the aqueous solution of silk fibroin protein fragments comprises lithium bromide residuals of between about 10 ppm and about 300 ppm, wherein the aqueous solution of silk protein fragments comprises sodium carbonate residuals of between about 10 ppm and about 100 ppm, wherein the aqueous solution of silk fibroin protein fragments comprises fragments having a weight average molecular weight selected from between about 17 kDa to about 39 kDa, and a polydispersity of between 1 and about 5, or between about 1.5 and about 3.0. The method may further comprise drying the silk fibroin extract prior to the dissolving step. The aqueous solution of silk fibroin protein fragments may comprise lithium bromide residuals of less than 300 ppm as measured using a high- performance liquid chromatography lithium bromide assay. The aqueous solution of silk fibroin protein fragments may comprise sodium carbonate residuals of less than 100 ppm as measured using a high-performance liquid chromatography sodium carbonate assay. In some embodiments, a method for preparing an aqueous solution of silk fibroin protein fragments having an average weight average molecular weight selected from between about 6 kDa to about 17 kDa includes the steps of: degumming a silk source by adding the silk source to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of between about 30 minutes to about 60 minutes; removing sericin from the solution to produce a silk fibroin extract comprising non-detectable levels of sericin; draining the solution from the silk fibroin extract; dissolving the silk fibroin extract in a solution of lithium bromide having a starting temperature upon placement of the silk fibroin extract in the lithium bromide solution that ranges from about 60 °C to about 140 °C; maintaining the solution of silk fibroin-lithium bromide in an oven having a temperature of about 140 °C for a period of at least 1 hour; removing the lithium bromide from the silk fibroin extract; and producing an aqueous solution of silk protein fragments, the aqueous solution comprising: fragments having an average weight average molecular weight selected from between about 6 kDa to about 17 kDa, and a polydispersity of between 1 and about 5, or between about 1.5 and about 3.0. The method may further comprise drying the silk fibroin extract prior to the dissolving step. The aqueous solution of pure silk fibroin protein fragments may comprise lithium bromide residuals of less than 300 ppm as measured using a high-performance liquid chromatography lithium bromide assay . The aqueous solution of pure silk fibroin protein fragments may comprise sodium carbonate residuals of less than 100 ppm as measured using a high-performance liquid chromatography sodium carbonate assay. The method may further comprise adding a therapeutic agent to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding a molecule selected from one of an antioxidant or an enzyme to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding a vitamin to the aqueous solution of pure silk fibroin protein fragments. The vitamin may be vitamin C or a derivative thereof. The aqueous solution of pure silk fibroin protein fragments may be lyophilized. The method may further comprise adding an alpha hydroxy acid to the aqueous solution of pure silk fibroin protein fragments. The alpha hydroxy acid may be selected from the group consisting of glycolic acid, lactic acid, tartaric acid and citric acid. The method may further comprise adding hyaluronic acid or its salt form at a concentration of about 0.5 % to about 10.0 % to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding at least one of zinc oxide or titanium dioxide. A film may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The film may comprise from about 1.0 wt. % to about 50,0 wt. % of vitamin C or a derivative thereof. The film may have a water content ranging from about 2.0 wt. % to about 20.0 wt. %. The film may comprise from about 30.0 wt. % to about 99.5 wt. % of pure silk fibroin protein fragments. A gel may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The gel may comprise from about 0.5 wt. % to about 20.0 wt. % of vitamin C or a derivative thereof. The gel may have a silk content of at least 2 % and a vitamin content of at least 20 %. In some embodiments, a method for preparing an aqueous solution of silk fibroin protein fragments having an average weight average molecular weight selected from between about 17 kDa to about 39 kDa includes the steps of: adding a silk source to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of between about 30 minutes to about 60 minutes so as to result in degumming; removing sericin from the solution to produce a silk fibroin extract comprising non-detectable levels of sericin; draining the solution from the silk fibroin extract; dissolving the silk fibroin extract in a solution of lithium bromide having a starting temperature upon placement of the silk fibroin extract in the lithium bromide solution that ranges from about 80 °C to about 140 °C; maintaining the solution of silk fibroin-lithium bromide in a dry oven having a temperature in the range between about 60 °C to about 100 °C for a period of at least 1 hour; removing the lithium bromide from the silk fibroin extract; and producing an aqueous solution of pure silk fibroin protein fragments, wherein the aqueous solution of pure silk fibroin protein fragments comprises lithium bromide residuals of between about 10 ppm and about 300 ppm, wherein the aqueous solution of silk protein fragments comprises sodium carbonate residuals of between about 10 ppm and about 100 ppm, wherein the aqueous solution of pure silk fibroin protein fragments comprises fragments having an average weight average molecular weight selected from between about 17 kDa to about 39 kDa, and a polydispersity of between 1 and about 5, or between about 1.5 and about 3.0. The method may further comprise drying the silk fibroin extract prior to the dissolving step. The aqueous solution of pure silk fibroin protein fragments may comprise lithium bromide residuals of less than 300 ppm as measured using a high-performance liquid chromatography lithium bromide assay. The aqueous solution of pure silk fibroin protein fragments may comprise sodium carbonate residuals of less than 100 ppm as measured using a high-performance liquid chromatography sodium carbonate assay. The method may further comprise adding a therapeutic agent to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding a molecule selected from one of an antioxidant or an enzyme to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding a vitamin to the aqueous solution of pure silk fibroin protein fragments. The vitamin may be vitamin C or a derivative thereof. The aqueous solution of pure silk fibroin protein fragments may be lyophilized. The method may further comprise adding an alpha hydroxy acid to the aqueous solution of pure silk fibroin protein fragments. The alpha hydroxy acid may be selected from the group consisting of glycolic acid, lactic acid, tartaric acid and citric acid. The method may further comprise adding hyaluronic acid or its salt form at a concentration of about 0.5% to about 10.0% to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding at least one of zinc oxide or titanium dioxide. A film may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The film may comprise from about 1 ,0 wt. % to about 50.0 wt. % of vitamin C or a derivative thereof. The film may have a water content ranging from about 2.0 wt. % to about 20.0 wt. %. The film may comprise from about 30.0 wt. % to about 99.5 wt. % of pure silk fibroin protein fragments. A gel may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The gel may comprise from about 0.5 wt. % to about 20.0 wt. % of vitamin C or a derivative thereof. The gel may have a silk content of at least 2% and a vitamin content of at least 20%. In an embodiment, solutions of silk fibroin protein fragments having a weight average molecular weight selected from between about 39 kDa to about 80 kDa are prepared according to the following steps: adding a silk source to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of about 30 minutes so as to result in degumming; removing sericin from the solution to produce a silk fibroin extract comprising non-detectable levels of sericin; draining the solution from the silk fibroin extract; dissolving the silk fibroin extract in a solution of lithium bromide having a starting temperature upon placement of the silk fibroin extract in the lithium bromide solution that ranges from about 80 °C to about 140 °C; maintaining the solution of silk fibroin-lithium bromide in a dry oven having a temperature in the range between about 60 °C to about 100 °C for a period of at most 1 hour; removing the lithium bromide from the silk fibroin extract; and producing an aqueous solution of silk fibroin protein fragments, wherein the aqueous solution of silk fibroin protein fragments comprises lithium bromide residuals of between about 10 ppm and about 300 ppm, sodium carbonate residuals of between about 10 ppm and about 100 ppm, fragments having a weight average molecular weight selected from between about 39 kDa to about 80 kDa, and a polydispersity of between 1 and about 5, or between about 1.5 and about 3.0. The method may further comprise drying the silk fibroin extract prior to the dissolving step. The aqueous solution of silk fibroin protein fragments may comprise lithium bromide residuals of less than 300 ppm as measured using a high-performance liquid chromatography lithium bromide assay. The aqueous solution of silk fibroin protein fragments may comprise sodium carbonate residuals of less than 100 ppm as measured using a high-performance liquid chromatography sodium carbonate assay. In some embodiments, the method may further comprise adding an active agent (e.g., therapeutic agent) to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding an active agent selected from one of an antioxidant or an enzyme to the aqueous solution of pure silk fibroin protein fragments. The method may further comprise adding a vitamin to the aqueous solution of pure silk fibroin protein fragments. The vitamin may be vitamin C or a derivative thereof. The aqueous solution of pure silk fibroin protein fragments may be lyophilized. The method may further comprise adding an alpha-hydroxy acid to the aqueous solution of pure silk fibroin protein fragments. The alpha hydroxy acid may be selected from the group consisting of glycolic acid, lactic acid, tartaric acid and citric acid. The method may further comprise adding hyaluronic acid or its salt form at a concentration of about 0.5% to about 10.0% to the aqueous solution of pure silk fibroin protein fragments. A film may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The film may comprise from about 1.0 wt. % to about 50.0 wt. % of vitamin C or a derivative thereof. The film may have a water content ranging from about 2.0 wt. % to about 20.0 wt. %. The film may comprise from about 30.0 wt. % to about 99.5 wt. % of pure silk fibroin protein fragments. A gel may be fabricated from the aqueous solution of pure silk fibroin protein fragments produced by this method. The gel may comprise from about 0.5 wt. % to about 20.0 wt. % of vitamin C or a derivative thereof. The gel may have a silk content of at least 2 wt. % and a vitamin content of at least 20 wt. %. Molecular weight of the silk protein fragments may be controlled based upon the specific parameters utilized during the extraction step, including extraction time and temperature; specific parameters utilized during the dissolution step, including the LiBr temperature at the time of submersion of the silk in to the lithium bromide and time that the solution is maintained at specific temperatures; and specific parameters utilized during the filtration step. By controlling process parameters using the disclosed methods, it is possible to create silk fibroin protein fragment solutions with polydispersity equal to or lower than 2.5 at a variety of different molecular weight selected from between 5 kDa to 200 kDa, or between 10 kDa and 80 kDa. By altering process parameters to achieve silk solutions with different molecular weights, a range of fragment mixture end products, with desired polydispersity of equal to or less than 2.5 may be targeted based upon the desired performance requirements. For example, a higher molecular weight silk film containing an ophthalmic drug may have a controlled slow release rate compared to a lower molecular weight film making it ideal for a delivery vehicle in eye care products. Additionally, the silk fibroin protein fragment solutions with a polydispersity of greater than 2.5 can be achieved. Further, two solutions with different average molecular weights and polydispersity can be mixed to create combination solutions. Alternatively, a liquid silk gland (100% sericin free silk protein) that has been removed directly from a worm could be used in combination with any of the silk fibroin protein fragment solutions of the present disclosure. Molecular weight of the pure silk fibroin protein fragment composition was determined using High Pressure Liquid Chromatography (HPLC) with a Refractive Index Detector (RID). Polydispersity was calculated using Cirrus GPC Online GPC/SEC Software Version 3.3 (Agilent). Differences in the processing parameters can result in regenerated silk fibroins that vary in molecular weight, and peptide chain size distribution (polydispersity, PD). This, in turn, influences the regenerated silk fibroin performance, including mechanical strength, water solubility etc. Parameters were varied during the processing of raw silk cocoons into the silk solution. Varying these parameters affected the MW of the resulting silk solution. Parameters manipulated included (i) time and temperature of extraction, (ii) temperature of LiBr, (iii) temperature of dissolution oven, and (iv) dissolution time. Experiments were carried out to determine the effect of varying the extraction time. Tables A-G summarize the results. Below is a summary: – A sericin extraction time of 30 minutes resulted in larger molecular weight than a sericin extraction time of 60 minutes – Molecular weight decreases with time in the oven – 140 °C LiBr and oven resulted in the low end of the confidence interval to be below a molecular weight of 9500 Da – 30 min extraction at the 1 hour and 4 hour time points have undigested silk – 30 min extraction at the 1 hour time point resulted in a significantly high molecular weight with the low end of the confidence interval being 35,000 Da – The range of molecular weight reached for the high end of the confidence interval was 18000 to 216000 Da (important for offering solutions with specified upper limit).

Experiments were carried out to determine the effect of varying the extraction temperature. Table G summarizes the results. Below is a summary: – Sericin extraction at 90 °C resulted in higher MW than sericin extraction at 100 °C extraction – Both 90 °C and 100 °C show decreasing MW over time in the oven.

Experiments were carried out to determine the effect of varying the Lithium Bromide (LiBr) temperature when added to silk. Tables H-I summarize the results. Below is a summary: – No impact on molecular weight or confidence interval (all CI ~10500-6500 Da) – Studies illustrated that the temperature of LiBr-silk dissolution, as LiBr is added and begins dissolving, rapidly drops below the original LiBr temperature due to the majority of the mass being silk at room temperature

Experiments were carried out to determine the effect of v oven/dissolution temperature. Tables J-N summarize the results. Below is a summary: – Oven temperature has less of an effect on 60 min extracted silk than 30 min extracted silk. Without wishing to be bound by theory, it is believed that the 30 min silk is less degraded during extraction and therefore the oven temperature has more of an effect on the larger MW, less degraded portion of the silk. – For 60 °C vs.140 °C oven the 30 min extracted silk showed a very significant effect of lower MW at higher oven temp, while 60 min extracted silk had an effect but much less – The 140 °C oven resulted in a low end in the confidence interval at ~6000 Da.

The raw silk cocoons from the silkworm Bombyx mori was cut into pieces. The pieces of raw silk cocoons were boiled in an aqueous solution of Na₂CO₃ (about 100 °C) for a period of time between about 30 minutes to about 60 minutes to remove sericin (degumming). The volume of the water used equals about 0.4 x raw silk weight and the amount of Na₂CO₃ is about 0.848 x the weight of the raw silk cocoon pieces. The resulting degummed silk cocoon pieces were rinsed with deionized water three times at about 60 °C (20 minutes per rinse). The volume of rinse water for each cycle was 0.2 L x the weight of the raw silk cocoon pieces. The excess water from the degummed silk cocoon pieces was removed. After the DI water washing step, the wet degummed silk cocoon pieces were dried at room temperature. The degummed silk cocoon pieces were mixed with a LiBr solution, and the mixture was heated to about 100 °C. The warmed mixture was placed in a dry oven and was heated at a temperature ranging from about 60 °C to about 140 °C for about 60 minutes to achieve complete dissolution of the native silk protein. The resulting solution was allowed to cool to room temperature and then was dialyzed to remove LiBr salts using a 3,500 Da MWCO membrane. Multiple exchanges were performed in Di water until Br⁻ ions were less than 1 ppm as determined in the hydrolyzed fibroin solution read on an Oakton Bromide (Br⁻) double-junction ion-selective electrode. The resulting silk fibroin aqueous solution has a concentration of about 8.0 % w/v containing pure silk fibroin protein fragments having an average weight average molecular weight selected from between about 6 kDa to about 16 kDa, about 17 kDa to about 39 kDa, and about 39 kDa to about 80 kDa and a polydispersity of between about 1.5 and about 3.0. The 8.0 % w/v was diluted with DI water to provide a 1.0 % w/v, 2.0 % w/v, 3.0 % w/v, 4.0 % w/v, 5.0 % w/v by the coating solution. A variety of % silk concentrations have been produced through the use of Tangential Flow Filtration (TFF). In all cases a 1 % silk solution was used as the input feed. A range of 750-18,000 mL of 1% silk solution was used as the starting volume. Solution is diafiltered in the TFF to remove lithium bromide. Once below a specified level of residual LiBr, solution undergoes ultrafiltration to increase the concentration through removal of water. See examples below. Six (6) silk solutions were utilized in standard silk structures with the following results: Solution #1 is a silk concentration of 5.9 wt. %, average MW of 19.8 kDa and 2.2 PDI (made with a 60 min boil extraction, 100 °C LiBr dissolution for 1 hour). Solution #2 is a silk concentration of 6.4 wt. % (made with a 30 min boil extraction, 60 °C LiBr dissolution for 4 hrs). Solution #3 is a silk concentration of 6.17 wt. % (made with a 30 min boil extraction 100 °C LiBr dissolution for 1 hour). Solution #4 is a silk concentration of 7.30 wt. %: A 7.30 % silk solution was produced beginning with 30 minute extraction batches of 100 g silk cocoons per batch. Extracted silk fibers were then dissolved using 100 °C 9.3 M LiBr in a 100 °C oven for 1 hour.100 g of silk fibers were dissolved per batch to create 20% silk in LiBr. Dissolved silk in LiBr was then diluted to 1% silk and filtered through a 5 µm filter to remove large debris.15,500 mL of 1 %, filtered silk solution was used as the starting volume/diafiltration volume for TFF. Once LiBr was removed, the solution was ultrafiltered to a volume around 1300 mL.1262 mL of 7.30 % silk was then collected. Water was added to the feed to help remove the remaining solution and 547 mL of 3.91 % silk was then collected. Solution #5 is a silk concentration of 6.44 wt. %: A 6.44 wt. % silk solution was produced beginning with 60 minute extraction batches of a mix of 25, 33, 50, 75 and 100 g silk cocoons per batch. Extracted silk fibers were then dissolved using 100 °C 9.3 M LiBr in a 100 °C oven for 1 hour. 35, 42, 50 and 71 g per batch of silk fibers were dissolved to create 20 % silk in LiBr and combined. Dissolved silk in LiBr was then diluted to 1 % silk and filtered through a 5 µm filter to remove large debris.17,000 mL of 1 %, filtered silk solution was used as the starting volume/diafiltration volume for TFF. Once LiBr was removed, the solution was ultrafiltered to a volume around 3000 mL.1490 mL of 6.44 % silk was then collected. Water was added to the feed to help remove the remaining solution and 1454 mL of 4.88 % silk was then collected. Solution #6 is a silk concentration of 2.70 wt. %: A 2.70 % silk solution was produced beginning with 60-minute extraction batches of 25 g silk cocoons per batch. Extracted silk fibers were then dissolved using 100 °C 9.3 M LiBr in a 100 °C oven for 1 hour.35.48 g of silk fibers were dissolved per batch to create 20 % silk in LiBr. Dissolved silk in LiBr was then diluted to 1% silk and filtered through a 5 µm filter to remove large debris.1000 mL of 1%, filtered silk solution was used as the starting volume/diafiltration volume for TFF. Once LiBr was removed, the solution was ultrafiltered to a volume around 300 mL.312 mL of 2.7 % silk was then collected. The preparation of silk fibroin solutions with higher molecular weights is given in Table O.

G F_I G D G F_I

Silk aqueous coating composition for application to fabrics are given in Tables P and Q below.

Three (3) silk solutions were utilized in film making with the following results: Solution #1 is a silk concentration of 5.9 %, average MW of 19.8 kDa and 2.2 PD (made with a 60 min boil extraction, 100 °C LiBr dissolution for 1 hr). Solution #2 is a silk concentration of 6.4 % (made with a 30 min boil extraction, 60 °C LiBr dissolution for 4 hrs). Solution #3 is a silk concentration of 6.17 % (made with a 30 min boil extraction, 100 °C LiBr dissolution for 1 hour). Films were made in accordance with Rockwood et al. (Nature Protocols; Vol.6; No. 10; published on-line Sep.22, 2011; doi:10.1038/nprot.2011.379).4 mL of 1% or 2% (wt/vol) aqueous silk solution was added into 100 mm Petri dish (Volume of silk can be varied for thicker or thinner films and is not critical) and allowed to dry overnight uncovered. The bottom of a vacuum desiccator was filled with water. Dry films were placed in the desiccator and vacuum applied, allowing the films to water anneal for 4 hours prior to removal from the dish. Films cast from solution #1 did not result in a structurally continuous film; the film was cracked in several pieces. These pieces of film dissolved in water in spite of the water annealing treatment. Silk solutions of various molecular weights and/or combinations of molecular weights can be optimized for gel applications. The following provides an example of this process but it not intended to be limiting in application or formulation. Three (3) silk solutions were utilized in gel making with the following results: Solution #1 is a silk concentration of 5.9 %, average MW of 19.8 kDa and 2.2 PD (made with a 60 min boil extraction, 100 °C LiBr dissolution for 1 hr). Solution #2 is a silk concentration of 6.4 % (made with a 30 min boil extraction, 60 °C LiBr dissolution for 4 hrs). Solution #3 is a silk concentration of 6.17 % (made with a 30 min boil extraction, 100 °C LiBr dissolution for 1 hour). “Egel” is an electrogelation process as described in Rockwood of al. Briefly, 10 ml of aqueous silk solution is added to a 50 ml conical tube and a pair of platinum wire electrodes immersed into the silk solution. A 20 volt potential was applied to the platinum electrodes for 5 minutes, the power supply turned off and the gel collected. Solution #1 did not form an EGEL over the 5 minutes of applied electric current. Solutions #2 and #3 were gelled in accordance with the published horseradish peroxidase (HRP) protocol. Behavior seemed typical of published solutions. Materials and Methods: the following equipment and material are used in determination of Silk Molecular weight: Agilent 1100 with chemstation software ver.10.01; Refractive Index Detector (RID); analytical balance; volumetric flasks (1000 mL, 10 mL and 5 mL); HPLC grade water; ACS grade sodium chloride; ACS grade sodium phosphate dibasic heptahydrate; phosphoric acid; dextran MW Standards-Nominal Molecular Weights of 5 kDa, 11.6 kDa, 23.8 kDa, 48.6 kDa, and 148 kDa; 50 mL PET or polypropylene disposable centrifuge tubes; graduated pipettes; amber glass HPLC vials with Teflon caps; Phenomenex PolySep GFC P-4000 column (size: 7.8 mm x 300 mm). Procedural Steps: A) Preparation of 1 L Mobile Phase (0.1 M Sodium Chloride solution in 0.0125 M Sodium phosphate buffer) Take a 250 mL clean and dry beaker, place it on the balance and tare the weight. Add about 3.3509 g of sodium phosphate dibasic heptahydrate to the beaker. Note down the exact weight of sodium phosphate dibasic weighed. Dissolve the weighed sodium phosphate by adding 100 mL of HPLC water into the beaker. Take care not to spill any of the content of the beaker. Transfer the solution carefully into a clean and dry 1000 mL volumetric flask. Rinse the beaker and transfer the rinse into the volumetric flask. Repeat the rinse 4-5 times. In a separate clean and dry 250 mL beaker weigh exactly about 5.8440 g of sodium chloride. Dissolve the weighed sodium chloride in 50 mL of water and transfer the solution to the sodium phosphate solution in the volumetric flask. Rinse the beaker and transfer the rinse into the volumetric flask. Adjust the pH of the solution to 7.0 ± 0.2 with phosphoric acid. Make up the volume in volumetric flask with HPLC water to 1000 mL and shake it vigorously to homogeneously mix the solution. Filter the solution through 0.45 µm polyamide membrane filter. Transfer the solution to a clean and dry solvent bottle and label the bottle. The volume of the solution can be varied to the requirement by correspondingly varying the amount of sodium phosphate dibasic heptahydrate and sodium chloride. B) Preparation of Dextran Molecular Weight Standard solutions At least five different molecular weight standards are used for each batch of samples that are run so that the expected value of the sample to be tested is bracketed by the value of the standard used. Label six 20 mL scintillation glass vials respective to the molecular weight standards. Weigh accurately about 5 mg of each of dextran molecular weight standards and record the weights. Dissolve the dextran molecular weight standards in 5 mL of mobile phase to make a 1 mg/mL standard solution. C) Preparation of Sample solutions When preparing sample solutions, if there are limitations on how much sample is available, the preparations may be scaled as long as the ratios are maintained. Depending on sample type and silk protein content in sample weigh enough sample in a 50 mL disposable centrifuge tube on an analytical balance to make a 1 mg/mL sample solution for analysis. Dissolve the sample in equivalent volume of mobile phase make a 1 mg/mL solution. Tightly cap the tubes and mix the samples (in solution). Leave the sample solution for 30 minutes at room temperature. Gently mix the sample solution again for 1 minute and centrifuge at 4000 RPM for 10 minutes. D) HPLC analysis of the samples Transfer 1.0 mL of all the standards and sample solutions into individual HPLC vials. Inject the molecular weight standards (one injection each) and each sample in duplicate. Analyze all the standards and sample solutions using the following HPLC conditions:

E) Data analysis and calculations - Calculation of Average Molecular Weight using Cirrus Software Upload the chromatography data files of the standards and the analytical samples into Cirrus SEC data collection and molecular weight analysis software. Calculate the weight average molecular weight (Mw), number average molecular weight (Mn), peak average molecular weight (M_p), and polydispersity for each injection of the sample. Spider Silk Fragments Spider silks are natural polymers that consist of three domains: a repetitive middle core domain that dominates the protein chain, and non-repetitive N-terminal and C-terminal domains. The large core domain is organized in a block copolymer-like arrangement, in which two basic sequences, crystalline [poly(A) or poly(GA)] and less crystalline (GGX or GPGXX) polypeptides alternate. Dragline silk is the protein complex composed of major ampullate dragline silk protein 1 (MaSp1) and major ampullate dragline silk protein 2 (MaSp2). Both silks are approximately 3500 amino acid long. MaSp1 can be found in the fibre core and the periphery, whereas MaSp2 forms clusters in certain core areas. The large central domains of MaSp1 and MaSp2 are organized in block copolymer-like arrangements, in which two basic sequences, crystalline [poly(A) or poly(GA)] and less crystalline (GGX or GPGXX) polypeptides alternate in core domain. Specific secondary structures have been assigned to poly(A)/(GA), GGX and GPGXX motifs including β-sheet, α-helix and β-spiral respectively. The primary sequence, composition and secondary structural elements of the repetitive core domain are responsible for mechanical properties of spider silks; whereas, non-repetitive N- and C-terminal domains are essential for the storage of liquid silk dope in a lumen and fibre formation in a spinning duct. The main difference between MaSp1 and MaSp2 is the presence of proline (P) residues accounting for 15% of the total amino acid content in MaSp2, whereas MaSp1 is proline-free. By calculating the number of proline residues in N. clavipes dragline silk, it is possible to estimate the presence of the two proteins in fibres; 81% MaSp1 and 19% MaSp2. Different spiders have different ratios of MaSp1 and MaSp2. For example, a dragline silk fibre from the orb weaver Argiope aurantia contains 41% MaSp1 and 59% MaSp2. Such changes in the ratios of major ampullate silks can dictate the performance of the silk fibre. At least seven different types of silk proteins are known for one orb-weaver species of spider. Silks differ in primary sequence, physical properties and functions. For example, dragline silks used to build frames, radii and lifelines are known for outstanding mechanical properties including strength, toughness and elasticity. On an equal weight basis, spider silk has a higher toughness than steel and Kevlar. Flageliform silk found in capture spirals has extensibility of up to 500%. Minor ampullate silk, which is found in auxiliary spirals of the orb-web and in prey wrapping, possesses high toughness and strength almost similar to major ampullate silks, but does not supercontract in water. Spider silks are known for their high tensile strength and toughness. The recombinant silk proteins also confer advantageous properties to cosmetic or dermatological compositions, in particular to be able to improve the hydrating or softening action, good film forming property and low surface density. Diverse and unique biomechanical properties together with biocompatibility and a slow rate of degradation make spider silks excellent candidates as biomaterials for tissue engineering, guided tissue repair and drug delivery, for cosmetic products (e.g. nail and hair strengthener, skin care products), and industrial materials (e.g. nanowires, nanofibers, surface coatings). In an embodiment, a silk protein may include a polypeptide derived from natural spider silk proteins. The polypeptide is not limited particularly as long as it is derived from natural spider silk proteins, and examples of the polypeptide include natural spider silk proteins and recombinant spider silk proteins such as variants, analogs, derivatives or the like of the natural spider silk proteins. In terms of excellent tenacity, the polypeptide may be derived from major dragline silk proteins produced in major ampullate glands of spiders. Examples of the major dragline silk proteins include major ampullate spidroin MaSp1 and MaSp2 from Nephila clavipes, and ADF3 and ADF4 from Araneus diadematus, etc. Examples of the polypeptide derived from major dragline silk proteins include variants, analogs, derivatives or the like of the major dragline silk proteins. Further, the polypeptide may be derived from flagelliform silk proteins produced in flagelliform glands of spiders. Examples of the flagelliform silk proteins include flagelliform silk proteins derived from Nephila clavipes, etc. Examples of the polypeptide derived from major dragline silk proteins include a polypeptide containing two or more units of an amino acid sequence represented by the formula 1: REP1-REP2 (1), preferably a polypeptide containing five or more units thereof, and more preferably a polypeptide containing ten or more units thereof. Alternatively, the polypeptide derived from major dragline silk proteins may be a polypeptide that contains units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) and that has, at a C-terminal, an amino acid sequence represented by any of SEQ ID NOS: 1 to 3 of U.S. Patent No.9,051,453 or an amino acid sequence having a homology of 90% or more with the amino acid sequence represented by any of SEQ ID NOS: 1 to 3 of U.S. Patent No. 9,051,453. In the polypeptide derived from major dragline silk proteins, units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) may be the same or may be different from each other. In the case of producing a recombinant protein using a microbe such as Escherichia coli as a host, the molecular weight of the polypeptide derived from major dragline silk proteins is 500 kDa or less, or 300 kDa or less, or 200 kDa or less, in terms of productivity. In the formula (1), the REP1 indicates polyalanine. In the REP1, the number of alanine residues arranged in succession is preferably 2 or more, more preferably 3 or more, further preferably 4 or more, and particularly preferably 5 or more. Further, in the REP1, the number of alanine residues arranged in succession is preferably 20 or less, more preferably 16 or less, further preferably 12 or less, and particularly preferably 10 or less. In the formula (1), the REP2 is an amino acid sequence composed of 10 to 200 amino acid residues. The total number of glycine, serine, glutamine and alanine residues contained in the amino acid sequence is 40% or more, preferably 60% or more, and more preferably 70% or more with respect to the total number of amino acid residues contained therein. In the major dragline silk, the REP1 corresponds to a crystal region in a fiber where a crystal β sheet is formed, and the REP2 corresponds to an amorphous region in a fiber where most of the parts lack regular configurations and that has more flexibility. Further, the [REP1-REP2] corresponds to a repetitious region (repetitive sequence) composed of the crystal region and the amorphous region, which is a characteristic sequence of dragline silk proteins. Recombinant Silk Fragments In some embodiments, the recombinant silk protein refers to recombinant spider silk polypeptides, recombinant insect silk polypeptides, or recombinant mussel silk polypeptides. In some embodiments, the recombinant silk protein fragment disclosed herein include recombinant spider silk polypeptides of Araneidae or Araneoids, or recombinant insect silk polypeptides of Bombyx mori. In some embodiments, the recombinant silk protein fragment disclosed herein include recombinant spider silk polypeptides of Araneidae or Araneoids. In some embodiments, the recombinant silk protein fragment disclosed herein include block copolymer having repetitive units derived from natural spider silk polypeptides of Araneidae or Araneoids. In some embodiments, the recombinant silk protein fragment disclosed herein include block copolymer having synthetic repetitive units derived from spider silk polypeptides of Araneidae or Araneoids and non-repetitive units derived from natural repetitive units of spider silk polypeptides of Araneidae or Araneoids. Recent advances in genetic engineering have provided a route to produce various types of recombinant silk proteins. Recombinant DNA technology has been used to provide a more practical source of silk proteins. As used herein “recombinant silk protein” refers to synthetic proteins produced heterologously in prokaryotic or eukaryotic expression systems using genetic engineering methods. Various methods for synthesizing recombinant silk peptides are known and have been described by Ausubel et al., Current Protocols in Molecular Biology § 8 (John Wiley & Sons 1987, (1990)), incorporated herein by reference. A gram-negative, rod-shaped bacterium E. coli is a well-established host for industrial scale production of proteins. Therefore, the majority of recombinant silks have been produced in E. coli. E. coli which is easy to manipulate, has a short generation time, is relatively low cost and can be scaled up for larger amounts protein production. The recombinant silk proteins can be produced by transformed prokaryotic or eukaryotic systems containing the cDNA coding for a silk protein, for a fragment of this protein or for an analog of such a protein. The recombinant DNA approach enables the production of recombinant silks with programmed sequences, secondary structures, architectures and precise molecular weight. There are four main steps in the process: (i) design and assembly of synthetic silk-like genes into genetic ‘cassettes’, (ii) insertion of this segment into a DNA recombinant vector, (iii) transformation of this recombinant DNA molecule into a host cell and (iv) expression and purification of the selected clones. The term “recombinant vectors”, as used herein, includes any vectors known to the skilled person including plasmid vectors, cosmid vectors, phage vectors such as lambda phage, viral vectors such as adenoviral or baculoviral vectors, or artificial chromosome vectors such as bacterial artificial chromosomes (BAC), yeast artificial chromosomes (YAC), or P1 artificial chromosomes (PAC). Said vectors include expression as well as cloning vectors. Expression vectors comprise plasmids as well as viral vectors and generally contain a desired coding sequence and appropriate DNA sequences necessary for the expression of the operably linked coding sequence in a particular host organism (e.g., bacteria, yeast, or plant) or in in vitro expression systems. Cloning vectors are generally used to engineer and amplify a certain desired DNA fragment and may lack functional sequences needed for expression of the desired DNA fragments. The prokaryotic systems include Gram-negative bacteria or Gram-positive bacteria. The prokaryotic expression vectors can include an origin of replication which can be recognized by the host organism, a homologous or heterologous promoter which is functional in the said host, the DNA sequence coding for the spider silk protein, for a fragment of this protein or for an analogous protein. Nonlimiting examples of prokaryotic expression organisms are Escherichia coli, Bacillus subtilis, Bacillus megaterium, Corynebacterium glutamicum, Anabaena, Caulobacter, Gluconobacter, Rhodobacter, Pseudomonas, Para coccus, Bacillus (e.g. Bacillus subtilis) Brevibacterium, Corynebacterium, Rhizobium (Sinorhizobium), Flavobacterium, Klebsiella, Enterobacter, Lactobacillus, Lactococcus, Methylobacterium, Propionibacterium, Staphylococcus or Streptomyces cells. The eukaryotic systems include yeasts and insect, mammalian or plant cells. In this case, the expression vectors can include a yeast plasmid origin of replication or an autonomous replication sequence, a promoter, a DNA sequence coding for a spider silk protein, for a fragment or for an analogous protein, a polyadenylation sequence, a transcription termination site and, lastly, a selection gene. Nonlimiting examples of eukaryotic expression organisms include yeasts, such as Saccharomyces cerevisiae, Pichia pastoris, basidiosporogenous, ascosporogenous, filamentous fungi, such as Aspergillus niger, Aspergillus oryzae, Aspergillus nidulans, Trichoderma reesei, Acremonium chrysogenum, Candida, Hansenula, Kluyveromyces, Saccharomyces (e.g. Saccharomyces cerevisiae), Schizosaccharomyces, Pichia (e.g. Pichia pastoris) or Yarrowia cells etc., mammalian cells, such as HeLa cells, COS cells, CHO cells etc., insect cells, such as Sf9 cells, MEL cells, etc., “insect host cells” such as Spodoptera frugiperda or Trichoplusia ni cells. SF9 cells, SF-21 cells or High-Five cells, wherein SF-9 and SF-21 are ovarian cells from Spodoptera frugiperda, and High-Five cells are egg cells from Trichoplusia ni., “plant host cells”, such as tobacco, potato or pea cells. A variety of heterologous host systems have been explored to produce different types of recombinant silks. Recombinant partial spidroins as well as engineered silks have been cloned and expressed in bacteria (Escherichia coli), yeast (Pichia pastoris), insects (silkworm larvae), plants (tobacco, soybean, potato, Arabidopsis), mammalian cell lines (BHT/hamster) and transgenic animals (mice, goats). Most of the silk proteins are produced with an N- or C- terminal His-tags to make purification simple and produce enough amounts of the protein. In some embodiments, the host suitable for expressing the recombinant spider silk protein using heterogeneous system may include transgenic animals and plants. In some embodiments, the host suitable for expressing the recombinant spider silk protein using heterogeneous system comprises bacteria, yeasts, mammalian cell lines. In some embodiments, the host suitable for expressing the recombinant spider silk protein using heterogeneous system comprises E. coli. In some embodiments, the host suitable for expressing the recombinant spider silk protein using heterogeneous system comprises transgenic B. mori silkworm generated using genome editing technologies (e.g. CRISPR). The recombinant silk protein in this disclosure comprises synthetic proteins which are based on repeat units of natural silk proteins. Besides the synthetic repetitive silk protein sequences, these can additionally comprise one or more natural nonrepetitive silk protein sequences. In some embodiments, “recombinant silk protein” refers to recombinant silkworm silk protein or fragments thereof. The recombinant production of silk fibroin and silk sericin has been reported. A variety of hosts are used for the production including E. coli, Sacchromyces cerevisiae, Pseudomonas sp., Rhodopseudomonas sp., Bacillus sp., and Strepomyces. See EP 0230702, which is incorporate by reference herein by its entirety. Provided herein also include design and biological-synthesis of silk fibroin protein- like multiblock polymer comprising GAGAGX hexapeptide (X is A, Y, V or S) derived from the repetitive domain of B. mori silk heavy chain (H chain) In some embodiments, this disclosure provides silk protein-like multiblock polymers derived from the repetitive domain of B. mori silk heavy chain (H chain) comprising the GAGAGS hexapeptide repeating units. The GAGAGS hexapeptide is the core unit of H- chain and plays an important role in the formation of crystalline domains. The silk protein- like multiblock polymers containing the GAGAGS hexapeptide repeating units spontaneously aggregate into β-sheet structures, similar to natural silk fibroin protein, where in the silk protein-like multiblock polymers having any weight average molecular weight described herein. In some embodiments, this disclosure provides silk-peptide like multiblock copolymers composed of the GAGAGS hexapeptide repetitive fragment derived from H chain of B. mori silk heavy chain and mammalian elastin VPGVG motif produced by E. coli. In some embodiments, this disclosure provides fusion silk fibroin proteins composed of the GAGAGS hexapeptide repetitive fragment derived from H chain of B. mori silk heavy chain and GVGVP produced by E. coli, where in the silk protein-like multiblock polymers having any weight average molecular weight described herein. In some embodiments, this disclosure provides B. mori silkworm recombinant proteins composed of the (GAGAGS)16 repetitive fragment. In some embodiments, this disclosure provides recombinant proteins composed of the (GAGAGS)₁₆ repetitive fragment and the non-repetitive (GAGAGS)16 –F-COOH, (GAGAGS)16 –F-F-COOH, (GAGAGS)16 – F-F-F-COOH, (GAGAGS)₁₆ –F-F-F-F-COOH, (GAGAGS)₁₆ –F-F-F-F-F-F-F-F-COOH, (GAGAGS)16 –F-F-F-F–F-F-F-F-F-F-F-F-COOH produced by E. coli, where F has the following amino acid sequence SGFGPVANGGSGEASSESDFGSSGFGPVANASSGEASSESDFAG, and where in the silk protein-like multiblock polymers having any weight average molecular weight described herein. In some embodiments, “recombinant silk protein” refers to recombinant spider silk protein or fragments thereof. The productions of recombinant spider silk proteins based on a partial cDNA clone have been reported. The recombinant spider silk proteins produced as such comprise a portion of the repetitive sequence derived from a dragline spider silk protein, Spidroin 1, from the spider Nephila clavipes. see Xu et al. (Proc. Natl. Acad. Sci. U.S.A., 87:7120–7124 (1990). cDNA clone encoding a portion of the repeating sequence of a second fibroin protein, Spidroin 2, from dragline silk of Nephila clavipes and the recombinant synthesis thereof is described in J. Biol. Chem., 1992, volume 267, pp.19320–19324. The recombinant synthesis of spider silk proteins including protein fragments and variants of Nephila clavipes from transformed E. coli is described in U.S. Pat. Nos.5,728,810 and 5,989,894. cDNA clones encoding minor ampullate spider silk proteins and the expression thereof is described in U.S. Pat. Nos.5,733,771 and 5,756,677. cDNA clone encoding the flagelliform silk protein from an orb-web spinning spider is described in U.S. Pat. No. 5,994,099. U.S. Pat. No.6,268,169 describes the recombinant synthesis of spider silk like proteins derived from the repeating peptide sequence found in the natural spider dragline of Nephila clavipes by E. coli, Bacillus subtilis, and Pichia pastoris recombinant expression systems. WO 03/020916 describes the cDNA clone encoding and recombinant production of spider spider silk proteins having repeative sequences derived from the major ampullate glands of Nephila madagascariensis, Nephila senegalensis, Tetragnatha kauaiensis, Tetragnatha versicolor, Argiope aurantia, Argiope trifasciata, Gasteracantha mammosa, and Latrodectus geometricus, the flagelliform glands of Argiope trifasciata, the ampullate glands of Dolomedes tenebrosus, two sets of silk glands from Plectreurys tristis, and the silk glands of the mygalomorph Euagrus chisoseus. Each of the above reference is incorporated herein by reference in its entirety. In some embodiments, the recombinant spider silk protein is a hybrid protein of a spider silk protein and an insect silk protein, a spider silk protein and collagen, a spider silk protein and resilin, or a spider silk protein and keratin. The spider silk repetitive unit comprises or consists of an amino acid sequence of a region that comprises or consists of at least one peptide motif that repetitively occurs within a naturally occurring major ampullate gland polypeptide, such as a dragline spider silk polypeptide, a minor ampullate gland polypeptide, a flagelliform polypeptide, an aggregate spider silk polypeptide, an aciniform spider silk polypeptide or a pyriform spider silk polypeptide. In some embodiments, the recombinant spider silk protein in this disclosure comprises synthetic spider silk proteins derived from repetitive units of natural spider silk proteins, consensus sequence, and optionally one or more natural non-repetitive spider silk protein sequences. The repeated units of natural spider silk polypeptide may include dragline spider silk polypeptides or flagelliform spider silk polypeptides of Araneidae or Araneoids. As used herein, the spider silk “repetitive unit” comprises or consists of at least one peptide motif that repetitively occurs within a naturally occurring major ampullate gland polypeptide, such as a dragline spider silk polypeptide, a minor ampullate gland polypeptide, a flagelliform polypeptide, an aggregate spider silk polypeptide, an aciniform spider silk polypeptide or a pyriform spider silk polypeptide. A “repetitive unit” refers to a region which corresponds in amino acid sequence to a region that comprises or consists of at least one peptide motif (e.g. AAAAAA) or GPGQQ) that repetitively occurs within a naturally occurring silk polypeptide (e.g. MaSpI, ADF-3, ADF-4, or Flag) (i.e. identical amino acid sequence) or to an amino acid sequence substantially similar thereto (i.e. variational amino acid sequence). A “repetitive unit” having an amino acid sequence which is “substantially similar” to a corresponding amino acid sequence within a naturally occurring silk polypeptide (i.e. wild-type repetitive unit) is also similar with respect to its properties, e.g. a silk protein comprising the “substantially similar repetitive unit” is still insoluble and retains its insolubility. A “repetitive unit” having an amino acid sequence which is “identical” to the amino acid sequence of a naturally occurring silk polypeptide, for example, can be a portion of a silk polypeptide corresponding to one or more peptide motifs of MaSpI, MaSpII, ADF-3 and/or ADF-4. A “repetitive unit” having an amino acid sequence which is “substantially similar” to the amino acid sequence of a naturally occurring silk polypeptide, for example, can be a portion of a silk polypeptide corresponding to one or more peptide motifs of MaSpI, MaSpII, ADF-3 and/or ADF-4, but having one or more amino acid substitution at specific amino acid positions. As used herein, the term “consensus peptide sequence” refers to an amino acid sequence which contains amino acids which frequently occur in a certain position (e.g. “G”) and wherein, other amino acids which are not further determined are replaced by the place holder “X”. In some embodiments, the consensus sequence is at least one of (i) GPGXX, wherein X is an amino acid selected from A, S, G, Y, P and Q; (ii) GGX, wherein X is an amino acid selected from Y, P, R, S, A, T, N and Q, preferably Y, P and Q; (iii) Ax, wherein x is an integer from 5 to 10. The consensus peptide sequences GPGXX and GGX, i.e. glycine rich motifs, provide flexibility to the silk polypeptide and thus, to the thread formed from the silk protein containing said motifs. In detail, the iterated GPGXX motif forms turn spiral structures, which imparts elasticity to the silk polypeptide. Major ampullate and flagelliform silks both have a GPGXX motif. The iterated GGX motif is associated with a helical structure having three amino acids per turn and is found in most spider silks. The GGX motif may provide additional elastic properties to the silk. The iterated polyalanine Ax (peptide) motif forms a crystalline β-sheet structure that provides strength to the silk polypeptide, as described for example in WO 03/057727. In some embodiments, the recombinant spider silk protein in this disclosure comprises two identical repetitive units each comprising at least one, preferably one, amino acid sequence selected from the group consisting of: GGRPSDTYG and GGRPSSSYG derived from Resilin. Resilin is an elastomeric protein found in most arthropods that provides low stiffness and high strength. As used herein, “non-repetitive units” refers to an amino acid sequence which is “substantially similar” to a corresponding non-repetitive (carboxy terminal) amino acid sequence within a naturally occurring dragline polypeptide (i.e. wild-type non-repetitive (carboxy terminal) unit), preferably within ADF-3 (SEQ ID NO:1), ADF-4 (SEQ ID NO:2), NR3 (SEQ ID NO:41), NR4 (SEQ ID NO:42), ADF-4 of the spider Araneus diadematus as described in U.S. Pat. No.8,367,803, C16 peptide (spider silk protein eADF4, molecular weight of 47.7 kDa, AMSilk) comprising the 16 repeats of the sequence GSSAAAAAAAASGPGGYGPENQGPSGPGGYGPGGP, an amino acid sequence adapted from the natural sequence of ADF4 from A. diadematus. Non-repetitive ADF-4 and variants thereof display efficient assembly behavior. Among the synthetic spider silk proteins, the recombinant silk protein in this disclosure comprises in some embodiments the C16-protein having the polypeptide sequence SEQ ID NO: 1 as described in U.S. Patent No.8288512. Besides the polypeptide sequence shown in SEQ ID NO:1, particularly functional equivalents, functional derivatives and salts of this sequence are also included. As used herein, “functional equivalents” refers to mutant which, in at least one sequence position of the abovementioned amino acid sequences, have an amino acid other than that specifically mentioned. In some embodiments, the recombinant spider silk protein in this disclosure comprises, in an effective amount, at least one natural or recombinant silk protein including spider silk protein, corresponding to Spidroin major 1 described by Xu et al., PNAS, USA, 87, 7120, (1990), Spidroin major 2 described by Hinman and Lewis, J. Biol. Chem., 267, 19320, (1922), recombinant spider silk protein as described in U.S. Patent Application No. 2016/0222174 and U.S. Patent Nos.9,051,453, 9,617,315, 9,689,089, 8,173,772, 8,642,734, 8,367,8038,097,583, 8,030,024, 7,754,851, 7,148,039, 7,060,260, or alternatively the minor Spidroins described in patent application WO 95/25165. Each of the above-cited references is incorporated herein by reference in its entirety. Additional recombinant spider silk proteins suitable for the recombinant RSPF of this disclosure include ADF3 and ADF4 from the “Major Ampullate” gland of Araneus diadematus. Recombinant silk is also described in other patents and patent applications, incorporated by reference herein: US 2004590196, US 7,754,851, US 2007654470, US 7,951,908, US 2010785960, US 8,034,897, US 20090263430, US 2008226854, US 20090123967, US 2005712095, US 2007991037, US 20090162896, US 200885266, US 8,372,436, US 2007989907, US 2009267596, US 2010319542, US 2009265344, US 2012684607, US 2004583227, US 8,030,024, US 2006643569, US 7,868,146, US 2007991916, US 8,097,583, US 2006643200, US 8,729,238, US 8,877,903, US 20190062557, US 20160280960, US 20110201783, US 2008991916, US 2011986662, US 2012697729, US 20150328363, US 9,034,816, US 20130172478, US 9,217,017, US 20170202995, US 8,721,991, US 2008227498, US 9,233,067, US 8,288,512, US 2008161364, US 7,148,039, US 1999247806, US 2001861597, US 2004887100, US 9,481,719, US 8,765,688, US 200880705, US 2010809102, US 8,367,803, US 2010664902, US 7,569,660, US 1999138833, US 2000591632, US 20120065126, US 20100278882, US 2008161352, US 20100015070, US 2009513709, US 20090194317, US 2004559286, US 200589551, US 2008187824, US 20050266242, US 20050227322, and US 20044418. Recombinant silk is also described in other patents and patent applications, incorporated by reference herein: US 20190062557, US 20150284565, US 20130225476, US 20130172478, US 20130136779, US 20130109762, US 20120252294, US 20110230911, US 20110201783, US 20100298877, US 10,478,520, US 10,253,213, US 10,072,152, US 9,233,067, US 9,217,017, US 9,034,816, US 8,877,903, US 8,729,238, US 8,721,991, US 8,097,583, US 8,034,897, US 8,030,024, US 7,951,908, US 7,868,146, and US 7,754,851. In some embodiments, the recombinant spider silk protein in this disclosure comprises or consists of 2 to 80 repetitive units, each independently selected from GPGXX, GGX and Ax as defined herein. In some embodiments, the recombinant spider silk protein in this disclosure comprises or consists of repetitive units each independently selected from selected from the group consisting of GPGAS, GPGSG, GPGGY, GPGGP, GPGGA, GPGQQ, GPGGG, GPGQG, GPGGS, GGY, GGP, GGA, GGR, GGS, GGT, GGN, GGQ, AAAAA, AAAAAA, AAAAAAA, AAAAAAAA, AAAAAAAAA, AAAAAAAAAA, GGRPSDTYG and GGRPSSSYG, (i) GPYGPGASAAAAAAGGYGPGSGQQ, (ii) GSSAAAAAAAASGPGGYGPENQGPSGPGGYGPGGP, (iii) GPGQQGPGQQGPGQQGPGQQ: (iv) GPGGAGGPYGPGGAGGPYGPGGAGGPY, (v) GGTTIIEDLDITIDGADGPITISEELTI, (vi) PGSSAAAAAAAASGPGQGQGQGQGQGGRPSDTYG, (vii) SAAAAAAAAGPGGGNGGRPSDTYGAPGGGNGGRPSSSYG, (viii) GGAGGAGGAGGSGGAGGS (SEQ ID NO: 27), (ix) GPGGAGPGGYGPGGSGPGGYGPGGSGPGGY, (x) GPYGPGASAAAAAAGGYGPGCGQQ, (xi) GPYGPGASAAAAAAGGYGPGKGQQ, (xii) GSSAAAAAAAASGPGGYGPENQGPCGPGGYGPGGP, (xiii) GSSAAAAAAAASGPGGYGPKNQGPSGPGGYGPGGP, (xiv) GSSAAAAAAAASGPGGYGPKNQGPSGPGGYGPGGP, or variants thereof as described in U.S. Pat. No.8,877,903, for example, a synthetic spider peptide having sequential order of GPGAS, GGY, GPGSG in the peptide chain, or sequential order of AAAAAAAA, GPGGY, GPGGP in the peptide chain, sequential order of AAAAAAAA, GPGQG, GGR in the peptide chain. In some embodiments, this disclosure provides silk protein-like multiblock peptides that imitate the repeating units of amino acids derived from natural spider silk proteins such as Spidroin major 1 domain, Spidroin major 2 domain or Spidroin minor 1 domain and the profile of variation between the repeating units without modifying their three-dimensional conformation, wherein these silk protein-like multiblock peptides comprise a repeating unit of amino acids corresponding to one of the sequences (I), (II), (III) and/or (IV) below. [(XGG)w(XGA)(GXG)x(AGA)y(G)zAG]p Formula (I) in which: X corresponds to tyrosine or to glutamine, w is an integer equal to 2 or 3, x is an integer from 1 to 3, y is an integer from 5 to 7, z is an integer equal to 1 or 2, and p is an integer and having any weight average molecular weight described herein, and/or [(GPG2YGPGQ2)a(X’)2S(A)b]p Formula (II) in which: X’ corresponds to the amino acid sequence GPS or GPG, a is equal to 2 or 3, b is an integer from 7 to 10, and p is an integer and having any weight average molecular weight described herein, and/or [(GR)(GA)_l(A)_m(GGX)_n(GA)_l(A)_m]_p Formula (III) and/or [(GGX)_n(GA)_m(A)_l]_p Formula (IV) in which: X” corresponds to tyrosine, glutamine or alanine, l is an integer from 1 to 6, m is an integer from 0 to 4, n is an integer from 1 to 4, and p is an integer. In some embodiments, the recombinant spider silk protein or an analog of a spider silk protein comprising an amino acid repeating unit of sequence (V): [(Xaa Gly Gly)w(Xaa Gly Ala)(Gly Xaa Gly)x(Ala Gly Ala)y(Gly)zAla Gly]p Formula (V), wherein Xaa is tyrosine or glutamine, w is an integer equal to 2 or 3, x is an integer from 1 to 3, y is an integer from 5 to 7, z is an integer equal to 1 or 2, and p is an integer. In some embodiments, the recombinant spider silk protein in this disclosure is selected from the group consisting of ADF-3 or variants thereof, ADF-4 or variants thereof, MaSpI (SEQ ID NO: 43) or variants thereof, MaSpII (SEQ ID NO: 44) or variants thereof as described in U.S. Pat. No.8,367,803. In some embodiments, this disclosure provides water soluble recombinant spider silk proteins produced in mammalian cells. The solubility of the spider silk proteins produced in mammalian cells was attributed to the presence of the COOH-terminus in these proteins, which makes them more hydrophilic. These COOH-terminal amino acids are absent in spider silk proteins expressed in microbial hosts. In some embodiments, the recombinant spider silk protein in this disclosure comprises water soluble recombinant spider silk protein C16 modified with an amino or carboxyl terminal selected from the amino acid sequences consisting of: GCGGGGGG, GKGGGGGG, GCGGSGGGGSGGGG, GKGGGGGGSGGGG, and GCGGGGGGSGGGG. In some embodiments, the recombinant spider silk protein in this disclosure comprises C₁₆NR4, C32NR4, C16, C32, NR4C16NR4, NR4C32NR4, NR3C16NR3, or NR3C32NR3 such that the molecular weight of the protein ranges as described herein. In some embodiments, the recombinant spider silk protein in this disclosure comprises recombinant spider silk protein having a synthetic repetitive peptide segments and an amino acid sequence adapted from the natural sequence of ADF4 from A. diadematus as described in U.S. Pat. No.8,877,903. In some embodiments, the RSPF in this disclosure comprises the recombinant spider silk proteins having repeating peptide units derived from natural spider silk proteins such as Spidroin major 1 domain, Spidroin major 2 domain or Spidroin minor 1 domain, wherein the repeating peptide sequence is GSSAAAAAAAASGPGQGQGQGQGQGGRPSDTYG or SAAAAAAAAGPGGGNGGRPSDTYGAPGGGNGGRPSSSYG, as described in U.S. Pat. No.8,367,803. In some embodiments, this disclosure provides recombinant spider proteins composed of the GPGGAGPGGYGPGGSGPGGYGPGGSGPGGY repetitive fragment and having a molecular weight as described herein. As used herein, the term “recombinant silk” refers to recombinant spider and/or silkworm silk protein or fragments thereof. In an embodiment, the spider silk protein is selected from the group consisting of swathing silk (Achniform gland silk), egg sac silk (Cylindriform gland silk), egg case silk (Tubuliform silk), non-sticky dragline silk (Ampullate gland silk), attaching thread silk (Pyriform gland silk), sticky silk core fibers (Flagelliform gland silk), and sticky silk outer fibers (Aggregate gland silk). For example, recombinant spider silk protein, as described herein, includes the proteins described in U.S. Patent Application No.2016/0222174 and U.S. Patent Nos.9,051,453, 9,617,315, 9,689,089, 8,173,772, and 8,642,734. Some organisms make multiple silk fibers with unique sequences, structural elements, and mechanical properties. For example, orb weaving spiders have six unique types of glands that produce different silk polypeptide sequences that are polymerized into fibers tailored to fit an environmental or lifecycle niche. The fibers are named for the gland they originate from and the polypeptides are labeled with the gland abbreviation (e.g. “Ma”) and “Sp” for spidroin (short for spider fibroin). In orb weavers, these types include Major Ampullate (MaSp, also called dragline), Minor Ampullate (MiSp), Flagelliform (Flag), Aciniform (AcSp), Tubuliform (TuSp), and Pyriform (PySp). This combination of polypeptide sequences across fiber types, domains, and variation amongst different genus and species of organisms leads to a vast array of potential properties that can be harnessed by commercial production of the recombinant fibers. To date, the vast majority of the work with recombinant silks has focused on the Major Ampullate Spidroins (MaSp). Aciniform (AcSp) silks tend to have high toughness, a result of moderately high strength coupled with moderately high extensibility. AcSp silks are characterized by large block (“ensemble repeat”) sizes that often incorporate motifs of poly serine and GPX. Tubuliform (TuSp or Cylindrical) silks tend to have large diameters, with modest strength and high extensibility. TuSp silks are characterized by their poly serine and poly threonine content, and short tracts of poly alanine. Major Ampullate (MaSp) silks tend to have high strength and modest extensibility. MaSp silks can be one of two subtypes: MaSp1 and MaSp2. MaSp1 silks are generally less extensible than MaSp2 silks, and are characterized by poly alanine, GX, and GGX motifs. MaSp2 silks are characterized by poly alanine, GGX, and GPX motifs. Minor Ampullate (MiSp) silks tend to have modest strength and modest extensibility. MiSp silks are characterized by GGX, GA, and poly A motifs, and often contain spacer elements of approximately 100 amino acids. Flagelliform (Flag) silks tend to have very high extensibility and modest strength. Flag silks are usually characterized by GPG, GGX, and short spacer motifs. Silk polypeptides are characteristically composed of a repeat domain (REP) flanked by non-repetitive regions (e.g., C-terminal and N-terminal domains). In an embodiment, both the C-terminal and N-terminal domains are between 75-350 amino acids in length. The repeat domain exhibits a hierarchical architecture. The repeat domain comprises a series of blocks (also called repeat units). The blocks are repeated, sometimes perfectly and sometimes imperfectly (making up a quasi-repeat domain), throughout the silk repeat domain. The length and composition of blocks varies among different silk types and across different species. Table 1 of U.S. Published Application No.2016/0222174, the entirety of which is incorporated herein, lists examples of block sequences from selected species and silk types, with further examples presented in Rising, A. et al., Spider silk proteins: recent advances in recombinant production, structure-function relationships and biomedical applications, Cell Mol. Life Sci., 68:2, pg 169-184 (2011); and Gatesy, J. et al., Extreme diversity, conservation, and convergence of spider silk fibroin sequences, Science, 291:5513, pg.2603-2605 (2001). In some cases, blocks may be arranged in a regular pattern, forming larger macro-repeats that appear multiple times (usually 2-8) in the repeat domain of the silk sequence. Repeated blocks inside a repeat domain or macro-repeat, and repeated macro-repeats within the repeat domain, may be separated by spacing elements. The construction of certain spider silk block copolymer polypeptides from the blocks and/or macro-repeat domains, according to certain embodiments of the disclosure, is illustrated in U.S. Published Patent Application No.2016/0222174. The recombinant block copolymer polypeptides based on spider silk sequences produced by gene expression in a recombinant prokaryotic or eukaryotic system can be purified according to methods known in the art. In a preferred embodiment, a commercially available expression/secretion system can be used, whereby the recombinant polypeptide is expressed and thereafter secreted from the host cell, to be easily purified from the surrounding medium. If expression/secretion vectors are not used, an alternative approach involves purifying the recombinant block copolymer polypeptide from cell lysates (remains of cells following disruption of cellular integrity) derived from prokaryotic or eukaryotic cells in which a polypeptide was expressed. Methods for generation of such cell lysates are known to those of skill in the art. In some embodiments, recombinant block copolymer polypeptides are isolated from cell culture supernatant. Recombinant block copolymer polypeptide may be purified by affinity separation, such as by immunological interaction with antibodies that bind specifically to the recombinant polypeptide or nickel columns for isolation of recombinant polypeptides tagged with 6-8 histidine residues at their N-terminus or C-terminus Alternative tags may comprise the FLAG epitope or the hemagglutinin epitope. Such methods are commonly used by skilled practitioners. A solution of such polypeptides (i.e., recombinant silk protein) may then be prepared and used as described herein. In another embodiment, recombinant silk protein may be prepared according to the methods described in U.S. Patent No.8,642,734, the entirety of which is incorporated herein, and used as described herein. In an embodiment, a recombinant spider silk protein is provided. The spider silk protein typically consists of from 170 to 760 amino acid residues, such as from 170 to 600 amino acid residues, preferably from 280 to 600 amino acid residues, such as from 300 to 400 amino acid residues, more preferably from 340 to 380 amino acid residues. The small size is advantageous because longer spider silk proteins tend to form amorphous aggregates, which require use of harsh solvents for solubilization and polymerization. The recombinant spider silk protein may contain more than 760 residues, in particular in cases where the spider silk protein contains more than two fragments derived from the N-terminal part of a spider silk protein, The spider silk protein comprises an N-terminal fragment consisting of at least one fragment (NT) derived from the corresponding part of a spider silk protein, and a repetitive fragment (REP) derived from the corresponding internal fragment of a spider silk protein. Optionally, the spider silk protein comprises a C-terminal fragment (CT) derived from the corresponding fragment of a spider silk protein. The spider silk protein comprises typically a single fragment (NT) derived from the N-terminal part of a spider silk protein, but in preferred embodiments, the N-terminal fragment include at least two, such as two fragments (NT) derived from the N-terminal part of a spider silk protein. Thus, the spidroin can schematically be represented by the formula NTm-REP, and alternatively NTm-REP-CT, where m is an integer that is 1 or higher, such as 2 or higher, preferably in the ranges of 1-2, 1-4, 1-6, 2-4 or 2-6. Preferred spidroins can schematically be represented by the formulas NT₂-REP or NT-REP, and alternatively NT₂-REP-CT or NT-REP-CT. The protein fragments are covalently coupled, typically via a peptide bond. In one embodiment, the spider silk protein consists of the NT fragment(s) coupled to the REP fragment, which REP fragment is optionally coupled to the CT fragment. In one embodiment, the first step of the method of producing polymers of an isolated spider silk protein involves expression of a polynucleic acid molecule which encodes the spider silk protein in a suitable host, such as Escherichia coli. The thus obtained protein is isolated using standard procedures. Optionally, lipopolysaccharides and other pyrogens are actively removed at this stage. In the second step of the method of producing polymers of an isolated spider silk protein, a solution of the spider silk protein in a liquid medium is provided. By the terms “soluble” and “in solution” is meant that the protein is not visibly aggregated and does not precipitate from the solvent at 60,000×g. The liquid medium can be any suitable medium, such as an aqueous medium, preferably a physiological medium, typically a buffered aqueous medium, such as a 10-50 mM Tris-HCl buffer or phosphate buffer. The liquid medium has a pH of 6.4 or higher and/or an ion composition that prevents polymerization of the spider silk protein. That is, the liquid medium has either a pH of 6.4 or higher or an ion composition that prevents polymerization of the spider silk protein, or both. Ion compositions that prevent polymerization of the spider silk protein can readily be prepared by the skilled person utilizing the methods disclosed herein. A preferred ion composition that prevents polymerization of the spider silk protein has an ionic strength of more than 300 mM. Specific examples of ion compositions that prevent polymerization of the spider silk protein include above 300 mM NaCl, 100 mM phosphate and combinations of these ions having desired preventive effect on the polymerization of the spider silk protein, e.g. a combination of 10 mM phosphate and 300 mM NaCl. The presence of an NT fragment improves the stability of the solution and prevents polymer formation under these conditions. This can be advantageous when immediate polymerization may be undesirable, e.g. during protein purification, in preparation of large batches, or when other conditions need to be optimized. It is preferred that the pH of the liquid medium is adjusted to 6.7 or higher, such as 7.0 or higher, or even 8.0 or higher, such as up to 10.5, to achieve high solubility of the spider silk protein. It can also be advantageous that the pH of the liquid medium is adjusted to the range of 6.4-6.8, which provides sufficient solubility of the spider silk protein but facilitates subsequent pH adjustment to 6.3 or lower. In the third step, the properties of the liquid medium are adjusted to a pH of 6.3 or lower and ion composition that allows polymerization. That is, if the liquid medium wherein the spider silk protein is dissolved has a pH of 6.4 or higher, the pH is decreased to 6.3 or lower. The skilled person is well aware of various ways of achieving this, typically involving addition of a strong or weak acid. If the liquid medium wherein the spider silk protein is dissolved has an ion composition that prevents polymerization, the ion composition is changed so as to allow polymerization. The skilled person is well aware of various ways of achieving this, e.g. dilution, dialysis or gel filtration. If required, this step involves both decreasing the pH of the liquid medium to 6.3 or lower and changing the ion composition so as to allow polymerization. It is preferred that the pH of the liquid medium is adjusted to 6.2 or lower, such as 6.0 or lower. In particular, it may be advantageous from a practical point of view to limit the pH drop from 6.4 or 6.4-6.8 in the preceding step to 6.3 or 6.0-6.3, e.g.6.2 in this step. In a preferred embodiment, the pH of the liquid medium of this step is 3 or higher, such as 4.2 or higher. The resulting pH range, e.g.4.2-6.3 promotes rapid polymerization, In the fourth step, the spider silk protein is allowed to polymerize in the liquid medium having pH of 6.3 or lower and an ion composition that allows polymerization of the spider silk protein. Although the presence of the NT fragment improves solubility of the spider silk protein at a pH of 6.4 or higher and/or an ion composition that prevents polymerization of the spider silk protein, it accelerates polymer formation at a pH of 6.3 or lower when the ion composition allows polymerization of the spider silk protein. The resulting polymers are preferably solid and macroscopic, and they are formed in the liquid medium having a pH of 6.3 or lower and an ion composition that allows polymerization of the spider silk protein. In a preferred embodiment, the pH of the liquid medium of this step is 3 or higher, such as 4.2 or higher. The resulting pH range, e.g.4.2-6.3 promotes rapid polymerization, Resulting polymer may be provided at the molecular weights described herein and prepared as a solution form that may be used as necessary for article coatings. Ion compositions that allow polymerization of the spider silk protein can readily be prepared by the skilled person utilizing the methods disclosed herein. A preferred ion composition that allows polymerization of the spider silk protein has an ionic strength of less than 300 mM. Specific examples of ion compositions that allow polymerization of the spider silk protein include 150 mM NaCl, 10 mM phosphate, 20 mM phosphate and combinations of these ions lacking preventive effect on the polymerization of the spider silk protein, e.g. a combination of 10 mM phosphate or 20 mM phosphate and 150 mM NaCl. It is preferred that the ionic strength of this liquid medium is adjusted to the range of 1-250 mM. Without desiring to be limited to any specific theory, it is envisaged that the NT fragments have oppositely charged poles, and that environmental changes in pH affects the charge balance on the surface of the protein followed by polymerization, whereas salt inhibits the same event. At neutral pH, the energetic cost of burying the excess negative charge of the acidic pole may be expected to prevent polymerization. However, as the dimer approaches its isoelectric point at lower pH, attractive electrostatic forces will eventually become dominant, explaining the observed salt and pH-dependent polymerization behavior of NT and NT- containing minispidroins. It is proposed that, in some embodiments, pH-induced NT polymerization, and increased efficiency of fiber assembly of NT-minispidroins, are due to surface electrostatic potential changes, and that clustering of acidic residues at one pole of NT shifts its charge balance such that the polymerization transition occurs at pH values of 6.3 or lower. In a fifth step, the resulting, preferably solid spider silk protein polymers are isolated from said liquid medium. Optionally, this step involves actively removing lipopolysaccharides and other pyrogens from the spidroin polymers. Without desiring to be limited to any specific theory, it has been observed that formation of spidroin polymers progresses via formation of water-soluble spidroin dimers. The present disclosure thus also provides a method of producing dimers of an isolated spider silk protein, wherein the first two method steps are as described above. The spider silk proteins are present as dimers in a liquid medium at a pH of 6.4 or higher and/or an ion composition that prevents polymerization of said spider silk protein. The third step involves isolating the dimers obtained in the second step, and optionally removal of lipopolysaccharides and other pyrogens. In a preferred embodiment, the spider silk protein polymer of the disclosure consists of polymerized protein dimers. The present disclosure thus provides a novel use of a spider silk protein, preferably those disclosed herein, for producing dimers of the spider silk protein. According to another aspect, the disclosure provides a polymer of a spider silk protein as disclosed herein. In an embodiment, the polymer of this protein is obtainable by any one of the methods therefor according to the disclosure. Thus, the disclosure provides various uses of recombinant spider silk protein, preferably those disclosed herein, for producing polymers of the spider silk protein as recombinant silk based coatings. According to one embodiment, the present disclosure provides a novel use of a dimer of a spider silk protein, preferably those disclosed herein, for producing polymers of the isolated spider silk protein as recombinant silk based coatings. In these uses, it is preferred that the polymers are produced in a liquid medium having a pH of 6.3 or lower and an ion composition that allows polymerization of said spider silk protein. In an embodiment, the pH of the liquid medium is 3 or higher, such as 4.2 or higher. The resulting pH range, e.g.4.2-6.3 promotes rapid polymerization, Using the method(s) of the present disclosure, it is possible to control the polymerization process, and this allows for optimization of parameters for obtaining silk polymers with desirable properties and shapes. In an embodiment, the recombinant silk proteins described herein, include those described in U.S. patent No.8,642,734, the entirety of which is incorporated by reference. In another embodiment, the recombinant silk proteins described herein may be prepared according to the methods described in U.S. Patent No.9,051,453, the entirety of which is incorporated herein by reference. An amino acid sequence represented by SEQ ID NO: 1 of U.S. Patent No.9,051,453 is identical to an amino acid sequence that is composed of 50 amino acid residues of an amino acid sequence of ADF3 at the C-terminal (NCBI Accession No.: AAC47010, GI: 1263287). An amino acid sequence represented by SEQ ID NO: 2 of U.S. Patent No. 9,051,453 is identical to an amino acid sequence represented by SEQ ID NO: 1 of U.S. Patent No.9,051,453 from which 20 residues have been removed from the C-terminal. An amino acid sequence represented by SEQ ID NO: 3 of U.S. Patent No.9,051,453 is identical to an amino acid sequence represented by SEQ ID NO: 1 from which 29 residues have been removed from the C-terminal. An example of the polypeptide that contains units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) and that has, at a C-terminal, an amino acid sequence represented by any of SEQ ID NOS: 1 to 3 or an amino acid sequence having a homology of 90% or more with the amino acid sequence represented by any of SEQ ID NOS: 1 to 3 of U.S. Patent No.9,051,453 is a polypeptide having an amino acid sequence represented by SEQ ID NO: 8 of U.S. Patent No.9,051,453. The polypeptide having the amino acid sequence represented by SEQ ID NO: 8 of U.S. Patent No.9,051,453 is obtained by the following mutation: in an amino acid sequence of ADF3 (NCBI Accession No.: AAC47010, GI: 1263287) to the N-terminal of which has been added an amino acid sequence (SEQ ID NO: 5 of U.S. Patent No.9,051,453) composed of a start codon, His 10 tags and an HRV3C Protease (Human rhinovirus 3C Protease) recognition site, 1^st to 13^th repetitive regions are about doubled and the translation ends at the 1154^th amino acid residue. In the polypeptide having the amino acid sequence represented by SEQ ID NO: 8 of U.S. Patent No. 9,051,453, the C-terminal sequence is identical to the amino acid sequence represented by SEQ ID NO: 3. Further, the polypeptide that contains units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) and that has, at a C-terminal, an amino acid sequence represented by any of SEQ ID NOS: 1 to 3 of U.S. Patent No.9,051,453 or an amino acid sequence having a homology of 90% or more with the amino acid sequence represented by any of SEQ ID NOS: 1 to 3 of U.S. Patent No.9,051,453 may be a protein that has an amino acid sequence represented by SEQ ID NO: 8 of U.S. Patent No.9,051,453 in which one or a plurality of amino acids have been substituted, deleted, inserted and/or added and that has a repetitious region composed of a crystal region and an amorphous region. Further, an example of the polypeptide containing two or more units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) is a recombinant protein derived from ADF4 having an amino acid sequence represented by SEQ ID NO: 15 of U.S. Patent No.9,051,453. The amino acid sequence represented by SEQ ID NO: 15 of U.S. Patent No. 9,051,453 is an amino acid sequence obtained by adding the amino acid sequence (SEQ ID NO: 5 of U.S. Patent No.9,051,453) composed of a start codon, His 10 tags and an HRV3C Protease (Human rhinovirus 3C Protease) recognition site, to the N-terminal of a partial amino acid sequence of ADF4 obtained from the NCBI database (NCBI Accession No.: AAC47011, GI: 1263289). Further, the polypeptide containing two or more units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) may be a polypeptide that has an amino acid sequence represented by SEQ ID NO: 15 of U.S. Patent No.9,051,453 in which one or a plurality of amino acids have been substituted, deleted, inserted and/or added and that has a repetitious region composed of a crystal region and an amorphous region. Further, an example of the polypeptide containing two or more units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) is a recombinant protein derived from MaSp2 that has an amino acid sequence represented by SEQ ID NO: 17 of U.S. Patent No.9,051,453. The amino acid sequence represented by SEQ ID NO: 17 of U.S. Patent No. 9,051,453 is an amino acid sequence obtained by adding the amino acid sequence (SEQ ID NO: 5 of U.S. Patent No.9,051,453) composed of a start codon, His 10 tags and an HRV3C Protease (Human rhinovirus 3C Protease) recognition site, to the N-terminal of a partial sequence of MaSp2 obtained from the NCBI web database (NCBI Accession No.: AAT75313, GI: 50363147). Furthermore, the polypeptide containing two or more units of the amino acid sequence represented by the formula 1: REP1-REP2 (1) may be a polypeptide that has an amino acid sequence represented by SEQ ID NO: 17 of U.S. Patent No.9,051,453 in which one or a plurality of amino acids have been substituted, deleted, inserted and/or added and that has a repetitious region composed of a crystal region and an amorphous region. Examples of the polypeptide derived from flagelliform silk proteins include a polypeptide containing 10 or more units of an amino acid sequence represented by the formula 2: REP3 (2), preferably a polypeptide containing 20 or more units thereof, and more preferably a polypeptide containing 30 or more units thereof. In the case of producing a recombinant protein using a microbe such as Escherichia coli as a host, the molecular weight of the polypeptide derived from flagelliform silk proteins is preferably 500 kDa or less, more preferably 300 kDa or less, and further preferably 200 kDa or less, in terms of productivity. In the formula (2), the REP 3 indicates an amino acid sequence composed of Gly-Pro- Gly-Gly-X, where X indicates an amino acid selected from the group consisting of Ala, Ser, Tyr and Val. A major characteristic of the spider silk is that the flagelliform silk does not have a crystal region, but has a repetitious region composed of an amorphous region. Since the major dragline silk and the like have a repetitious region composed of a crystal region and an amorphous region, they are expected to have both high stress and stretchability. Meanwhile, as to the flagelliform silk, although the stress is inferior to that of the major dragline silk, the stretchability is high. The reason for this is considered to be that most of the flagelliform silk is composed of amorphous regions. An example of the polypeptide containing 10 or more units of the amino acid sequence represented by the formula 2: REP3 (2) is a recombinant protein derived from flagelliform silk proteins having an amino acid sequence represented by SEQ ID NO: 19 of U.S. Patent No.9,051,453. The amino acid sequence represented by SEQ ID NO: 19 of U.S. Patent No.9,051,453 is an amino acid sequence obtained by combining a partial sequence of flagelliform silk protein of Nephila clavipes obtained from the NCBI database (NCBI Accession No.: AAF36090, GI: 7106224), specifically, an amino acid sequence thereof from the 1220^th residue to the 1659^th residue from the N-terminal that corresponds to repetitive sections and motifs (referred to as a PR1 sequence), with a partial sequence of flagelliform silk protein of Nephila clavipes obtained from the NCBI database (NCBI Accession No.: AAC38847, GI: 2833649), specifically, a C-terminal amino acid sequence thereof from the 816^th residue to the 907^th residue from the C-terminal, and thereafter adding the amino acid sequence (SEQ ID NO: 5 of U.S. Patent No.9,051,453) composed of a start codon, His 10 tags and an HRV3C Protease recognition site, to the N-terminal of the combined sequence. Further, the polypeptide containing 10 or more units of the amino acid sequence represented by the formula 2: REP3 (2) may be a polypeptide that has an amino acid sequence represented by SEQ ID NO: 19 of U.S. Patent No.9,051,453 in which one or a plurality of amino acids have been substituted, deleted, inserted and/or added and that has a repetitious region composed of an amorphous region. The polypeptide can be produced using a host that has been transformed by an expression vector containing a gene encoding a polypeptide. A method for producing a gene is not limited particularly, and it may be produced by amplifying a gene encoding a natural spider silk protein from a cell derived from spiders by a polymerase chain reaction (PCR), etc., and cloning it, or may be synthesized chemically. Also, a method for chemically synthesizing a gene is not limited particularly, and it can be synthesized as follows, for example: based on information of amino acid sequences of natural spider silk proteins obtained from the NCBI web database, etc., oligonucleotides that have been synthesized automatically with AKTA oligopilot plus 10/100 (GE Healthcare Japan Corporation) are linked by PCR, etc. At this time, in order to facilitate the purification and observation of protein, it is possible to synthesize a gene that encodes a protein having an amino acid sequence of the above-described amino acid sequence to the N-terminal of which has been added an amino acid sequence composed of a start codon and His 10 tags. Examples of the expression vector include a plasmid, a phage, a virus, and the like that can express protein based on a DNA sequence. The plasmid-type expression vector is not limited particularly as long as it allows a target gene to be expressed in a host cell and it can amplify itself. For example, in the case of using Escherichia coli Rosetta (DE3) as a host, a pET22b(+) plasmid vector, a pCold plasmid vector, and the like can be used. Among these, in terms of productivity of protein, it is preferable to use the pET22b(+) plasmid vector. Examples of the host include animal cells, plant cells, microbes, etc. The polypeptide used in the present disclosure is preferably a polypeptide derived from ADF3, which is one of two principal dragline silk proteins of Araneus diadematus. This polypeptide has advantages of basically having high strength-elongation and toughness and of being synthesized easily. Accordingly, the recombinant silk protein (e.g., the recombinant spider silk-based protein) used in accordance with the embodiments, articles, and/or methods described herein, may include one or more recombinant silk proteins described above or recited in U.S. Patent Nos.8,173,772, 8,278,416, 8,618,255, 8,642,734, 8,691,581, 8,729,235, 9,115,204, 9,157,070, 9,309,299, 9,644,012, 9,708,376, 9,051,453, 9,617,315, 9,968,682, 9,689,089, 9,732,125, 9,856,308, 9,926,348, 10,065,997, 10,316,069, and 10,329,332; and U.S. Patent Publication Nos.2009/0226969, 2011/0281273, 2012/0041177, 2013/0065278, 2013/0115698, 2013/0316376, 2014/0058066, 2014/0079674, 2014/0245923, 2015/0087046, 2015/0119554, 2015/0141618, 2015/0291673, 2015/0291674, 2015/0239587, 2015/0344542, 2015/0361144, 2015/0374833, 2015/0376247, 2016/0024464, 2017/0066804, 2017/0066805, 2015/0293076, 2016/0222174, 2017/0283474, 2017/0088675, 2019/0135880, 2015/0329587, 2019/0040109, 2019/0135881, 2019/0177363, 2019/0225646, 2019/0233481, 2019/0031842, 2018/0355120, 2019/0186050, 2019/0002644, 2020/0031887, 2018/0273590, 20191/094403, 2019/0031843, 2018/0251501, 2017/0066805, 2018/0127553, 2019/0329526, 2020/0031886, 2018/0080147, 2019/0352349, 2020/0043085, 2019/0144819, 2019/0228449, 2019/0340666, 2020/0000091, 2019/0194710, 2019/0151505, 2018/0265555, 2019/0352330, 2019/0248847, and 2019/0378191, the entirety of which are incorporated herein by reference. Silk Fibroin-like Protein Fragments The recombinant silk protein in this disclosure comprises synthetic proteins which are based on repeat units of natural silk proteins. Besides the synthetic repetitive silk protein sequences, these can additionally comprise one or more natural nonrepetitive silk protein sequences. As used herein, “silk fibroin-like protein fragments” refer to protein fragments having a molecular weight and polydispersity as defined herein, and a certain degree of homology to a protein selected from native silk protein, fibroin heavy chain, fibroin light chain, or any protein comprising one or more GAGAGS hexa amino acid repeating units. In some embodiments, a degree of homology is selected from about 99%, about 98%, about 97%, about 96%, about 95%, about 94%, about 93%, about 92%, about 91%, about 90%, about 89%, about 88%, about 87%, about 86%, about 85%, about 84%, about 83%, about 82%, about 81%, about 80%, about 79%, about 78%, about 77%, about 76%, about 75%, or less than 75%. As described herein, a protein such as native silk protein, fibroin heavy chain, fibroin light chain, or any protein comprising one or more GAGAGS hexa amino acid repeating units includes between about 9% and about 45% glycine, or about 9% glycine, or about 10% glycine, about 43% glycine, about 44% glycine, about 45% glycine, or about 46% glycine. As described herein, a protein such as native silk protein, fibroin heavy chain, fibroin light chain, or any protein comprising one or more GAGAGS hexa amino acid repeating units includes between about 13% and about 30% alanine, or about 13% alanine, or about 28% alanine, or about 29% alanine, or about 30% alanine, or about 31% alanine. As described herein, a protein such as native silk protein, fibroin heavy chain, fibroin light chain, or any protein comprising one or more GAGAGS hexa amino acid repeating units includes between 9% and about 12% serine, or about 9% serine, or about 10% serine, or about 11% serine, or about 12% serine. In some embodiments, a silk fibroin-like protein described herein includes about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23 %, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%, about 54%, or about 55% glycine. In some embodiments, a silk fibroin-like protein described herein includes about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, or about 39% alanine. In some embodiments, a silk fibroin-like protein described herein includes about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, or about 22% serine. In some embodiments, a silk fibroin-like protein described herein may include independently any amino acid known to be included in natural fibroin. In some embodiments, a silk fibroin-like protein described herein may exclude independently any amino acid known to be included in natural fibroin. In some embodiments, on average 2 out of 6 amino acids, 3 out of 6 amino acids, or 4 out of 6 amino acids in a silk fibroin-like protein described herein is glycine. In some embodiments, on average 1 out of 6 amino acids, 2 out of 6 amino acids, or 3 out of 6 amino acids in a silk fibroin-like protein described herein is alanine. In some embodiments, on average none out of 6 amino acids, 1 out of 6 amino acids, or 2 out of 6 amino acids in a silk fibroin-like protein described herein is serine. Sericin or Sericin Fragments The main body of the raw silk is silk fibroin fiber, and the silk fibroin fiber is coated with an adhesive substance silk sericin. Sericin is a colloidal silk protein that covers the surface of the silk thread and is composed of bulky amino acids rich in chemical reactivity such as serine, threonine, and aspartic acid, in addition to glycine and alanine. In the various processes of producing silk from raw silk, sericin is important in controlling the solubility of silk and producing high quality silk. Moreover, it plays an extremely important role as an adhesion functional protein. When silk fiber is used as a clothing material, most of the silk sericin covering the silk thread is removed and discarded, so sericin is a valuable unused resource. In some embodiments, the silk protein fragments described herein include sericin or sericin fragments. Methods of preparing sericin or sericin fragments and their applications in various fields are known and are described herein , and are also described, for example, in U.S. Patents Nos.7,115,388, 7,157,273, and 9,187,538, all of which are incorporated by reference herein in their entireties. In some embodiments, sericin removed from the raw silk cocoons, such as in a degumming step, can be collected and used in the methods described herein. Sericin can also be reconstituted from a powder, and used within the compositions and methods of the disclosure. Other Properties of SPF Compositions of the present disclosure are “biocompatible” or otherwise exhibit “biocompatibility” meaning that the compositions are compatible with living tissue or a living system by not being toxic, injurious, or physiologically reactive and not causing immunological rejection or an inflammatory response. Such biocompatibility can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days. In an embodiment, the extended period of time is about 14 days. In an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. For example, in some embodiments, the coatings described herein are biocompatible coatings. In some embodiments, compositions described herein, which may be biocompatible compositions (e.g., biocompatible coatings that include silk), may be evaluated and comply with International Standard ISO 10993-1, titled the “Biological evaluation of medical devices – Part 1: Evaluation and testing within a risk management process.” In some embodiments, compositions described herein, which may be biocompatible compositions, may be evaluated under ISO 106993-1 for one or more of cytotoxicity, sensitization, hemocompatibility, pyrogenicity, implantation, genotoxicity, carcinogenicity, reproductive and developmental toxicity, and degradation. Compositions of the present disclosure are “hypoallergenic” meaning that they are relatively unlikely to cause an allergic reaction. Such hypoallergenicity can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days. In an embodiment, the extended period of time is about 14 days. In an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. In an embodiment, the stability of a composition of the present disclosure is about 1 day. In an embodiment, the stability of a composition of the present disclosure is about 2 days. In an embodiment, the stability of a composition of the present disclosure is about 3 days. In an embodiment, the stability of a composition of the present disclosure is about 4 days. In an embodiment, the stability of a composition of the present disclosure is about 5 days. In an embodiment, the stability of a composition of the present disclosure is about 6 days. In an embodiment, the stability of a composition of the present disclosure is about 7 days. In an embodiment, the stability of a composition of the present disclosure is about 8 days. In an embodiment, the stability of a composition of the present disclosure is about 9 days. In an embodiment, the stability of a composition of the present disclosure is about 10 days. In an embodiment, the stability of a composition of the present disclosure is about 11 days, about 12 days, about 13 days, about 14 days, about 15 days, about 16 days, about 17 days, about 18 days, about 19 days, about 20 days, about 21 days, about 22 days, about 23 days, about 24 days, about 25 days, about 26 days, about 27 days, about 28 days, about 29 days, or about 30 days. In an embodiment, the stability of a composition of the present disclosure is 10 days to 6 months. In an embodiment, the stability of a composition of the present disclosure is 6 months to 12 months. In an embodiment, the stability of a composition of the present disclosure is 12 months to 18 months. In an embodiment, the stability of a composition of the present disclosure is 18 months to 24 months. In an embodiment, the stability of a composition of the present disclosure is 24 months to 30 months. In an embodiment, the stability of a composition of the present disclosure is 30 months to 36 months. In an embodiment, the stability of a composition of the present disclosure is 36 months to 48 months. In an embodiment, the stability of a composition of the present disclosure is 48 months to 60 months. In an embodiment, a SPF composition of the present disclosure is not soluble in an aqueous solution due to the crystallinity of the protein. In an embodiment, a SPF composition of the present disclosure is soluble in an aqueous solution. In an embodiment, the SPF of a composition of the present disclosure include a crystalline portion of about two-thirds and an amorphous region of about one-third. In an embodiment, the SPF of a composition of the present disclosure include a crystalline portion of about one-half and an amorphous region of about one-half. In an embodiment, the SPF of a composition of the present disclosure include between a 99% crystalline portion and a 1% amorphous region, and a 1% crystalline portion and a 99% amorphous region. As used herein, the term “substantially free of inorganic residuals” means that the composition exhibits residuals of 0.1 % (w/w) or less. In an embodiment, substantially free of inorganic residuals refers to a composition that exhibits residuals of 0.05% (w/w) or less. In an embodiment, substantially free of inorganic residuals refers to a composition that exhibits residuals of 0.01 % (w/w) or less. In an embodiment, the amount of inorganic residuals is between 0 ppm (“non-detectable” or “ND”) and 1000 ppm. In an embodiment, the amount of inorganic residuals is ND to about 500 ppm. In an embodiment, the amount of inorganic residuals is ND to about 400 ppm. In an embodiment, the amount of inorganic residuals is ND to about 300 ppm. In an embodiment, the amount of inorganic residuals is ND to about 200 ppm. In an embodiment, the amount of inorganic residuals is ND to about 100 ppm. In an embodiment, the amount of inorganic residuals is between 10 ppm and 1000 ppm. As used herein, the term “substantially free of organic residuals” means that the composition exhibits residuals of 0.1 % (w/w) or less, in an embodiment, substantially free of organic residuals refers to a composition that exhibits residuals of 0.05% (w/w) or less. In an embodiment, substantially free of organic residuals refers to a composition that exhibits residuals of 0.01% (w/w) or less. In an embodiment, the amount of organic residuals is between 0 ppm (“non-detectable” or “ND”) and 1000 ppm. In an embodiment, the amount of organic residuals is ND to about 500 ppm. In an embodiment, the amount of organic residuals is ND to about 400 ppm. In an embodiment, the amount of organic residuals is ND to about 300 ppm. In an embodiment, the amount of organic residuals is ND to about 200 ppm. In an embodiment, the amount of organic residuals is ND to about 100 ppm. In an embodiment, the amount of organic residuals is between 10 ppm and 1000 ppm. Compositions of the present disclosure exhibit “biocompatibility” meaning that the compositions are compatible with living tissue or a living system by not being toxic, injurious, or physiologically reactive and not causing immunological rejection. Such biocompatibility can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days, in an embodiment, the extended period of time is about 14 days, in an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about I month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. Compositions of the present disclosure are “hypoallergenic” meaning that they are relatively unlikely to cause an allergic reaction. Such hypoallergenicity can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days. In an embodiment, the extended period of time is about 14 days. In an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. As used herein, in some embodiments the term “leather” and/or “leather substrate” refers to natural leather and may be derived from bovine skin, sheep skin, lamb skin, horse skin, crocodile skin, alligator skin, avian skin, or another known animal skin as would be appreciated by the art, or processed leather. Unprocessed, processed, coated, and/or repaired leather may include, without limitation, Altered leather, Aniline leather, Bonded leather, Brushed leather, Buffed leather, Bycast leather, Chamois leather, Chrome-tanned leather, Combination tanned leather, Cordovan leather, Corrected grain leather, Crockproof leather, Drummed leather, Embossed leather, Enhanced grain leather, Grained leather, Metallized leather, Naked leather, Natural grain leather, Nubuck leather, Patent leather, Pearlized leather, Plated leather, Printed leather, Protected leather, Pure Aniline leather, Tanned / Retanned leather, Round Hand leather, Saddle leather, Semi-Aniline leather Shrunken grain leather, Side leather, Split leather, Suede leather, and Wet blue. In some embodiments, the term “leather” may refer to synthetic or reconstituted leather, including, but not limited to, leather partially / fully constituted with cellulose, mushroom-based material, synthetic materials such as vinyl, synthetic materials such as polyamide or polyester. As used herein, the term hand refers to the feel of a material, which may be further described as the feeling of softness, crispness, dryness, silkiness, smoothness, and combinations thereof. Material hand is also referred to as “drape.” A material with a hard hand is coarse, rough, and generally less comfortable for the wearer. A material with a soft hand is fluid and smooth and generally more comfortable for the wearer. Material hand can be determined by comparison to collections of material samples, or by use of methods such as the Kawabata Evaluation System (KES) or the Fabric Assurance by Simple Testing (FAST) methods. Behera and Hari, Ind. J. Fibre & Textile Res., 1994, 19, 168-71. In some embodiments, and as described herein, silk can change the hand of leather, as may be evaluated by SynTouch Touch-Scale methodology or another methodology as described herein. As used herein, a “coating” refers to a material, or combination of materials, that form a substantially continuous layer or film on an exterior surface of a substrate, such as leather or leather article. In some embodiments, a portion of the coating may penetrate at least partially into the substrate. In some embodiments, the coating may penetrate at least partially into the interstices of a substrate. In some embodiments, the coating may be infused into a surface of the substrate such that the application of the coating, or coating process, may include infusing (at the melting temperature of the substrate) at least one coating component at least partially into a surface of the substrate. A coating may be applied to a substrate by one or more of the processes described herein. In embodiments described where the coating may be infused into a surface of the substrate, the coating may be codissolved in a surface of the substrate such that a component of the coating may be intermixed in the surface of the substrate to a depth of at least about 1 nm, or at least about 2 nm, or at least about 3 nm, or at least about 4 nm, or at least about 5 nm, or at least about 6 nm, or at least about 7 nm, or at least about 8 nm, or at least about 9 nm, or at least about 10 nm, or at least about 20 nm, or at least about 30 nm, or at least about 40 nm, or at least about 50 nm, or at least about 60 nm, or at least about 70 nm, or at least about 80 nm, or at least about 90 nm, or at least about 100 nm. In some embodiments, the coating may be infused into a surface of the substrate where the substrate includes leather or a leather article. As used herein, the term “bath coating” encompasses coating a material in a bath, immersing a material in a bath, and submerging a material in a bath. Concepts of bath coating are set forth in U.S. Patent No.4,521,458, the entirety of which is incorporated by reference. As used herein, and unless more specifically described, the term drying may refer to drying a coated material as described herein at a temperature greater than room temperature (i.e., 20 °C). Without wishing to be bound by any particular theory, any and all solutions described herein can be further used or processed to obtain a variety of silk and/or SPF compositions, including, but not limited to, silk non-Newtonian fluids, silk materials that can sustain a shear stress network spanning the system, silk solutions containing water or another solvent trapped inside a loose silk polymer network, silk materials that transition from a liquid form via bond percolation transition such as gels, silk immobile network entrapping a mobile solvent, silk materials forming reversible or irreversible crosslinks, silk materials that exhibit a shear modulus, silk elastomers or silk materials exhibiting thermoplastic behavior, silk materials formed by the processes of either glass formation, gelation, or colloidal aggregation, silk crystals, and/or silk crystals polish, glues, gels, pastes, putties, and/or waxes. As used herein when referring to a number or a numerical range, the term “about” means that the stated number or numerical range is included together with numbers or numerical ranges within experimental variability, or within statistical experimental error from the stated number or numerical range, wherein the variation or error is from 0% to 15%, or from 0% to 10%, or from 0% to 5% of the stated number or numerical range. As used herein, “silk based proteins or fragments thereof” includes silk fibroin-based proteins or fragments thereof, natural silk based proteins or fragments thereof, recombinant silk based proteins or fragments thereof, and combinations thereof. Natural silk based proteins or fragments thereof include spider silk based proteins or fragments thereof, silkworm silk based proteins or fragments thereof, and combinations thereof. Silkworm based proteins or fragments thereof may include Bombyx mori silk based proteins or fragments thereof. The SPF mixture solutions described herein may include silk based proteins or fragments thereof. Moreover, SFS, as described herein, may be replaced with SPF mixture solutions. The silk based proteins or fragments thereof, silk solutions or mixtures (e.g., SPF or SFS solutions or mixture), and the like, may be prepared according to the methods described in U.S. Patent Nos.9,187,538, 9,522,107, 9,522,108, 9,511, 012, 9,517,191, and 9,545,369, and U.S. Patent Publication Nos.2016/0222579 and 2016/0281294, and International Patent Publication Nos. WO 2016/090055 and WO 2017/011679, the entirety of which are incorporated herein by reference. In some embodiments, the silk based proteins or fragments thereof may be provided as a silk composition, which may be an aqueous solution or mixture of silk, a silk gel, and/or a silk wax as described herein. As used herein, the terms substantially sericin free or substantially devoid of sericin” refer to silk fibers in which a majority of the sericin protein has been removed. In an embodiment, silk fibroin that is substantially devoid of sericin refers to silk fibroin having between about 0.01% (w/w) and about 10.0% (w/w) sericin. In an embodiment, silk fibroin that is substantially devoid of sericin refers to silk fibroin having a sericin content below about 0.05 % (w/w). In an embodiment, when a silk source is added to a boiling (100 °C) aqueous solution of sodium carbonate for a treatment time of between about 30 minutes to about 60 minutes, a degumming loss of about 26 wt. % to about 31 wt.% is obtained. As used herein, the term “substantially homogeneous” may refer to pure silk fibroin- based protein fragments that are distributed in a normal distribution about an identified molecular weight. As used herein, the term “substantially homogeneous” may refer to an even distribution of an additive, for example a pigment, throughout a composition of the present disclosure. As used herein, “residuals” refer to materials related to one or more process steps in the manufacturing of silk fibroin solutions, silk fibroin fragments solutions, or concentrates thereof. In some embodiments, compositions of the present disclosure are “biocompatible” or otherwise exhibit “biocompatibility” meaning that the compositions are compatible with living tissue or a living system by not being toxic, injurious, or physiologically reactive and not causing immunological rejection or an inflammatory response. Such biocompatibility can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days. In an embodiment, the extended period of time is about 14 days. In an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. For example, in some embodiments, the coatings described herein are biocompatible coatings. In some embodiments, compositions described herein, which in some embodiments may be biocompatible compositions (e.g., biocompatible coatings that include silk), may be evaluated and comply with International Standard ISO 10993-1, titled the “Biological evaluation of medical devices – Part 1: Evaluation and testing within a risk management process. In some embodiments, compositions described herein, which may be biocompatible compositions, may be evaluated under ISO 106993-1 for one or more of cytotoxicity, sensitization, hemocompatibility, pyrogenicity, implantation, genotoxicity, carcinogenicity, reproductive and developmental toxicity, and degradation. In some embodiments, compositions and articles described herein, and methods of preparing the same, include silk coated leather or leather article. The leather or leather article may be a polymeric material such as those described elsewhere herein. The terms “infused” and/or “partially dissolved” includes mixing to form a dispersion of, e.g., a portion of leather or leather article with a portion of the silk based coating. In some embodiments, the dispersion may be a solid suspension (i.e., a dispersion comprising domains on the order of 10 nm) or a solid solution (i.e., a molecular dispersion) of silk. In some embodiments, the dispersion may be localized at the surface interface between the silk coating and the leather or leather article, and may have a depth of 1 nm, 2 nm, 5 nm, 10 nm, 25 nm, 50 nm, 75 nm, 100 nm, or greater than 100 nm, depending on the method of preparation. In some embodiments, the dispersion may be a layer sandwiched between the leather or leather article and the silk coating. In some embodiments, the dispersion may be prepared by coating silk, including silk fibroin with the characteristics described herein, onto the leather or leather article, and then performing an additional process to form the dispersion, including heating at a temperature of 100 °C, 125 °C, 150 °C, 175 °C, 200 °C, 225 °C, or 250 °C for a time period selected from the group consisting of 1 minute, 2 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, or 24 hours. In some embodiments, heating may be performed at or above the glass transition temperature (Tg) of silk and/or the polymeric fabric or textile, which may be assessed by methods known in the art. In some embodiments, the dispersion may be formed by coating silk, including silk fibroin with the characteristics described herein, onto the leather or leather article, and then performing an additional process to impregnate the silk coating into the leather or leather article, including treatment with an organic solvent. Methods for characterizing the properties of polymers dissolved in one another are well known in the art and include differential scanning calorimetry and surface analysis methods capable of depth profiling, including spectroscopic methods. In some embodiments, compositions of the present disclosure are “hypoallergenic” meaning that they are relatively unlikely to cause an allergic reaction. Such hypoallergenicity can be evidenced by participants topically applying compositions of the present disclosure on their skin for an extended period of time. In an embodiment, the extended period of time is about 3 days. In an embodiment, the extended period of time is about 7 days. In an embodiment, the extended period of time is about 14 days. In an embodiment, the extended period of time is about 21 days. In an embodiment, the extended period of time is about 30 days. In an embodiment, the extended period of time is selected from the group consisting of about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 7 months, about 8 months, about 9 months, about 10 months, about 11 months, about 12 months, and indefinitely. In some embodiments, where aqueous solutions are used to prepare SPF compositions or SPF containing coatings, the aqueous solutions are prepared using any type of water. In some embodiments, water may be DI water, tap water, or naturally available water. As used herein, “tap water” refers to potable water provided by public utilities and water of comparable quality, regardless of the source, without further refinement such as by reverse osmosis, distillation, and/or deionization. Therefore, the use of “DI water,” “RODI water,” or “water,” as set forth herein, may be understood to be interchangeable with “tap water” according to the processes described herein without deleterious effects to such processes. Leather and Leather Articles Processed, Coated, and/or Repaired with Silk Fibroin-Based Protein Fragments In one aspect, the present disclosure provides a coating composition comprising silk fibroin proteins or fragments thereof. In an embodiment, the silk fibroin proteins or fragments thereof have an average weight average molecular weight in a range selected from between about 1 kDa and about 5 kDa, between about 5 kDa and about 10 kDa, between about 6 kDa and about 17 kDa, between about 10 kDa and about 15 kDa, between about 14 kDa and about 30 kDa, between about 15 kDa and about 20 kDa, between about 17 kDa and about 39 kDa, between about 20 kDa and about 25 kDa, between about 25 kDa and about 30 kDa, between about 30 kDa and about 35 kDa, between about 35 kDa and about 40 kDa, between about 39 kDa and about 80 kDa, between about 40 kDa and about 45 kDa, between about 45 kDa and about 50 kDa, between about 60 kDa and about 100 kDa, and between about 80 kDa and about 144 kDa, and a polydispersity between 1 and about 5. In some embodiments, the silk fibroin proteins or fragments thereof have any average weight average molecular weight described herein. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between 1 and about 1.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 1.5 and about 2. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 2 and about 2.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 2.5 and about 3. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 3 and about 3.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 3.5 and about 4. In some embodiments, of claim 1, wherein the silk fibroin proteins or fragments thereof have a polydispersity between about 4 and about 4.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 4.5 and about 5. In an embodiment, the silk fibroin proteins or fragments thereof have any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, and about 0.001% (w/w) to about 10% (w/w) sericin relative to the silk fibroin proteins or fragments thereof. In some embodiments, the w/w ratio between silk fibroin proteins or fragments thereof and sericin is about 99:1, about 98:2, about 97:3, about 96:4, about 95:5, about 94:6, about 93:7, about 92:8, about 91:9, about 90:10, about 89:11, about 88:12, about 87:13, about 86:14, about 85:15, about 84:16, about 83:17, about 82:18, about 81:19, about 80:20, about 79:21, about 78:22, about 77:23, about 76:24, or about 75:25. In some embodiments, the relative w/w amount of sericin to the silk fibroin proteins or fragments thereof is about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, 0.4%, about 0.3%, about 0.2%, about 0.1%, about 0.01%, or about 0.001%. In an embodiment, the silk fibroin proteins or fragments thereof have any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, wherein the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in an aqueous solution for at least 10 days prior to being coated onto the article. In some embodiments, the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in an aqueous solution for at least 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 4 weeks, or 1 month prior to being coated on the article. In one aspect, the present disclosure provides an article coated with the coating composition described elsewhere herein. In an embodiment, the article is a leather article such as a leather substrate. Some methods for adding a protein to a substrate, including a leather substrate, are described in U.S. Pat. No.8,993,065, incorporated herein by reference in its entirety. The disclosure also provides an article including a leather substrate and silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, wherein: 1) a portion of the silk fibroin proteins or fragments thereof is coated on a surface of the leather substrate; or 2) a portion of the silk fibroin proteins or fragments thereof is infused into a layer of the leather substrate, in some embodiments, such layers having a thickness as described herein; or 3) a portion of the silk fibroin proteins or fragments thereof is in a recessed portion of the leather substrate selected from an opening, a crevice, and a defect in the leather substrate; or 4) any combination of the above. Referring to FIGS.22A and 22B, the manner in which a portion of the silk fibroin proteins or fragments thereof is coated on a surface of the leather substrate, or the manner in which a portion of the silk fibroin proteins or fragments thereof is in a recessed portion of the leather substrate, can be described by way of a cross-section index, wherein a cross-section index is defined as the ratio between the area above the curve up to a baseline and the length of the cross section across which the area above the curve is determined. The cross-section index is reflected herein as a unitless value. The curve may reflect the leather surface (if uncoated or unfilled) along a cross-section, or a surface of a silk fibroin proteins or fragments thereof coating or filling along a cross-section. The baseline may reflect a horizontal plane approximating the surface of the leather substrate across the segment through which the cross-section index is determined. As shown in FIG.49A, a recessed portion is for example between the cross-section x1 = about 210 µm, and x2 = about 600 µm, and the cross-section index of this recessed portion can be calculated as described herein. In some embodiments, a recessed portion of the leather substrate has a cross-section index of about 6.50, about 6.75, about 7, about 7.25, about 7.50, about 7.75, about 8, about 8.25, about 8.50, about 8.75, about 9, about 9.25, about 9.50, about 9.75, or about 10. In some embodiments, a recessed portion of the leather substrate can have another cross-section index, for example about 5, about 5.1, about 5.2, about 5.3, about 5.4, about 5.5, about 5.6, about 5.7, about 5.8, about 5.9, about 6, about 6.1, about 6.2, bout 6.3, about 6.4, about 6.5, about 6.6, about 6.7, about 6.8, about 6.9, about 7, about 7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7, about 7.8, about 7.9, about 8, about 8.1, about 8.2, bout 8.3, about 8.4, about 8.5, about 8.6, about 8.7, about 8.8, about 8.9, about 9, about 9.1, about 9.2, about 9.3, about 9.4, about 9.5, about 9.6, about 9.7, about 9.8, about 9.9, or about 10. Also as shown in FIG.49A, a substantially non-recessed portion of the leather substrate is for example between the cross-section x1 = 0 µm, and x2 = about 210 µm, and the cross-section index of this substantially non-recessed portion can be calculated as described herein. In some embodiments, a substantially non-recessed portion of the leather substrate has a cross-section index of about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, or about 2.0. In some embodiments, a substantially non-recessed portion of the leather substrate can have another cross-section index, for example about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 1.1, about 1.2, bout 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8, about 2.9, or about 3. As shown in FIG.22B, a recessed portion filled with silk fibroin proteins or fragments thereof is for example between the cross-section x1 = about 210 µm, and x2 = about 395 µm, and the cross-section index of this filled recessed portion can be calculated as described herein. In some embodiments, a filled recessed portion of the leather substrate can have a cross-section index of about 0.25, about 0.50, about 0.75, about 1, about 1.25, about 1.27, about 1.50, about 1.75, or about 2. In some embodiments, a filled recessed portion of the leather substrate can have any other cross-section index, for example about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 1.1, about 1.2, bout 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8, about 2.9, or about 3. Also as shown in FIG.22B, a substantially non-recessed portion of the leather substrate coated with silk fibroin proteins or fragments thereof is for example between the cross-section x1 = 0 µm, and x2 = about 210 µm, and the cross-section index of this recessed portion can be calculated as described herein. In some embodiments, a coated substantially non-recessed portion of the leather substrate has a cross-section index of about 0.05, about 0.1, about 0.15, about 0.2, about 0.25, about 0.50, about 0.75, about 1, about 1.25, about 1.27, about 1.50, about 1.75, or about 2. In some embodiments, a coated substantially non-recessed portion of the leather substrate can have any other cross-section index, for example about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 1.1, about 1.2, bout 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8, about 2.9, or about 3. In some embodiments, a coated substantially non-recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating. In some embodiments, a coated substantially non- recessed portion of the leather substrate has a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating, wherein the cross-section index of the coated substantially non-recessed portion of the leather substrate is higher than 0. In some embodiments, a coated substantially non-recessed portion of the leather substrate has a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating by a factor between 1% and 99%. In some embodiments, a coated substantially non-recessed portion of the leather substrate may have a cross-section index lower than a substantially recessed portion of the leather substrate before filling. In some embodiments, a coated substantially non-recessed portion of the leather substrate has a cross-section index lower than a substantially recessed portion of the leather substrate before filling, wherein the cross-section index of the coated substantially non-recessed portion of the leather substrate is higher than 0. In some embodiments, a coated substantially non-recessed portion of the leather substrate has a cross- section index lower than a substantially recessed portion of the leather substrate before filling by a factor between 1% and 99%. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating, wherein the cross-section index of the filled recessed portion of the leather substrate is higher than 0. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before coating by a factor between 1% and 99%. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before filling. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before filling, wherein the cross-section index of the filled recessed portion of the leather substrate is higher than 0. In some embodiments, a filled recessed portion of the leather substrate may have a cross-section index lower than a substantially non-recessed portion of the leather substrate before filling by a factor between 1% and 99%. The disclosure also provides an article including a leather substrate and silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, the article further including one or more polysaccharides selected from starch, cellulose, gum arabic, guar gum, xanthan gum, alginate, pectin, chitin, chitosan, carrageenan, inulin, and gellan gum. In some embodiments, the polysaccharide is gellan gum. In some embodiments, the gellan gum comprises low-acyl content gellan gum. The disclosure also provides an article including a leather substrate and silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, the article further including one or more polyols, and/or one or more polyethers. In some embodiments, the polyols include one or more of glycol, glycerol, sorbitol, glucose, sucrose, and dextrose. The disclosure also provides an article including a leather substrate and silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other limitations described herein, the article further including one or more of a silicone, a dye, a pigment, and a polyurethane as described herein. In an embodiment, an aqueous coating composition described elsewhere herein is applied directly to the article. In an embodiment, a silk coating described elsewhere herein can be coated on the article to form a pattern or design on the article. In an embodiment, a coating composition described elsewhere herein is applied to a leather or leather article under tension and/or lax to vary penetration into the leather or leather article. In an embodiment, the disclosure provides leather and leather articles coated with a silk composition described herein. In an embodiment, the disclosure provides leather and leather articles repaired with a silk composition described herein, for example by filling, masking, or hiding a defect in the surface or structure of the leather. In an embodiment, the disclosure provides leather and leather articles processed with any one of herein described silk compositions and a dye to provide colored leather and leather articles exhibiting enhanced color-saturation and excellent color-fixation properties. In some embodiments, the silk composition may be applied currently with the dye. In some embodiments, the silk composition may be applied prior to the dyeing process. In some embodiments, the silk composition may be applied post the dyeing process. In some embodiments, the leather may include nubuck skin in crust, nubuck skin finished in black or blue color, suede skin fined in brown or turquoise color, bottom split suede, or top split wet blue suede. The disclosure provides generally to methods and articles related to filling a recessed portion of a leather, such as, without limitation, an opening, a crevice, or a defect in a leather substrate, with silk fibroin proteins and/or fragments thereof. As used herein, the term “defect” or “leather defect,” refers to any imperfection in or on the surface, and/or the underlying structure of the leather. For example, removal of a hair and/or hair follicle may leave a visible void or gap in the surface or structure of the leather or hide. This disclosure is not limited to repairing visible defects, and thus it is contemplated that any defects can be repaired as described herein. This disclosure is likewise not limited to repairing defects of a certain size, and defects of any size can be repaired and/or filled. For example, silk and/or SPFs, and any and all compositions described herein, can be used to fill in or mask the appearance of larger defects occurring over larger areas of a defective skin surface. As used herein, “repaired” or “repairing” leather refers to filling a defect with a composition including silk and/or SPF, wherein as a result of such repairing the defect is substantially eliminated. For example, a void or gap which is fully or partially filled with a composition as described herein may be a repaired defect. In an embodiment, the disclosure provides a leather or leather article processed, coated, and/or repaired with silk fibroin-based proteins or fragments thereof. In an embodiment, the disclosure provides a leather or leather article processed, coated, or repaired with silk fibroin-based proteins or fragments thereof, wherein the leather or leather article is a leather or leather article used for human apparel, including apparel. In an embodiment, the disclosure provides a leather or leather article processed, coated, or repaired with silk fibroin- based proteins or fragments thereof, wherein the leather or leather article is used for automobile upholstery. In an embodiment, the disclosure provides a leather or leather article processed, coated, or repaired with silk fibroin-based proteins or fragments thereof, wherein the leather or leather article is used for aircraft upholstery. In an embodiment, the disclosure provides a leather or leather article processed, coated, or repaired with silk fibroin-based proteins or fragments thereof, wherein the leather or leather article is used for upholstery in transportation vehicles for public, commercial, military, or other use, including buses and trains. In an embodiment, the disclosure provides a leather or leather article processed, coated, or repaired with silk fibroin-based proteins or fragments thereof, wherein the leather or leather article is used for upholstery of a product that requires a high degree of resistance to wear as compared to normal upholstery. In an embodiment, a leather or leather article is treated with a polymer, such as polyglycolide (PGA), polyethylene glycols, copolymers of glycolide, glycolide/L-lactide copolymers (PGA/PLLA), glycolide/trimethylene carbonate copolymers (PGA/TMC), polylactides (PLA), stereocopolymers of PLA, poly-L-lactide (PLLA), poly-DL-lactide (PDLLA), L-lactide/DL-lactide copolymers, co-polymers of PLA, lactide/tetramethylglycolide copolymers, lactide/trimethylene carbonate copolymers, lactide/δ-valerolactone copolymers, lactide/ε-caprolactone copolymers, polydepsipeptides, PLA/polyethylene oxide copolymers, unsymmetrically 3,6-substituted poly-1,4-dioxane-2,5- diones, poly-β-hydroxybutyrate (PHBA), PHBA/β-hydroxyvalerate copolymers (PHBA/HVA), poly-β-hydroxypropionate (PHPA), poly-p-dioxanone (PDS), poly-δ- valerolactone, poly-ε-caprolactone, methylmethacrylate-N-vinyl pyrrolidine copolymers, polyesteramides, polyesters of oxalic acid, polydihydropyrans, polyalkyl-2-cyanoacrylates, polyurethanes (PU), polyvinylalcohols (PVA), polypeptides, poly-β-malic acid (PMLA), poly-β-alkanoic acids, polyvinylalcohol (PVA), polyethyleneoxide (PEO), chitine polymers, polyethylene, polypropylene, polyasetal, polyamides, polyesters, polysulphone, polyether ether ketone, polyethylene terephthalate, polycarbonate, polyaryl ether ketone, and polyether ketone ketone. In an embodiment, an aqueous solution of pure silk fibroin-based protein fragments of the present disclosure is used to process and/or coat a leather or leather article. In an embodiment, the concentration of silk in the solution ranges from about 0.1% to about 20.0%. In an embodiment, the concentration of silk in the solution ranges from about 0.1% to about 15.0%. In an embodiment, the concentration of silk in the solution ranges from about 0.5% to about 10.0%. In an embodiment, the concentration of silk in the solution ranges from about 1.0% to about 5.0%. In an embodiment, an aqueous solution of pure silk fibroin-based protein fragments of the present disclosure is applied directly to a leather or leather article. Alternatively, silk microsphere and any additives may be used for processing and/or coating a leather or leather article. In an embodiment, additives can be added to an aqueous solution of pure silk fibroin-based protein fragments of the present disclosure before coating (e.g., alcohols) to further enhance material properties. In an embodiment, a silk coating of the present disclosure can have In an embodiment, a composition of pure silk fibroin-based protein fragments of the present disclosure is used to repair a leather or leather article. In some embodiments, the composition is viscous. In some embodiments, the composition is thixotropic. In some embodiments, the composition is a gel, a putty, a wax, a paste, or the like. In some embodiments, the composition is shaped as a repairing bar, for example a repairing crayon. In some embodiments, the composition is delivered from a syringe, a delivery gun, a brush-type applicator, a roller-type applicator, a pen or marker-type applicator, or the like. In some embodiments, the composition is co-delivered from a multiple syringe, for example a double syringe, or a double delivery gun, along a different composition designed to harden, initiate curing of, or otherwise modify the SPF composition. In an embodiment, the concentration of silk in the composition ranges from about 0.1% to about 50.0%. In an embodiment, the concentration of silk in the solution ranges from about 0.1% to about 35.0%. In an embodiment, the concentration of silk in the solution ranges from about 0.5% to about 30.0%. In an embodiment, the concentration of silk in the solution ranges from about 1.0% to about 25.0%. In an embodiment, a composition of pure silk fibroin-based protein fragments of the present disclosure is applied directly to a leather or leather article, for example to a leather defect. Alternatively, silk microsphere and any additives may be used for repairing a leather or leather article. In an embodiment, additives can be added to the composition of pure silk fibroin-based protein fragments of the present disclosure before coating (e.g., alcohols) to further enhance material properties. In an embodiment, a composition is applied to a leather or leather article under tension and/or lax to vary penetration in to the leather, leather article, or leather defect. In an embodiment, the disclosure provides a leather or leather article coated with the coating composition describe elsewhere herein. In an embodiment, the leather or leather article is an aniline leather or leather article. In an embodiment, the leather or leather article is used for human apparel, automobile upholstery, aircraft upholstery, or upholstery in transportation vehicles for public, commercial, military, or other use, including buses and trains. In an embodiment, the disclosure provides a leather or leather article coated with the mattifying coating composition described elsewhere herein, wherein the leather or leather article is used for a product wherein a matte effect is desired. In another embodiment, the disclosure provides an aniline leather or aniline leather article coated with the water soluble dye fixing coating composition described elsewhere herein. In an embodiment, the aniline leather or aniline leather article is coated with a water soluble dye fixing coating composition described herein comprising a water soluble aniline leather dye. In an embodiment, the water soluble dye fixing coating composition described herein comprising a water soluble aniline leather dye fixes the aniline leather dye during aniline leather finishing, providing a dyed leather with a natural look and/or feel. In an embodiment, the concentration of the water soluble dye and/or water soluble aniline leather dye can be tuned to provide a deeper color of the dyed leather or a lighter color of the dyed leather. Methods of Coating an Article with the Coating Composition In yet another aspect, the present disclosure provides a method of coating an article with a coating composition, the method comprising applying the coating composition to one or more surfaces of the article. The coating composition is described elsewhere herein. In an embodiment, the coating composition comprises silk fibroin proteins or fragments thereof and a mattifying silica and/or starch. In another embodiment, the coating composition comprises silk fibroin proteins or fragments thereof and a water soluble dye. In another embodiment, the coating composition is a two part coating composition wherein the first part comprises a water soluble dye and the second part comprises silk fibroin proteins or fragments thereof. In an embodiment, the coating composition is a liquid, a gel, a paste, a wax, or a cream. In an embodiment, the coating composition is a liquid. In one embodiment, the coating composition comprises an aqueous solvent. In one embodiment wherein the coating composition is a liquid, the method further comprises the step of drying the article. The coating composition described herein may be applied to the article using any method known to a person of skill in the art. Exemplary application methods include, but are not limited to, hand-spraying, spraying using a mechanical spray setup, applying by brush, rubbing, wet-mixing, washing, drumming, soaking, injecting, plastering, smearing, or the like. In an embodiment wherein the coating composition comprises silk fibroin proteins or fragments thereof and a water soluble dye, the coating composition is sprayed onto the article in one application of about 4 g/sqft. In an embodiment, the coating composition comprising silk fibroin proteins or fragments thereof and a water soluble dye is sprayed onto a leather article in one application of about 4 g/sqft. In some embodiments, a coating composition described herein may be applied to an article alone, mixed with one or several chemicals (e.g., chemical agents), as one coat, multiple coats, or at multiple times using varied application methods. In an embodiment, the thickness of the coating is described elsewhere herein. In embodiments wherein the coating composition is a two part coating composition, the step of applying the coating composition to one or more surfaces of the article comprises (a) applying the first part of the coating composition to one or more surfaces of the article. In an embodiment, a first part of the coating composition comprising a water soluble dye is applied to one or more surfaces of the article. In an embodiment, a first part of the coating composition comprising a water soluble dye is applied to one or more surfaces of a leather article. In an embodiment, the first part of the coating composition is applied to the leather article by spraying. In an embodiment, the first part of the coating composition is applied to the leather article by spraying a first layer at about 2 g/sqft onto the article. In an embodiment, the method further comprises the step (b) of drying the leather article after the first layer of the first part of the coating composition is applied. In an embodiment, the method further comprises (c) applying a second layer of the first part of the coating composition to one or more surfaces of the dried leather article. In an embodiment, the first part of the coating composition is applied to the dried leather article by spraying. In an embodiment, the first part of the coating composition is applied to the dried leather article by spraying a second layer at about 2 g/sqft onto the article. In some embodiments, the method further comprises (d) drying the leather article after the second layer of the first part of the coating composition is applied to the article. In an embodiment, the method further comprises (e) applying the second part of the coating composition to one or more surfaces of the article. In an embodiment, a second part of the coating composition comprising silk fibroin proteins or fragments thereof is applied to one or more surfaces of the article. In an embodiment, a second part of the coating composition comprising silk fibroin proteins or fragments thereof is applied to one or more surfaces of a leather article. In an embodiment, the second part of the coating composition is applied to the leather article by spraying. In an embodiment, the second part of the coating composition is applied to the leather article by spraying a layer of the second part of the coating composition at about 4 g/sqft onto the article. In an embodiment, only one layer of the second part of the coating composition is applied to the leather article. In an embodiment, the method further comprises (f) drying the leather article after the second part of the coating composition is applied to the article. In an embodiment, the coating composition comprising silk fibroin proteins or fragments thereof and a water soluble dye as a one part coating composition has a comparable performance to the two part coating composition when applied as a coating on an article. In an embodiment, the one part coating composition has a similar ability to maintain colorfastness to rubbing as the two part coating composition. Paper Transfer Process In some embodiments, a layer or coating described herein can be applied by paper transfer or paper release process. See for example Figure 129 and Figure 130. Description of a paper release process can also be found in Internation Publication No. WO2020209717, which is incorporated by reference herein. The paper release process may be useful for imprinting a grain pattern on a substrate (ex. Leather), maintaining texture integrity, imparting patterns, or textile nobilitation. Coating with Topographical Features Embodiments of the present disclosure provide an article comprising a substrate and a coating, wherein the coating comprises a base layer comprising a first polymeric macromolecular species or polymer and a top layer comprising a second polymeric macromolecular species or polymer, wherein the base layer comprises mechanically engineered topographical features on a surface opposite to the substrate, wherein the engineered topographical features have width and/or depth dimensions on a scale of from about 0 µm to about 250 µm, wherein a portion of the base layer and a portion of the top layer form a composite layer which substantially represents and/or retains the topographical features of the base layer. In some embodiments, the engineered topographical features have width and/or depth dimensions on a scale of from about 0 µm to about 50 µm, from about 50 µm to about 100 µm, from about 100 µm to about 150 µm, from about 150 µm to about 200 µm, or from about 200 µm to about 250 µm. In some embodiments, the article further comprises one or more additional layers disposed between the substrate and the base layer, the additional layers selected from a preground layer, a ground layer, and an adhesive layer. In some embodiments, the base layer topographical features are substantially different from any non-engineered topographical features of the substrate, the preground layer, the ground layer, and/or the adhesive layer. In some embodiments, the composite layer topographical features are substantially different from any non-engineered topographical features of the substrate, the preground layer, the ground layer, and/or the adhesive layer. In some embodiments, the composite layer comprises a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer. In some embodiments, the mechanically engineered topographical features comprise one or more of mechanically engineered embossed features, mechanically engineered relieved features, mechanically engineered recessed features, mechanically engineered imprinted features, and/or mechanically engineered repetitive features. In some embodiments, the mechanically engineered topographical features comprise one or more of mechanically engineered imprinted features and/or mechanically engineered imparted patterns. In some embodiments, the mechanically engineered topographical features comprise one or more of mechanically engineered imprinted grain patterns. In some embodiments, the mechanically engineered topographical features comprise one or more mechanically engineered imprinted fine grain features having a grain depth between 0 μm to 100 μm. In some embodiments, the mechanically engineered topographical features comprise one or more mechanically engineered imprinted fine grain features having a grain depth of between about 0 μm to about 10 μm, between about 10 μm to about 20 μm, between about 20 μm to about 30 μm, between about 30 μm to about 40 μm, between about 40 μm to about 50 μm, between about 50 μm to about 60 μm, between about 60 μm to about 70 μm, between about 70 μm to about 80 μm, between about 80 μm to about 90 μm, between about 90 μm to about 100 μm, between about 100 μm to about 110 μm, between about 110 μm to about 120 μm, between about 120 μm to about 130 μm, between about 130 μm to about 140 μm, or between about 140 μm to about 150 μm. In some embodiments, the mechanically engineered topographical features comprise one or more mechanically engineered imprinted coarse grain features having a grain depth between 100 μm to 150 μm, or between 150 μm to 500 μm. In some embodiments, the mechanically engineered topographical features comprise one or more mechanically engineered imprinted coarse grain features having a grain depth of between about 100 μm to about 110 μm, between about 110 μm to about 120 μm, between about 120 μm to about 130 μm, between about 130 μm to about 140 μm, between about 140 μm to about 150 μm, between about 150 μm to about 160 μm, between about 160 μm to about 170 μm, between about 170 μm to about 180 μm, between about 180 μm to about 190 μm, or between about 190 μm to about 200 μm. In some embodiments, the composite layer comprises a portion of the base layer and a portion of the top layer which are physically and/or chemically entangled, and/or physically and/or chemically crosslinked, and/or chemically and/or physically integrated. In some embodiments, the adhesive layer comprises and/or is generated by one or more of an acrylic dispersion, a polyurethane dispersion, a waterborne urethane-acrylic hybrid dispersion (HPDS), a wax, an oil in water emulsion, and/or a polysiloxane. In some embodiments, the first polymeric macromolecular species or polymer comprises a protein component. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the base layer comprises and/or is generated by one or more of a polyurethane dispersion, a wax, an oil in water emulsion, and/or a protein binder. In some embodiments, the first polymeric macromolecular species or polymer comprises a poly lactic acid (PLA) component, and/or a poly(lactic-co-glycolic acid) (PLGA) component. In some embodiments, the first polymeric macromolecular species or polymer comprises a biodegradable polymer. In some embodiments, the base layer has a thickness between about 10 µm and about 35 µm. In some embodiments, the base layer has a thickness between about 35 µm and about 100 µm. In some embodiments, the base layer has a thickness between about 100 µm and about 250 µm. In some embodiments, the base layer has a thickness between about 5 µm and 15 µm, between about 15 µm and 20 µm, between about 20 µm and 25 µm, between about 25 µm and 35 µm, between about 30 µm and 35 µm, or between about 35 µm and 40 µm. In some embodiments, the base layer has a thickness of about 10 µm, about 15 µm, about 20 µm, about 25 µm, about 30 µm, or about 35 µm. In some embodiments, the second polymeric macromolecular species or polymer comprises one or more of a cellulose derivative, an aliphatic or aromatic polyurethane, a silanol/amino-polysiloxane emulsions, a crosslinked PU, treated silicas, and/or a protein component. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, the second polymeric macromolecular species or polymer comprises a biodegradable polymer. In some embodiments, the second polymeric macromolecular species or polymer comprises a cellulose and/or cellulose derivative component. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%, of between about 5% and less than about 100%, of between about 10% and about 20%, between about 20% and about 30%, between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%, less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%, less than about 84%, less than about 83%, less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%, less than about 71%, less than about 70%, less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%, less than about 32%, less than about 31%, less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%. In some embodiments, the top layer has a thickness between about 5 µm and about 10 µm. In some embodiments, the top layer has a thickness between about 1 µm and about 10 µm. In some embodiments, the top layer has a thickness between about 10 µm and about 25 µm. In some embodiments, the top layer has a thickness between about 25 µm and about 50 µm. In some embodiments, the top layer has a thickness between about 5 µm and about 6 µm, between about 6 µm and about 7 µm, between about 7 µm and about 8 µm, between about 8 µm and about 9 µm, or between about 9 µm and about 10 µm. In some embodiments, the top layer has a thickness of about 5 µm, about 6 µm, about 7 µm, about 8 µm, aboubt 9 µm, or about 10 µm. In some embodiments, the thickness ratio between the base layer and the top layer ranges from about 10:1 to about 1:1. In some embodiments, the thickness ratio between the base layer and the top layer is about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, or about 1:1. In some embodiments, the thickness ratio between the base layer and the top layer is between about 10:1 and about 9:1, between about 9:1 and about 8:1, between about 8:1 and about 7:1, between about 7:1 and about 6:1, between about 6:1 and about 5:1, between about 5:1 and about 4:1, between about 4:1 and about 3:1, between about 3:1 and about 2:1, or between about 2:1 and about 1:1. In some embodiments, the top layer does not include an adhesive material or cross- linker. In some embodiments, the first polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite layer. In some embodiments, the second polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite layer. In some embodiments, the substrate comprises an irregular surface. In some embodiments, the substrate comprises topographical features which are not mechanically engineered. In some embodiments, the coating has a thickness between about 10 µm and about 1000 µm. In some embodiments, the coating has a thickness between about 10 µm and about 100 µm, between about 100 µm and about 200 µm, between about 200 µm and about 300 µm, between about 300 µm and about 400 µm, between about 400 µm and about 500 µm, between about 500 µm and about 600 µm, between about 600 µm and about 700 µm, between about 700 µm and about 800 µm, between about 800 µm and about 900 µm, or between about 900 µm and about 1000 µm. In some embodiments, the amount of coating on the substrate is between about 0.01 g/ft² and about 25 g/ft². In some embodiments, the amount of coating on the substrate is between about 0 g/ft² and about 5 g/ft², between about 5 g/ft² and about 10 g/ft², between about 10 g/ft² and about 15 g/ft², between about 15 g/ft² and about 20 g/ft², between about 20 g/ft² and about 25 g/ft², between about 25 g/ft² and about 30 g/ft², between about 30 g/ft² and about 35 g/ft²m, or between about 30 g/ft² and about 40 g/ft², In some embodiments, the substrate comprises a substantially flexible material. In some embodiments, the substrate comprises a leather material or a textile material. In some embodiments, the substrate comprises one or more of collagen, fibroin, keratin, cellulose, and/or lignin. In some embodiments, the coating comprises one or more mattifying agent. In some embodiments, the coating comprises one or more plasticizer. In some embodiments, the coating comprises a plurality of modified fibroin fragments, each comprising one or more amino acid residue modifications selected from an asparagine to aspartic acid modification, a glutamine to glutamic acid modification, and a methionine to methionine oxide modification. In some embodiments, a plurality of modified fibroin fragments comprises one modification. In some embodiments, a plurality of modified fibroin fragments comprises two modifications. In some embodiments, a plurality of modified fibroin fragments comprises three modifications. In some embodiments, an asparagine to aspartic acid modification is at one or more positions selected from N23, N28, N108, N118, N136, N186, N200, N204, N240, N248, N68, N70, N77, N5262, N93, N132, N149, N172, N174, N202, N105, N4191, In some embodiments, a glutamine to glutamic acid modification is at one or more positions selected from Q24, Q149, Q202, Q58, Q139, Q275, Q5216, Q255, and Q125, In some embodiments, a methionine to methionine oxide modification is at the M64 position. In some embodiments, each modification is independently ranging in the composition between about 1% to about 99%. In some embodiments, a % modification is defined as (number of modified fibroin fragments having a modification at a specific position divided by the total number of modified fibroin fragments which include the specific position, modified or unmodified) x 100. Embodiments of the present disclosure provide a method of coating a substrate with a composite coat, the method comprising applying to the substrate a base layer coating composition through a release paper method, wherein the release paper forms a plurality of mechanically engineered topographical features on the base layer opposite to a surface applied to the substrate, wherein the engineered topographical features have width and/or depth dimensions on a scale of from about 0 µm to about 250 µm, and applying a top layer coating composition. In some embodiments, the engineered topographical features have width and/or depth dimensions on a scale of from about 0 µm to about 50 µm, from about 50 µm to about 100 µm, from about 100 µm to about 150 µm, from about 150 µm to about 200 µm, or from about 200 µm to about 250 µm. In some embodiments, the method further comprises applying to the substrate one or more additional layers coating compositions prior to applying the base layer coating composition, the additional layers selected from a preground layer, a ground layer, and an adhesive layer. In some embodiments, an adhesive layer coating composition comprises one or more of an acrylic dispersion, a polyurethane dispersion, a waterborne urethane-acrylic hybrid dispersion (HPDS), a wax, an oil in water emulsion, and/or a polysiloxane In some embodiments, a base layer coating composition comprises a protein component. In some embodiments, the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, a base layer coating composition comprises one or more of a polyurethane dispersion, a wax, an oil in water emulsion, and/or a protein binder. In some embodiments, a base layer coating composition comprises a poly lactic acid (PLA) component, and/or a poly(lactic-co-glycolic acid) (PLGA) component. In some embodiments, a base layer coating composition comprises a biodegradable polymer. In some embodiments, a top layer coating composition comprises one or more of a cellulose derivative, an aliphatic or aromatic polyurethane, a silanol/amino-polysiloxane emulsions, a crosslinked PU, treated silicas, and/or a protein component. In some embodiments, a top layer coating composition comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, corn zein, wheat gluten, pectin, chitin, casein, and/or whey. In some embodiments, a top layer coating composition a biodegradable polymer. In some embodiments, a top layer coating composition comprises a cellulose and/or cellulose derivative component. In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. In some embodiments, the cellulose derivative is ethyl cellulose. In some embodiments, the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%. In some embodiments, the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5, 1.5 to 2, 2 to 2.5, or 2.5 to 3. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%, of between about 5% and less than about 100%, of between about 10% and about 20%, between about 20% and about 30%, between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%. In some embodiments, a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%, less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%, less than about 84%, less than about 83%, less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%, less than about 71%, less than about 70%, less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%, less than about 32%, less than about 31%, less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%. In some embodiments, the substrate comprises a substantially flexible material. In some embodiments, the substrate comprises a leather material or a textile material. In some embodiments, the substrate comprises one or more of collagen, fibroin, keratin, cellulose, and/or lignin. In some embodiments, a coating composition comprises a mattifying agent. In some embodiments, a coating composition comprises a plasticizer. In some embodiments, a coating composition comprises a plurality of modified fibroin fragments, each comprising one or more amino acid residue modifications selected from an asparagine to aspartic acid modification, a glutamine to glutamic acid modification, and a methionine to methionine oxide modification. In some embodiments, a plurality of modified fibroin fragments comprises one modification. In some embodiments, a plurality of modified fibroin fragments comprises two modifications. In some embodiments, a plurality of modified fibroin fragments comprises three modifications. In some embodiments, an asparagine to aspartic acid modification is at one or more positions selected from N23, N28, N108, N118, N136, N186, N200, N204, N240, N248, N68, N70, N77, N5262, N93, N132, N149, N172, N174, N202, N105, N4191, In some embodiments, a glutamine to glutamic acid modification is at one or more positions selected from Q24, Q149, Q202, Q58, Q139, Q275, Q5216, Q255, and Q125, In some embodiments, a methionine to methionine oxide modification is at the M64 position. In some embodiments, each modification is independently ranging in the composition between about 1% to about 99%. In some embodiments, a % modification is defined as (number of modified fibroin fragments having a modification at a specific position divided by the total number of modified fibroin fragments which include the specific position, modified or unmodified) x 100. In some embodiments, a coating composition further comprises a solvent component. In some embodiments, the solvent component comprises an alcohol and/or an alcohol derivative. In some embodiments, the solvent component comprises one or more of an alcohol, an ether, a ketone, an aldehyde, and/or a ketal. In some embodiments, the solvent component is from about 75% w/w to about 99% w/w of the coating composition, from about 80% w/w to about 98% w/w of the coating composition, from about 85% w/w to about 97.5% w/w of the coating composition, or from about 85% w/w to about 95% w/w of the coating composition. In some embodiments, the solvent component comprises one or more of methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, pentanol, hexanol, acetone, butanone, methoxypropanol, di-isopropylidene glycerol, 2,2-dimethyl-4-hydroxymethyl-1,3- dioxolane, 2,2-dimethyl-1,3-dioxolane-4-methanol, or any combination thereof. In some embodiments, a coating composition comprises one or more of a polyethylene glycol (PEG) component, a polypropylene glycol (PPG) component, and/or a polyether component. In some embodiments, a coating composition comprises one or more of fatty acid or fatty acid derived amide, and/or a monoglyceride, diglyceride, and/or triglyceride. In some embodiments, a coating composition comprises one or more of a triethylene glycol monomethyl ether component, a diethylene glycol butyl ether component, a diethylene glycol ethyl ether component, a dimethyl tetradecanedioate component, an erucamide component, and/or a glyceryl stearate component. In some embodiments, a coating composition comprises water. In some embodiments, a coating composition comprises a mattifying agent. In some embodiments, a coating composition comprises a plasticizer. In some embodiments, the method further comprises one or more pressing steps, and/or one or more drying or partial drying steps. In some embodiments, a first coating composition is partially polymerized, partially dried, and/or partially cured before a second coating composition is applied. In some embodiments, a coating composition is applied at a rate from about 0.5 mL/ft² to about 5 mL/ft². In some embodiments, a coating composition is applied at a rate from about 0.5 mL/ft² to about 1 mL/ft², about 1.5 mL/ft² to about 1.5 mL/ft², about 1.5 mL/ft² to about 2 mL/ft², about 2 mL/ft² to about 2.5 mL/ft², about 2.5 mL/ft² to about 3 mL/ft², about 3 mL/ft² to about 3.5 mL/ft², about 3.5 mL/ft² to about 4 mL/ft², about 4 mL/ft² to about 4.5 mL/ft², or about 4.5 mL/ft² to about 5 mL/ft². Embodiments of the present disclosure provide an article comprising a substrate and a coating, the article made by a method of any of the embodiments described above. In some embodiments, the substrate may be a mushroom-based leather, a mesh material, a plastic material, cotton, or textiles. In some embodiments, the substrate may be a flexible or an inflexible material. Leather Article In an embodiment, the disclosure provides methods of preparing leather and leather articles coated or repaired with coating compositions described herein. In an embodiment, the coating composition comprises silk fibroin proteins or fragments thereof and a mattifying silica and/or starch. As shown in FIG.3, the following steps may be used in a leather preparation process: • Unhairing – Skins steeped in alkali solution that removes hair; • Liming – Skin is immersed in alkali/sulphide solution to alter properties of the collagen, causing it to swell and render a more open structure; • Deliming and Bateing – Enzymatic treatment that further opens the structure of the skin’s collagen; • Pickling – Acidic treatment that preserves the skins; • Tanning – Chemical process where some of the bonded collagen structures are replaced with complex ions of Chromium (wet blue leather); • Neutralizing, Dyeing and Fat Liquoring – Alkaline neutralizing solution prevents deterioration, variety of compounds are applied and react at Chromium active sites, including oil that attach themselves to the collagen fibers; • Drying – Water is removed, leather chemical properties are stabilized; and • Finishing – Surface coating is applied to ensure even color and texture of the leather. Mechanical treatments can be done before or after the finishing process to adjust material characteristics / set chemicals. The disclosure provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having an average weight average molecular weight in a range selected from between about 1 kDa and about 5 kDa, between about 5 kDa and about 10 kDa, between about 6 kDa and about 17 kDa, between about 10 kDa and about 15 kDa, between about 15 kDa and about 20 kDa, between about 17 kDa and about 39 kDa, between about 20 kDa and about 25 kDa, between about 25 kDa and about 30 kDa, between about 30 kDa and about 35 kDa, between about 35 kDa and about 40 kDa, between about 39 kDa and about 80 kDa, between about 40 kDa and about 45 kDa, between about 45 kDa and about 50 kDa, between about 60 kDa and about 100 kDa, and between about 80 kDa and about 144 kDa, and a polydispersity between 1 and about 5. In some embodiments, any other average weight average molecular weights and polydispersities described herein can be used. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between 1 and about 1.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 1.5 and about 2. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 2 and about 2.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 2.5 and about 3. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 3 and about 3.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 3.5 and about 4. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 4 and about 4.5. In some embodiments, the silk fibroin proteins or fragments thereof have a polydispersity between about 4.5 and about 5. The disclosure provides a method of coating a leather substrate with a coating composition, the method comprising applying the coating composition to one or more surfaces of the leather substrate. In some embodiments the method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments, the silk formulation further comprises about 0.001% (w/w) to about 10% (w/w) sericin relative to the silk fibroin proteins or fragments thereof. In some embodiments, the w/w ratio between silk fibroin proteins or fragments thereof and sericin is about 99:1, about 98:2, about 97:3, about 96:4, about 95:5, about 94:6, about 93:7, about 92:8, about 91:9, about 90:10, about 89:11, about 88:12, about 87:13, about 86:14, about 85:15, about 84:16, about 83:17, about 82:18, about 81:19, about 80:20, about 79:21, about 78:22, about 77:23, about 76:24, or about 75:25. In some embodiments, the relative w/w amount of sericin to the silk fibroin proteins or fragments thereof is about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, 0.4%, about 0.3%, about 0.2%, about 0.1%, about 0.01%, or about 0.001%. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments, the silk formulation further includes about 0.001% (w/v) to about 10% (w/v) sericin. In some embodiments, the silk formulation further includes about 0.001% (w/v) sericin to about 0.01% (w/v) sericin, about 0.01% (w/v) sericin to about 0.1% (w/v) sericin, about 0.1% (w/v) sericin to about 1% (w/v) sericin, or about 1% (w/v) sericin to about 10% (w/v) sericin. In some embodiments, the silk formulation further includes about 1% (w/v) sericin, about 2% (w/v) sericin, about 3% (w/v) sericin, about 4% (w/v) sericin, about 5% (w/v) sericin, about 6% (w/v) sericin, about 7% (w/v) sericin, about 8% (w/v) sericin, about 9% (w/v) sericin, about 10% (w/v) sericin, about 11% (w/v) sericin, about 12% (w/v) sericin, about 12% (w/v) sericin, about 13% (w/v) sericin, about 14% (w/v) sericin, or about 15% (w/v) sericin. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments, the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in an aqueous solution for at least 10 days prior to being formulated and applied to the leather substrate. In some embodiments, the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in an aqueous solution for at least 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 4 weeks, or 1 month. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments, the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in the formulation for at least 10 days prior to being applied to the leather substrate. In some embodiments, the silk fibroin proteins or fragments thereof do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in the formulation for at least 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 4 weeks, or 1 month. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments: 1) a portion of the silk formulation is coated on a surface of the leather substrate; or 2) a portion of the silk formulation is infused into a layer of the leather substrate; or 3) a portion of the silk formulation enters a recessed portion of the leather substrate selected from an opening, a crevice, and a defect in the leather substrate; or 4) any combination of the above. The silk formulation can be coated in any desired thickness, for example, but not limited to, about 1 µm to about 100 µm. In some embodiments, coating thickness refers to wet coating. In some embodiments, coating thickness refers to after drying coating thickness. The silk formulation can be infused in a layer of the substrate having any thickness, for example, but not limited to, about 1 µm to about 100 µm. In some embodiments, infusion layer thickness refers to wet infusion. In some embodiments, infusion layer thickness refers to after drying infusion. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation further includes a rheology modifier. In some embodiments, the rheology modifier includes one or more polysaccharides, including one or more of starch, cellulose, gum arabic, guar gum, xanthan gum, alginate, pectin, chitin, chitosan, carrageenan gum, inulin, and/or gellan gum. In some embodiments, the polysaccharides include gellan gum, including, but not limited to, low-acyl content gellan gum. In some embodiments, the w/w ratio between the silk fibroin proteins or fragments thereof and the rheology modifier in the silk formulation is about 25:1 to about 1:5. In some embodiments, the w/w ratio between the silk fibroin proteins or fragments thereof and the rheology modifier in the silk formulation is about 12:1 to about 0.1:1. In some embodiments, the w/w ratio between the silk fibroin proteins or fragments thereof and the rheology modifier in the silk formulation is about 99:1 to about 1:99. In some embodiments, the w/v concentration of the rheology modifier in the silk formulation is between about 0.01% and about 5%. In some embodiments, the w/v concentration of the rheology modifier in the silk formulation is about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, 0.4%, about 0.3%, about 0.2%, about 0.1%, about 0.01%, or about 0.001%. In some embodiments, the w/v concentration of the rheology modifier in the silk formulation is about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, or about 1%. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation further includes a plasticizer. In some embodiments, the plasticizer includes one or more polyols, and/or one or more polyethers. In some embodiments, the polyols are selected from one or more of glycol, glycerol, sorbitol, glucose, sucrose, and dextrose. In some embodiments, the polyethers are one or more polyethyleneglycols (PEGs). In some embodiments, the w/w ratio between the silk fibroin proteins or fragments thereof and the plasticizer in the silk formulation is about 5:1 to about 1:5. In some embodiments, the w/w ratio between the silk fibroin proteins or fragments thereof and the plasticizer in the silk formulation is about 99:1 to about 1:99. In some embodiments, the w/v concentration of the plasticizer in the silk formulation is between about 0.01% and about 10%.. In some embodiments, the w/v concentration of the plasticizer in the silk formulation is about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, 0.4%, about 0.3%, about 0.2%, about 0.1%, about 0.01%, or about 0.001%. In some embodiments, the w/v concentration of the plasticizer in the silk formulation is about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, or about 1%. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation further includes a defoaming agent at a concentration between about 0.001% and about 1%, between about 0.01% and about 2.5%, between about 0.1% and about 3%, between about 0.5% and about 5%, or between about 0.75% and about 7.5%. In some embodiments, the defoaming agent comprises a silicone. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation further includes a deaeration agent at a concentration between about 0.001% and about 1%, between about 0.01% and about 2.5%, between about 0.1% and about 3%, between about 0.5% and about 5%, or between about 0.75% and about 7.5%. In some embodiments, the deaeration agent comprises a silicone. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation is a liquid, a gel, a paste, a wax, or a cream. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the concentration of silk fibroin proteins or fragments thereof in the silk formulation is between about 0.1% w/v and about 15% w/v. In some embodiments, the concentration of silk fibroin proteins or fragments thereof in the silk formulation is between about 0.5% w/v and about 12% w/v. In some embodiments, the concentration of silk fibroin proteins or fragments thereof in the silk formulation is about 1% w/v, about 1.5% w/v, about 2% w/v, about 2.5% w/v, about 3% w/v, about 3.5% w/v, about 4% w/v, about 4.5% w/v, about 5% w/v, about 5.5% w/v, about 6% w/v, about 6.5% w/v, about 7% w/v, about 7.5% w/v, about 8% w/v, about 8.5% w/v, about 9% w/v, about 9.5% w/v, or about 10% w/v. In some embodiments, the concentration of silk fibroin proteins or fragments thereof in the silk formulation is about 3% w/v, about 3.25% w/v, about 3.5% w/v, about 3.75%% w/v, about 4% w/v, about 4.25% w/v, about 4.5% w/v, about 4.75% w/v, about 5% w/v, about 5.25% w/v, about 5.5% w/v, about 5.75% w/v, about 6% w/v, about 6.25% w/v, about 6.5% w/v, about 6.75% w/v, about 7% w/v, about 7.25% w/v, about 7.5% w/v, about 7.75% w/v, about 8% w/v, about 8.25% w/v, about 8.5% w/v, about 8.75% w/v, about 9% w/v, about 9.25% w/v, about 9.5% w/v, about 9.75% w/v, or about 10% w/v. In some embodiments, the concentration of silk fibroin proteins or fragments thereof in the silk formulation is between about 5 mg/mL and about 125 mg/mL. In some embodiments, the concentration of silk fibroin proteins or fragments thereof in the silk formulation is from about 10 mg/mL to about 110 mg/mL. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments the silk formulation further comprises a pH adjusting agent. In some embodiments, the pH adjusting agent includes one more of an acid and/or a base, including but not limited to, a weak acid and/or a weak base. In some embodiments, the pH adjusting agent includes one or more of ammonium hydroxide and citric acid. Any hydroxide, or weak carboxylic acid can be used interchangeably with any of the above. In some embodiments, the silk formulation has a pH of about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, or about 12. The disclosure also provides a method of treating a leather substrate with a silk formulation, the method including applying on a surface of the leather a silk formulation including silk fibroin proteins or fragments thereof having any average weight average molecular weight and polydispersity described herein, and optionally any other steps described herein, wherein in some embodiments treating the leather substrate with the silk formulation improves one or more of gloss, and/or color saturation, and/or smoothness. In some embodiments the method further comprises one or more additional steps such as dyeing the leather substrate, drying the leather substrate, mechanically stretching the leather substrate, trimming the leather substrate, performing one or more polishing steps of the leather substrate, applying a pigment to the leather substrate, applying a colorant to the leather substrate, applying an acrylic formulation to the leather substrate, chemically fixing the leather substrate, stamping the leather substrate, applying a silicone finish to the leather substrate, providing a Uniflex treatment to the leather substrate, and/or providing a Finiflex treatment to the leather substrate, wherein the step of applying the coating composition to one or more on the leather substrate is performed before, during, or after the one or more additional steps. As described herein, a silk and/or SPF composition described herein can be used before, during, or after any of these steps. In some embodiments, the leather preparation process may include the treating of the leather with a silk composition described herein. In some embodiments, the leather preparation process may include the repairing of the leather with a silk composition described herein. In some embodiments, the silk composition may include one or more chemical agents as described hereinbelow (e.g., silicone, polyurethane, etc.). In some embodiments, a silk, but also by hand-spraying, spraying using a mechanical spray setup, applying by brush, rubbing, wet-mixing, washing, drumming, soaking, injecting, plastering, smearing, or the like. In some embodiments, a silk composition described herein may be applied alone, mixed with one or several chemicals (e.g., chemical agents), as one coat, multiple coats, or defect filling composition, at multiple times using varied application methods, to leathers that have or have not been: dyed, chrome-treated, sprayed with: pigment, acrylic, fixation agents, finishing agents, and/or colorants. In some embodiments, a silk. but also by hand-spraying, spraying using a mechanical spray setup, applying by brush, rubbing, wet-mixing, washing, drumming, soaking, injecting, plastering, smearing, or the like. In some embodiments, a silk composition described herein may be applied alone, mixed with one or several chemicals (e.g., chemical agents), as one coat, multiple coats, or defect filling composition, at multiple times using varied application methods, to leathers that have or have not been: dyed, chrome-treated, sprayed with: pigment, acrylic, fixation agents, finishing agents, and/or colorants. The coating composition described herein may be applied to leather or a leather article by any of the methods described herein. In some embodiments, the coating composition described herein may be applied to a finished leather or leather article, a mechanically treated leather or leather article, or a drummed leather or leather article. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the liming step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the deliming and/or bateing steps. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the pickling step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the tanning step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the neutralizing, dyeing, and/or fat liquoring steps. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the drying step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after any finishing step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the liming step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the deliming and/or bateing steps. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the pickling step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the tanning step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the neutralizing, dyeing, and/or fat liquoring steps. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the drying step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather during the finishing step. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used during the finishing step or as part of the finishing step. In an embodiment, the coating composition described herein (with or without one or more chemical agents) may be used during the finishing step or as part of the finishing step. In another embodiment, the coating composition described herein (with or without one or more chemical agents) may be used as a stand-alone step, for example a stand-alone coating and/or repairing step. In some embodiments, the leather preparation process may include treating or repairing the leather with a chemical agent described herein below. In some embodiments, a chemical agent described herein below may be used to treat or repair leather before or after the drying step. In some embodiments, a chemical agent described herein below may be used to treat or repair leather before or after the finishing step. In some embodiments, a chemical agent described herein below may be used during the finishing step or as part of the finishing step. In some embodiments, specific leather types may include a variety of other steps. In some embodiments, the disclosure provides methods of making high-quality finished leather, for example high quality black leather, and plongé leather. With regard to the manufacturing of high-quality finished leather, for example high quality black leather, in some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the dyeing process, or as part of the dyeing process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the drying process, or as part of the drying process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the mechanical stretching process, or as part of the mechanical stretching process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the trimming process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the polishing process, or as part of the polishing process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the pigment spray process, or as part of the pigment spray process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the chemical fixation process, or as part of the chemical fixation process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the stamping process, or as part of the stamping process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the silicone- coating step of the finishing process, or as part of the silicone finishing process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the Uniflex process, or as part of the Uniflex process. With regard to the manufacturing of plongé leather, in some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the dyeing process, or as part of the dyeing process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the drying process, or as part of the drying process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the mechanical stretching process, or as part of the mechanical stretching process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the trimming process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the first polishing process, or as part of the first polishing process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the color spray process, or as part of the color spray process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the second polish process, or as part of the second polish process. In some embodiments, a silk composition described herein (with or without one or more chemical agents) may be used to treat or repair leather before or after the Finiflex process, or as part of the Finiflex process. In some embodiments, the silk compositions that may be used for coating or repairing leather and/or leather articles according to the processes described herein may include one or more silk compositions recited in Table 1. In an embodiment, the disclosure provides a method of treating or repairing leather with a silk composition described herein, wherein the method may include the steps of: dyeing the leather; mechanically stretching the leather; trimming the leather; polishing the leather; applying (optionally by spray application) a pigment, and/or an acrylic; chemically fixing the leather, stamping the leather, applying a silicone finish to the leather; and/or providing a Uniflex treatment to the leather; wherein one or more of the foregoing steps includes applying the silk composition to the leather before, during, or after the recited steps. In an embodiment, the disclosure provides a method of treating or repairing leather with a silk composition described herein, wherein the method may include the steps of: dyeing the leather, drying the leather; mechanically stretching the leather; trimming the leather; performing a first polish of the leather; applying (optionally by spray application) a colorant, and/or an acrylic; performing a second polish of the leather, and/or providing a Finiflex treatment to the leather; wherein one or more of the foregoing steps includes applying the silk composition to the leather before, during, or after the recited steps. In some embodiments of the methods described herein, silk compositions described herein may be integrated into the leather treatment processes (e.g. during, before or after: pigment + acrylic, pigment + acrylic spray, colorant spray, dyeing, fixation spray, finishing spray). In some embodiments, silk compositions described herein may be applied at any part of the larger leathering process described in FIG.3. In some embodiments of the foregoing methods, drying may be of hand or autosprayed leather materials. In some embodiments, a drying step may be provided after each and/or before each spraying of the leather material. In some embodiments, the leather materials may be dried in an oven. In some embodiments, the drying processes may be at a temperature of less than about 70, 71, 72, 73, 74, or 75 °C; or greater than about 70, 71, 72, 73, 74, or 75 °C; or about 70, 71, 72, 73, 74, or 75 °C. In some embodiments, each drying step of the leather materials may be for a period of less than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 seconds; or greater than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 seconds; or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 seconds. In some embodiments of the foregoing methods, stamping may be used during a native production process by pressing the leather material between a top plate and a bottom plate. In some embodiments, the top plate may be at an operating temperature of less than about 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or 65 °C; or greater than about 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or 65 °C; or about 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or 65 °C. In some embodiments, the stamping step may include pressing the leather material between the first and the second plates at the top plate temperature for a period of less than about 1, 2, 3, 4, or 5 seconds; or greater than about 1, 2, 3, 4, or 5 seconds; or about 1, 2, 3, 4, or 5 seconds. In some embodiments, the stamping step may include pressing the leather material between the first and the second plates at the top plate temperature at a pressure of about 75 to about 125 kg/cm², or about 90 to about 110 kg/cm², or about 100 kg/cm². In some embodiments of the foregoing methods, the Finiflex treatment may include compressing the leather material between two heated rotating metallic wheels at a temperature of about 75 to about 125 °C, or about 93 °C, at a pressure of about 5 to about 30 kg/m², or about 20 kg/m², and for a period of about 1 to about 10 seconds, or about 4 seconds. In some embodiments of the foregoing methods, the Uniflex treatment includes pressing the leather material through two pressing cylinders, where the top cylinder is heated to a temperature of about 50 to about 100 °C, or about 60 °C, while the bottom cylinder may be unheated, and the two cylinders compress the leather material at about 10 to about 50 bar, or about 30 bar, for a period of about 1 to about 10 seconds, or about 3 to about 5 seconds. In some embodiments, coated leather materials prepared by the foregoing methods may undergo mechanical quality testing according to one or more of a Veslic Process, a Martindale Process, a Water Drop Process, a Hydration Test, and a UV Test. Veslic Process – Dry (n = 50) and wet (n = 10) cycles performed at f = 1.0 Hz, 1 cm² abrasion cube applied at 1 kg/cm². Visually scored 0-5 (leather and abrasion cube) based on how much color rubs off the leather and onto cube. In some embodiments, dry cycles may from 0-100; wet cycles may be from 0-30; frequency may be from 0.1 – 2 Hz; and pressure may be from 0-5 kg/cm². Martindale Process – 11 cm² circular cuts of leather samples are rubbed against an abrasive in a lissajous figure pattern (Bowditch curve shape) for n = 1500 cycles at a frequency of 0.66 – 1.0 Hz at 9 kPa. Visually scored 0-5 based on how much color rubs off the leather and onto cube. In some embodiments, the cycles may be from 0-5000; frequency may be from 0.1 – 2 Hz; and pressure may be from 0-50 kPa. Water Drop Process – 2-4 droplets are allowed to run the length of a vertically- oriented leather sample; after 1 minute the sample is judged negatively if water streaks remain on the surface. Visually scored 0-5 based on appearance of water streaks on the leather. Hydration Test – Two circular replicants of the same leather sample are pressed surface-to-surface by a 300 g weight in a humidity chamber (90% Residual Humidity; 50 °C) for 72 hr. Scored based on how easily samples separate from one another after testing and if any color rubs off. In some embodiments, the weight may be from 0-1 kg; the residual humidity may be from 70-95%; the temperature may be from 40-80 °C; and time may be from 24-100 hr. UV Test – Samples are placed under UV light for 25 hr and observed for color loss. Xe lamp: 42 W/m², 50 °C, λ_incident = 300-400 nm. Visually scored 0-5 based on how much color fades out of the leather over the testing period. In some embodiments, the time may be from 20-40 hr; lamp intensity may be from 20-60 W/m²; temperature may be from 40-80 °C; and the λ_incident may be about 250-450 nm. In one embodiment, applying the mattifying coating composition described herein at the finishing stage (high-quality finished process) provides a leather article with a matte look. In another embodiment, applying the water soluble dye fixing coating composition described herein at the finishing stage (high-quality finished process) provides a leather article dyed with the water soluble dye. In one embodiment, the leather article is an aniline leather article dyed with a water soluble aniline leather dye. Polyamidamine Dendrimer for Adhering Silk Fibroin Fragments Compositions to a Cellulose Derivative In some embodiments, a polyamidamine compound, e.g., a dendrimer, could be used to adhere silk fibroin fragments compositions or any other coating composition to a cellulose derivative composition and/or coating. In some embodiments, the polyamidamine compound is Cartaretin F liquid, an aqueous solution of a polyamidamine. In some embodiments, the polyamidamine compound is cationic. In some embodiments, the cellulose derivative is methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or microcrystalline cellulose. In some embodiments, the polyamidamine dendrimer is diluted to a concentration of 0% to 0.1%, 0.1% to 0.2%, 0.2% to 0.3%, 0.3% to 0.4%, 0.4% to 0.5%, 0.5% to 0.6%, 0.6% to 0.7%, 0.7% to 0.8%, 0.8% to 0.9%, 0.9% to 1.0%, 1.0% to 1.1%, 1.1% to 1.2%, 1.2% to 1.3%, 1.3% to 1.4%, or 1.4% to 1.5%. In some embodiments, the dosage of the polyamidamine dendrimer is 0.05% to 0.10%, 0.10% to 0.15%, 0.15% to 0.20%, 0.20% to 0.25%, 0.25% to 0.30%, 0.30% to 0.35%, 0.35% to 0.40%, 0.40% to 0.45%, or 0.45% to 0.50%. In some embodiments, silk may be used to finish or repair a leather variant requiring lighter coloring treatment. The lighter volumes of colorant and pigment used may render silk more effective at locking in color. In some embodiments, silk may be used at the wet stages of high-quality finished leather processing (e.g., in the small volume mixing drum) to replace another chemical during the colorant mixing stage. In some embodiments, a silk wax may be used (or other silk composition described herein) to remove defects/holes in the raw leather (stemming from a follicle or a feed-stock related defect) through application of the silk material onto the skin along any point in the treatment process. If done early in the process, it may be used to change the quality classification of the pre-treated leather to be selected to make a high-quality end product. This effectively provides increased yield (amount of usable leather for a given quality of end product). Dye Assistant In some embodiments, a dye assistant (e.g., Optifix E50 liq.) is used to improve the wet-fastness properties of dyed leather. In some embodiments the dyeing assistant is an aliphatic polyamine. In some embodiments the aliphatic polyamine is cationic. The dye assistant can either be applied after the treatment of the dyed leather or intermediately (top dyeing). In some embodiments, the dye assistant is applied in the wet-end stage. In some embodiments the dye assistant is applied at 30° C , 35° C, 40° C, 45° C, or 50° C. In some embodiments the dye assistant is applied with an acid (eg., formic acid) and water. Mushroom-Based Material In some embodiments, the substrate comprises, without limitation, a mycological material, a mushroom-based material, a mycelium-based material, or a fungal-based material, and/or a like material. All terms, including without limitations, a mycological material, a mushroom-based material, a mycelium-based material, a fungal-based material, are used herein interchangeably As used herein, unless otherwise specified, the term “mycological material,” “mushroom-based material,” “mycelium-based material,” “fungal-based material,” and “fungal biomass” refers in certain embodiments to a mass of a fungus that has been cultured, fermented, or grown by any suitable process. In some embodiments, it is to be expressly understood that a fungal biomass may be produced by any of a number of methods known in the art, including but not limited to surface fermentation methods, submerged fermentation methods, solid-substrate submerged fermentation (SSSF) methods. In some embodiments, fungal leather analog materials made from inactivated fungal biomass. Additionally, leather analog materials according to the present disclosure may be biodegradable, i.e. biodegrade more quickly under a given set of conditions than true leather. Plant-Based Material In some embodiments, the substrate comprises, without limitation, a plant- based material. Some non-limiting examples of sources for a plant-based leather include, pineapples, corn, bananas, apples, cacti, green tea, coffee grounds, coconut water, flowers, palm leaves, cork, grapes, kombucha, leaves, paper, cotton, cool stone, tree bark, washi, agave, nettles, and hemp plant. Additionally, plant-based leather materials according to the present disclosure may be biodegradable, i.e. biodegrade more quickly under a given set of conditions than true leather. Edible Materials In some embodiments, the substrate comprises, without limitation, edible materials, or foodstuff. In some embodiments, the foodstuff is selected from the group consisting of powdery food, dry solid food, oily food, perishable good, vegetable, fruit, meat, egg, and seafood. In some embodiments, the perishable good is selected from vegetable, fruit, meat, egg, and seafood. In some embodiments, the perishable good is selected from the group consisting of vegetable and fruit. In some embodiments, the perishable good is vegetable. In some embodiments, the vegetable is carrot. In some embodiments, the perishable good is fruit. In some embodiments, the fruit is selected from the group consisting of strawberry, orange, apple, pear, plum, banana, grape, and grapefruit. In some embodiments, the fruit is any berry known in the art. In some embodiments, the fruit is any drupe known in the art. In some embodiments, the fruit is any pome known in the art. In some embodiments, the fruit is any citrus known in the art. In some embodiments, the fruit is any melon known in the art. In some embodiments, the fruit is any dried fruit known in the art, such as raisins, prunes, dates, apricots, etc. In some embodiments, the fruit is any stone fruit known in the art. In some embodiments, the perishable good is any vegetable known in the art. In some embodiments, the perishable good is any seed known in the art. In some embodiments, the perishable good is meat. In some embodiments, the meat is poultry, pork, beef, veal, lamb, bison, ostrich, rabbit, game, fish, eel, shellfish, or seafood. In some embodiments, the poultry is selected from the group consisting of poultry chicken, turkey, duck, goose, and pigeon. Textiles In some embodiments, the substrate comprises, without limitation, textiles. In an embodiment, a textile comprises a synthetic textile, including polyester, Mylar, cotton, nylon, polyester-polyurethane copolymer, rayon, acetate, aramid (aromatic polyamide), acrylic, ingeo (polylactide), lurex (polyamide-polyester), olefin (polyethylene-polypropylene), and combinations thereof. In an embodiment, a textile comprises a natural textile, including alpaca fiber, alpaca fleece, alpaca wool, lama fiber, lama fleece, lama wool, cotton, cashmere and sheep fiber, sheep fleece, sheep wool. Fillers and Particles In some embodiments, the coating system comprises, without limitation, fillers. In some embodiments, the filler is selected from the group consisting of starch-derived filler, calcium carbonate, calcite, aragonite, vaterite, amorphous alumina, alumino-silicate, talc, clay, kaolin, sepiolite, palygorskite, and combinations thereof. In some embodiments, the coating system comprises, without limitation, particles. The the particle may include polymeric particle, mica, silica, mud, and clay. In some embodiments, the substrate comprises clay particles. Throughout this specification, the term “clay” is intended to mean fine-grained earthy materials that become plastic when mixed with water. The clay may be a natural, synthetic or chemically modified clay. Clays include hydrous aluminum silicates that contain impurities, e.g. potassium, sodium, magnesium, or iron in small amounts. In one embodiment, the clay is a material containing from 38.8 % to 98.2 % of SiO2 and from 0.3 % to 38.0 % of Al2O3, and further contains one or more of metal oxides selected from Fe2O3, CaO, MgO, TiO2, ZrO2, Na2O and K2O. In some embodiments, the clay has a layered structure comprising hydrous sheets of octahedrally coordinated aluminium, magnesium or iron, or of tetrahedrally coordinated silicon. In one embodiment, the clay is selected from the group consisting of kaolin, talc, 2:1 phyllosilicates, 1:1 phyllosilicates, smectite, bentonite, montmorillonites (also known as bentonites), hectorites, volchonskoites, nontronites, saponites, beidelites, sauconites, and mixtures thereof. In one embodiment, the clay is kaolin or bentonite. In some embodiments, the clay is a synthetic hectorite. In another embodiment, the clay is a bentonite. In some embodiments, the clays have a cation exchange capacity of from about 0.7 meq/100 g to about 150 meq/100 g. In some embodiments, the clays have a cation exchange capacity of from about 30 meq/100 g to about 100 meq/100 g. In some embodiments, the coating system optionally comprise a composite particle having an anionically charged clay electrostatically complexed with the cationically charged skin conditioning agents as disclosed herein. Commercially available synthetic hectorites include those products sold under the trade names Laponite® RD, Laponite® RDS, Laponite® XLG, Laponite® XLS, Laponite® D, Laponite® DF, Laponite® DS, Laponite® S, and Laponite® JS (Southern Clay products, Texas, USA). Commercially available bentonites include those products sold under the trade names Gelwhite® GP, Gelwhite® H, Gelwhite® L, Mineral Colloid® BP, Mineral Colloid® MO, Gelwhite® MAS 100 (sc) , Gelwhite® MAS 101, Gelwhite® MAS 102, Gelwhite® MAS 103, Bentolite® WH, Bentolite® L10, Bentolite® H, Bentolite® L, Permont® SX10A, Permont® SC20, and Permont® HN24 (Southern Clay Products, Texas, USA); Bentone® EW and Bentone® MA (Dow Corning); and Bentonite® USP BL 670 and Bentolite® H4430 (Whitaker, Clarke & Daniels). In some embodiments, the coating system further comprises a powder component selected from the group consisting of clay mineral powders such as talc, mica, sericite, silica, magnesium silicate, synthetic fluorophlogopite, calcium silicate, aluminum silicate, bentonite, montmorillonite; pearl powders such as alumina, barium sulfate, calcium secondary phosphate, calcium carbonate, titanium oxide, zirconium oxide, zinc oxide, hydroxy apatite, iron oxide, iron titanate, ultramarine blue, Prussian blue, chromium oxide, chromium hydroxide, cobalt oxide, cobalt titanate, titanium oxide coated mica; organic powders such as polyester, polyethylene, polystyrene, methyl methacrylate resin, cellulose, 12-nylon, 6-nylon, styrene-acrylic acid copolymers, polypropylene, vinyl chloride polymer, tetrafluoroethylene polymer, boron nitride, fish scale guanine, laked tar color dyes, laked natural color dyes, spherical alumina, polyacrylates, silicates, sulfates, metal dioxides, carbonates, celluloses, polyalkylenes, vinyl acetates, polystyrenes, polyamides, acrylic acid ethers, silicones, and combinations thereof. Coating System Additives In some embodiments, the coating system further comprises an additive selected from the group consisting of an antioxidant, a synthetic emulsifier, a solvent, a colorant, a surfactant (e.g., sophorolipid), an astringent, a plant extract, an essential oil, a coolant, a humectant, a moisturizer, a structurant, a gelling agent, a sequestering agent, a preserving agent, a filler, a fragrance, a thickener, a wetting agent, a dye, a pigment, a glitter, and combinations thereof. Chemical Agents for Use with Leather and Leather Articles Coated with Silk Fibroin-Based Protein Fragments In certain embodiments, chemical agents may be used to pretreat, treat, and/or post- treat a leather or leather article described herein. In some embodiments, the silk and/or SPF solutions (e.g., SFS), or compositions, described herein, may include one or more of the chemical agents described herein. In some embodiments, the silk and/or SPF solutions or compositions described herein, may replace one or more of the chemical agents described herein. In some embodiments, the chemical agents may be selected from the group consisting of silicone, casein, an acidic agent, a dyeing agent, a pigment dye, a traditional finishing agent, and a technical finishing agent. In some embodiments, chemical agents may include one or more agents recited in Table 2. In some embodiments, the chemical agent may be selected from the group consisting of aqueous lacquers, waxes, oils, binders (protein or other), fillers, hand-modifiers, levelling agents, solvent lacquers, water-based lacquers, penetrators, acrylic resins, butadiene resins, compact resins, hybrid resins, impregnation resins, rheology modifiers, solvent dullers, solvent urethanes, water-based dullers, water- based topcoats, chromes, acidic dyes, basic dyes, dyes (chromium-based or other), colorants, and combinations thereof. In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a wetting agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a wetting agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a wetting agent. In an embodiment, the wetting agent improves one or more coating properties. Suitable wetting agents are known to those of skill in the art. Exemplary, non-limiting examples of wetting agents from a representative supplier, Lamberti SPA, are given in the following table. Imbitex Imbitex Imbitex Tensola liq. Imbitex

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a detergent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a detergent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a detergent. In an embodiment, the detergent improves one or more coating properties. Suitable detergents are known to those of skill in the art. Exemplary, non-limiting examples of detergents from a representative supplier, Lamberti SPA, are given in the following table. Biorol Biorol J Biorol Biorol Cesapo liq. Cesapo

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a sequestering or dispersing agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a sequestering or dispersing agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a sequestering or dispersing agent. Suitable sequestering or dispersing agents are known to those of skill in the art. Exemplary, non-limiting examples of sequestering or dispersing agents from a representative supplier, Lamberti SPA, are given in the following table. Lamega Chelam Lamega

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an enzyme. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an enzyme. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an enzyme. Suitable enzymes are known to those of skill in the art. Exemplary, non-limiting examples of enzymes from a representative supplier, Lamberti SPA, are given in the following table. Lazim Lazim P

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a bleaching agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a bleaching agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with a bleaching agent. Suitable bleaching agents are known to those of skill in the art. Exemplary, non-limiting examples of bleaching agents from a representative supplier, Lamberti SPA, are given in the following table. Stabilox conc.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an antifoaming agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an antifoaming agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an antifoaming agent. Suitable antifoaming agents are known to those of skill in the art. Exemplary, non- limiting examples of antifoaming agents from a representative supplier, Lamberti SPA, are given in the following table. Antifoa Defome Defome

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an anti-creasing agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an anti-creasing agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is pretreated with an anti-creasing agent. Suitable anti-creasing agents are known to those of skill in the art. Exemplary, non- limiting examples of anti-creasing agents from a representative supplier, Lamberti SPA, are given in the following table. Lubisol

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye dispersing agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye dispersing agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye dispersing agent. Suitable dye dispersing agents are known to those of skill in the art. Exemplary, non-limiting examples of dye dispersing agents from a representative supplier, Lamberti SPA, are given in the following table. Lamegal Lamegal Lamegal Lamegal

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye leveling agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye leveling agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye leveling agent. Suitable dye leveling agents are known to those of skill in the art. Exemplary, non-limiting examples of dye leveling agents from a representative supplier, Lamberti SPA, are given in the following table. Lamegal

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye fixing agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye fixing agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye fixing agent. Suitable dye fixing agents are known to those of skill in the art. Exemplary, non-limiting examples of dye fixing agents from a representative supplier, Lamberti SPA, are given in the following table. Lamfix L Lamfix L Lamfix P

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye special resin agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye special resin agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye special resin agent. Suitable dye special resin agents are known to those of skill in the art. Exemplary, non- limiting examples of dye special resin agents from a representative supplier, Lamberti SPA, are given in the following table. Denifast Cobral D

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye anti-reducing agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye anti-reducing agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a dye anti-reducing agent. Suitable dye anti-reducing agents are known to those of skill in the art. Exemplary, non-limiting examples of dye anti-reducing agents from a representative supplier, Lamberti SPA, are given in the following table. Lam Lam

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system anti-migrating agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system anti-migrating agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system anti-migrating agent. Suitable pigment dye system anti-migrating agents are known to those of skill in the art. Exemplary, non-limiting examples of pigment dye system anti-migrating agents from a representative supplier, Lamberti SPA, are given in the following table. Neopat Co 96/m conc

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system binder. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system binder. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system binder. Suitable pigment dye system binders are known to those of skill in the art. Exemplary, non-limiting examples of pigment dye system binders from a representative supplier, Lamberti SPA, are given in the following table. Neopat Bi conc.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system binder and anti-migrating agent combination. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a pigment dye system binder and anti-migrating agent combination. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with pigment dye system binder and anti-migrating agent combination. Suitable pigment dye system binder and anti- migrating agent combinations are known to those of skill in the art. Exemplary, non-limiting examples of pigment dye system binder and anti-migrating agent combinations from a representative supplier, Lamberti SPA, are given in the following table. Neopat Co PK1

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a delave agent. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a delave agent. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is treated with a delave agent. Suitable delave agents are known to those of skill in the art. Exemplary, non-limiting examples of delave agents from a representative supplier, Lamberti SPA, are given in the following table. Neopat co

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a wrinkle free treatment. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a wrinkle free treatment. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a wrinkle free treatment. Suitable wrinkle free treatments are known to those of skill in the art. Exemplary, non-limiting examples of wrinkle free treatments from a representative supplier, Lamberti SPA, are given in the following table. Cel Pol Ro

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a softener. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a softener. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a softener. Suitable softeners are known to those of skill in the art. Exemplary, non-limiting examples of softeners from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a handle modifier. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a handle modifier. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a handle modifier. Suitable handle modifiers are known to those of skill in the art. Exemplary, non-limiting examples of handle modifiers from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a waterborne polyurethane (PU) dispersion. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a waterborne polyurethane (PU) dispersion. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a waterborne polyurethane (PU) dispersion. Suitable waterborne polyurethane dispersions for traditional finishing are known to those of skill in the art. Exemplary, non-limiting examples of waterborne polyurethane dispersions for traditional finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a finishing resin. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a finishing resin. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is traditionally finished with a finishing resin. Suitable finishing resins are known to those of skill in the art. Exemplary, non-limiting examples of finishing resins from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a waterborne polyurethane dispersion. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a waterborne polyurethane dispersion. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a waterborne polyurethane dispersion. Suitable waterborne polyurethane dispersions for technical finishing are known to those of skill in the art. Exemplary, non-limiting examples of waterborne polyurethane dispersions for technical finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with an oil or water repellant. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with an oil or water repellant. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with an oil or water repellant. Suitable oil or water repellants for technical finishing are known to those of skill in the art. Exemplary, non-limiting examples of oil or water repellants for technical finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a flame retardant. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a flame retardant. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a flame retardant. Suitable flame retardants for technical finishing are known to those of skill in the art. Exemplary, non-limiting examples of flame retardants for technical finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a crosslinker. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a crosslinker. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a crosslinker. Suitable crosslinkers for technical finishing are known to those of skill in the art. Exemplary, non-limiting examples of crosslinkers for technical finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a thickener for technical finishing. In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a thickener for technical finishing. In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is technically finished with a thickener for technical finishing. Suitable thickeners for technical finishing are known to those of skill in the art. Exemplary, non-limiting examples of thickeners for technical finishing from a representative supplier, Lamberti SPA, are given in the following table.

In an embodiment, the disclosure provides a leather or leather article processed with a composition comprising silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is finished with one or more of Silky Top 7425 NF, Uniseal 9049, Unithane 351 NF, and Unithane 2132 NF (Union Specialties, Inc.). In an embodiment, the disclosure provides a leather or leather article having a coating, wherein the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is finished with one or more of Silky Top 7425 NF, Uniseal 9049, Unithane 351 NF, and Unithane 2132 NF (Union Specialties, Inc.). In an embodiment, the disclosure provides a leather or leather article including a defect repairing filling, wherein the filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa, wherein the leather or leather article is finished with one or more of Silky Top 7425 NF, Uniseal 9049, Unithane 351 NF, and Unithane 2132 NF (Union Specialties, Inc.). Other suitable Union Specialties products such as finishes, additive, and/or oils and waxes are known to those of skill in the art. Exemplary, non-limiting examples of Union Specialties products are given in the following table:

In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa. In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 6 kDa to about 17 kDa. In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 17 kDa to about 39 kDa. In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 39 kDa to about 80 kDa. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 6 kDa to about 17 kDa. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 17 kDa to about 39 kDa. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 39 kDa to about 80 kDa. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 5 kDa to about 144 kDa. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 6 kDa to about 17 kDa. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 17 kDa to about 39 kDa. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof having an average weight average molecular weight range of about 39 kDa to about 80 kDa. In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof a low molecular weight silk. In any of the foregoing leather or leather article embodiments, the processing composition comprises a medium molecular weight silk. In any of the foregoing leather or leather article embodiments, the processing composition comprises a heavy molecular weight silk. In any of the foregoing leather or leather article embodiments, the processing composition comprises silk based proteins or fragments thereof that comprise one or more of low, medium, and high molecular weight silk. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof a low molecular weight silk. In any of the foregoing leather or leather article embodiments, the coating comprises a medium molecular weight silk. In any of the foregoing leather or leather article embodiments, the coating comprises a heavy molecular weight silk. In any of the foregoing leather or leather article embodiments, the coating comprises silk based proteins or fragments thereof that comprise one or more of low, medium, and high molecular weight silk. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof a low molecular weight silk. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises a medium molecular weight silk. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises a heavy molecular weight silk. In any of the foregoing leather or leather article embodiments, the defect repairing filling comprises silk based proteins or fragments thereof that comprise one or more of low, medium, and high molecular weight silk. In any of the foregoing leather or leather article embodiments, the silk based proteins or protein fragments thereof have an average weight average molecular weight range selected from the group consisting of about 5 to about 10 kDa, about 6 kDa to about 17 kDa, about 17 kDa to about 39 kDa, about 39 kDa to about 80 kDa, about 60 to about 100 kDa, and about 80 kDa to about 144 kDa, wherein the silk based proteins or fragments thereof have a polydispersity of between about 1.5 and about 3.0, and optionally wherein the proteins or protein fragments, prior to processing, coating, and/or repairing the leather or leather article, do not spontaneously or gradually gelate and do not visibly change in color or turbidity when in a solution for at least 10 days. Processes for Production of Silk Fibroin-Based Protein Fragments and Solutions Thereof As used herein, the term “fibroin” includes silkworm fibroin and insect or spider silk protein. In an embodiment, fibroin is obtained from Bombyx mori. In an embodiment, the spider silk protein is selected from the group consisting of swathing silk (Achniform gland silk), egg sac silk (Cylindriform gland silk), egg case silk (Tubuliform silk), non-sticky dragline silk (Ampullate gland silk), attaching thread silk (Pyriform gland silk), sticky silk core fibers (Flagelliform gland silk), and sticky silk outer fibers (Aggregate gland silk). The silk based proteins or fragments thereof, silk solutions or mixtures (e.g., SPF or SFS solutions or mixture), and the like, may be prepared according to the methods described in U.S. Patent Nos.9,187,538, 9,522,107, 9,522,108, 9,511,012, 9,517,191, 9,545,369, and 10,166,177, and U.S. Patent Publication Nos.2016/0222579 and 2016/0281294, and International Patent Publication Nos. WO 2016/090055 and WO 2017/011679, the entirety of which are incorporated herein by reference. In some embodiments, the silk based proteins or fragments thereof may be provided as a silk composition, which may be an aqueous solution or mixture of silk, a silk gel, and/or a silk wax as described herein. Methods of using silk fibroin or silk fibroin fragments in coating applications are known and are described for example in U.S. Patents Nos.10,287,728 and 10,301,768. Following are non-limiting examples of suitable ranges for various parameters in and for preparation of the silk solutions and/or compositions of the present disclosure. The silk solutions of the present disclosure may include one or more, but not necessarily all, of these parameters and may be prepared using various combinations of ranges of such parameters. In an embodiment, the percent sericin in the solution or composition is non-detectable to 30%. In an embodiment, the percent sericin in the solution or composition is non- detectable to 5%. In an embodiment, the percent sericin in the solution or composition is 1%. In an embodiment, the percent sericin in the solution or composition is 2%. In an embodiment, the percent sericin in the solution or composition is 3%. In an embodiment, the percent sericin in the solution or composition is 4%. In an embodiment, the percent sericin in the solution or composition is 5%. In an embodiment, the percent sericin in the solution or composition is 10%. In an embodiment, the percent sericin in the solution or composition is 30%. In an embodiment, a solution or composition of the present disclosure includes pure silk fibroin-based protein fragments having an average weight average molecular weight ranging from 6 kDa to 17 kDa. In an embodiment, a solution or composition of the present disclosure includes pure silk fibroin-based protein fragments having an average weight average molecular weight ranging from 17 kDa to 39 kDa. In an embodiment, a solution or composition of the present disclosure includes pure silk fibroin-based protein fragments having an average weight average molecular weight ranging from 39 kDa to 80 kDa. In an embodiment, a composition of the present disclosure includes silk protein fragments having an average weight average molecular weight ranging from 6 kDa to 17 kDa. In an embodiment, a composition of the present disclosure includes silk protein fragments having an average weight average molecular weight ranging from 17 kDa to 39 kDa. In an embodiment, a composition of the present disclosure includes silk protein fragments having an average weight average molecular weight ranging from 39 kDa to 80 kDa. In an embodiment, a composition of the present disclosure includes silk protein fragments having an average weight average molecular weight of about 1 kDa to about 350 kDa, or about 1 kDa to about 300 kDa, or about 1 kDa to about 250 kDa, or about 1 kDa to about 200 kDa, or about 1 kDa to about 150 kDa, or about 1 kDa to about 100 kDa, or about 1 kDa to about 50 kDa, or about 1 kDa to about 25 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have having an average weight average molecular weight ranging from 1 kDa to 6 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have an average weight average molecular weight ranging from 6 kDa to 16 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have an average weight average molecular weight ranging from 16 kDa to 38 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have an average weight average molecular weight ranging from 38 kDa to 80 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have an average weight average molecular weight ranging from 80 kDa to 150 kDa. In an embodiment, silk fibroin-based protein fragments incorporated into the silk compositions described herein have an average weight average molecular weight ranging from 1 kDa to 250 kDa. In some embodiments, the silk compositions provided herein may be applied as mixtures to an article to be processed or in stepwise processes to the article. For example, a silk composition that includes low molecular weight silk and medium molecular weight silk may be applied to an article to be processed. Alternatively, a low molecular weight silk composition may be applied to an article to be processed, as provided by the processes described herein, and then a medium or high molecular weight silk may then be applied to the article. The low, medium, and high molecular weight silk compositions may be added in any order or any combination (e.g., low/med, low/high, med/high, low/med/high). In some embodiments, the silk compositions provided herein may be applied as mixtures to an article to be coated or in stepwise processes to form coating layers on the article. For example, a silk composition that includes low molecular weight silk and medium molecular weight silk may be applied to an article to be coated. Alternatively, a low molecular weight silk composition may be applied to an article to be coated, as provided by the processes described herein, and then a medium or high molecular weight silk may then be applied to the article. The low, medium, and high molecular weight silk compositions may be added in any order or any combination (e.g., low/med, low/high, med/high, low/med/high). In some embodiments, the silk compositions provided herein may be applied as mixtures to an article to be repaired or in stepwise processes to form fillings in or on the article. For example, a silk composition that includes low molecular weight silk and medium molecular weight silk may be applied to an article to be repaired. Alternatively, a low molecular weight silk composition may be applied to an article to be repaired, as provided by the processes described herein, and then a medium or high molecular weight silk may then be applied to the article. The low, medium, and high molecular weight silk compositions may be added in any order or any combination (e.g., low/med, low/high, med/high, low/med/high). In some embodiments, where multiple layers of silk compositions are applied to an article to be coated, they may have at least one layer, or 1 layer to 1 million layers, or 1 layer to 100,000 layers, or 1 layer to 10,000 layers, or 1 layer to 1,000 layers of such silk compositions, wherein the layers may have the same or different thicknesses. For example, in some embodiments, the layers may have a thickness of from about 1 nm to about 1 mm, or about 1 nm to about 1 µm, or about 1 nm to about 500 nm, or about 1 nm to about 400 nm, or about 1 nm to about 300 nm, or about 1 nm to about 200 nm, or about 1 nm to about 100 nm, or about 1 nm to about 75 nm, or about 1 nm to about 50 nm, or about 1 nm to about 25 nm, or about 1 nm to about 20 nm, or about 1 nm to about 15 nm, or about 1 nm to about 10 nm, or about 1 nm to about 5 nm. In an embodiment, a composition of the present disclosure having pure silk fibroin- based protein fragments has a polydispersity ranging from about 1 to about 5.0. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments has a polydispersity ranging from about 1.5 to about 3.0. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments has a polydispersity ranging from about 1 to about 1.5. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments has a polydispersity ranging from about 1.5 to about 2.0. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments has a polydispersity ranging from about 2.0 to about 2.5. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments, has a polydispersity ranging from about is 2.0 to about 3.0. In an embodiment, a composition of the present disclosure having pure silk fibroin-based protein fragments, has a polydispersity ranging from about is 2.5 to about 3.0. In an embodiment, a composition of the present disclosure having silk protein fragments has a polydispersity ranging from about 1 to about 5.0. In an embodiment, a composition of the present disclosure having silk protein fragments has a polydispersity ranging from about 1.5 to about 3.0. In an embodiment, a composition of the present disclosure having silk protein fragments has a polydispersity ranging from about 1 to about 1.5. In an embodiment, a composition of the present disclosure having silk protein fragments has a polydispersity ranging from about 1.5 to about 2.0. In an embodiment, a composition of the present disclosure having silk protein fragments has a polydispersity ranging from about 2.0 to about 2.5. In an embodiment, a composition of the present disclosure having silk protein fragments, has a polydispersity ranging from about is 2.0 to about 3.0. In an embodiment, a composition of the present disclosure having silk protein fragments, has a polydispersity ranging from about is 2.5 to about 3.0. In some embodiments the polydispersity of low molecular weight silk protein fragments may be about 1 to about 5.0, or about 1.5 to about 3.0, or about 1 to about 1.5, or about 1.5 to about 2.0, or about 2.0 to about 2.5, or about 2.5 to about 3.0. In some embodiments the polydispersity of medium molecular weight silk protein fragments may be about 1 to about 5.0, or about 1.5 to about 3.0, or about 1 to about 1.5, or about 1.5 to about 2.0, or about 2.0 to about 2.5, or about 2.5 to about 3.0. In some embodiments the polydispersity of high molecular weight silk protein fragments may be about 1 to about 5.0, or about 1.5 to about 3.0, or about 1 to about 1.5, or about 1.5 to about 2.0, or about 2.0 to about 2.5, or about 2.5 to about 3.0. In some embodiments, in compositions described herein having combinations of low, medium, and/or high molecular weight silk protein fragments, such low, medium, and/or high molecular weight silk proteins may have the same or different polydispersities. Bio-Based Polyurethane In some embodiments, the coating system comprises, without limitation, a bio-based polyurethane. In some embodiments, the bio-based polyurethane is biodegradable. Biodegradable polyurethanes can be obtained using biodegradable soft segments and isomannide hard segments. In the biodegradable soft segment, polyurethanes, such as those containing poly(^-caprolactone) (PCL), have been obtained, along with poly(ethylene oxide) (PEO) and poly(l-lactide) PLA. In the biodegradable hard segments, the diisocyanate and the chain extender can be designed from a variety of biologically relevant molecules. Some non- limiting examples of bio-based polyurethanes are further described in sciencedirect.com/topics/engineering/biodegradable-polyurethane and ncbi.nlm.nih.gov/pmc/articles/PMC4108296/. Compositions and Processes Including Silk Fibroin-Based Processing Compositions, Coatings, or Fillings In an embodiment, the disclosure may include leather or leather articles that may be processed, coated, or repaired with an SPF mixture solution (i.e., silk fibroin solution (SFS)), and/or composition, as described herein to produce a processed, coated, or repaired article. In an embodiment, the processed, coated, or repaired articles described herein may be treated with additional chemical agents that may enhance the properties of the coated article. In an embodiment, the SFS may enhance the properties of the coated or repaired article, or the SFS may include one or more chemical agents that may enhance the properties of the coated or repaired article. In some embodiments, chemical finishes may be applied to leather or leather articles before or after such leather or leather articles are processed, coated, or repaired with SFS. In an embodiment, chemical finishing may be intended as the application of chemical agents and/or SFS to leather or leather articles to modify the original leather’s or leather articles’ properties and achieve properties in the leather or leather articles that would be otherwise absent. With chemical finishes, leather or leather articles treated with such chemical finishes may act as surface treatments and/or the treatments may modify the elemental analysis of treated leather or leather article base polymers. In an embodiment, a type of chemical finishing may include the application of certain silk-fibroin based solutions to leather or leather articles. For example, SFS may be applied to a leather or leather article after it is dyed, but there are also scenarios that may require the application of SFS during processing, during dyeing, or after a garment is assembled from a selected leather or leather article. In some embodiments, after its application, SFS may be dried with the use of heat. In some embodiments, SFS may then be fixed to the surface of the leather or leather article in a processing step called curing. In some embodiments, SFS may be supplied in a concentrated form suspended in water. In some embodiments, SFS may have a concentration by weight (% w/w or % w/v) or by volume (v/v) of less than about 50 %, or less than about 45%, or less than about 40%, or less than about 35%, or less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 4%, or less than about 3%, or less than about 2%, or less than about 1%, or less than about 0.1%, or less than about 0.01%, or less than about 0.001%, or less than about 0.0001%, or less than about 0.00001%. In some embodiments, SFS may have a concentration by weight (% w/w or % w/v) or by volume (v/v) of greater than about 50 %, or greater than about 45%, or greater than about 40%, or greater than about 35%, or greater than about 30%, or greater than about 25%, or greater than about 20%, or greater than about 15%, or greater than about 10%, or greater than about 5%, or greater than about 4%, or greater than about 3%, or greater than about 2%, or greater than about 1%, or greater than about 0.1%, or greater than about 0.01%, or greater than about 0.001%, or greater than about 0.0001%, or greater than about 0.00001%. In some embodiments, the solution concentration and the wet pick of the material determines the amount of silk fibroin solution (SFS), which may include silk-based proteins or fragments thereof, that may be fixed or otherwise adhered to the leather or leather article being coated. The wet pick up may be expressed by the following formula:

The total amount of SFS added to the leather or leather article may be expressed by the following formula:

In one embodiment, silk-based protein films are naturally derived, renewable and biodegradable. Without wishing to be bound by any particular theory, it is believed that expanding applications of silk-based biomaterials can potentially replace synthetic chemicals and promote sustainability and safety for commercial products. In most cases, silk crystallizes and forms rigid structure that has high young modulus and low elongation at break. This mainly due to inter-chain hydrogen bonding and hydrophobic interactions. This tight and crystalline structure can be disrupted and concerted into amorphous structure, a structure that is believed to make protein soft and flexible. In one embodiment, converting brittle/rigid films into flexible films is by adding plasticizer such as glycerol. Glycerol can interfere with inter-chain non-covalent bonding; thus, it creates space between protein chains and reduces “chain friction”. However, this technique has limitations. Adding excess amount of glycerol may “over plasticize” protein and difficult to form films; adding right amount of glycerol can only improve stretchability from 4% to 40%, which is still lower than commercial stretchy leather finishing topcoat resins whose elongation is over 500%. In one embodiment, the disruption of silk fibroin interactions can occur by adding salts. Salts are strongly charged and highly soluble in water, allowing them to strongly interact with protein segment. Specifically, anions can interact with positively charged NH3+ while cations can interact with -COO-. This strong electrostatic attraction may prevent proteins from forming beta-sheet, a crystalline structure responsible for its brittleness. In some embodiments, the incorporation of salts can improve silk film flexibility. Regarding methods for applying SFS to leather or leather articles more broadly, SFS may be applied to leather or leather articles through a pad or roller application on process, a saturation and removal process, and/or a topical application process. Moreover, the methods of silk application (i.e., SFS application or coating) may include bath coating, kiss rolling, spray coating, and/or two-sided rolling. In some embodiments, the coating processes (e.g., bath coating, kiss rolling, spray coating, two-sided rolling, roller application, saturation and removal application, and/or topical application), drying processes, and curing processes may be varied as described herein to modify one or more selected leather or leather article properties of the resulting coated leather or leather article wherein such properties. In an embodiment, the drying and/or curing temperature for the processes of the disclosure may be less than about 70 °C, or less than about 75 °C, or less than about 80 °C, or less than about 85 °C, or less than about 90 °C, or less than about 95 °C, or less than about 100 °C, or less than about 110 °C, or less than about 120 °C, or less than about 130 °C, or less than about 140 °C, or less than about 150 °C, or less than about 160 °C, or less than about 170 °C, or less than about 180 °C, or less than about 190 °C, or less than about 200 °C, or less than about 210 °C, or less than about 220 °C, or less than about 230 °C. In an embodiment, the drying and/or curing temperature for the processes of the disclosure may be greater than about 70 °C, or greater than about 75 °C, or greater than about 80 °C, or greater than about 85 °C, or greater than about 90 °C, or greater than about 95 °C, or greater than about 100 °C, or greater than about 110 °C, or greater than about 120 °C, or greater than about 130 °C, or greater than about 140 °C, or greater than about 150 °C, or greater than about 160 °C, or greater than about 170 °C, or greater than about 180 °C, or greater than about 190 °C, or greater than about 200 °C, or greater than about 210 °C, or greater than about 220 °C, or greater than about 230 °C. In an embodiment, the drying time for the processes of the disclosure may be less than about 10 seconds, or less than about 20 seconds, or less than about 30 seconds, or less than about 40 seconds, or less than about 50 seconds, or less than about 60 seconds, or less than about 2 minutes, or less than about, 3 minutes, or less than about 4 minutes, or less than about 5 minutes, or less than about 6 minutes, or less than about 7 minutes, or less than about 8 minutes, or less than about 9 minutes, or less than about 10 minutes, or less than about 20 minutes, or less than about 30 minutes, or less than about 40 minutes, or less than about 50 minutes, or less than about 60 minutes. In an embodiment, the drying time for the processes of the disclosure may be greater than about 10 seconds, or greater than about 20 seconds, or greater than about 30 seconds, or greater than about 40 seconds, or greater than about 50 seconds, or greater than about 60 seconds, or greater than about 2 minutes, or greater than about, 3 minutes, or greater than about 4 minutes, or greater than about 5 minutes, or greater than about 6 minutes, or greater than about 7 minutes, or greater than about 8 minutes, or greater than about 9 minutes, or greater than about 10 minutes, or greater than about 20 minutes, or greater than about 30 minutes, or greater than about 40 minutes, or greater than about 50 minutes, or greater than about 60 minutes. In an embodiment, the curing time for the processes of the disclosure may be less than about 1 second to less than about 60 minutes. In an embodiment, the curing time for the processes of the disclosure may be greater than about 1 second to greater than about 60 minutes. In some embodiments, a silk fibroin processed or coated material may be heat resistant to a selected temperature where the selected temperature is chosen for drying, curing, and/or heat setting a dye that may be applied to the material (e.g., a coated leather or leather article). As used herein, a “heat resistant” may refer to a property of the silk fibroin coating deposited on the material where the silk fibroin coating and/or silk fibroin protein does not exhibit a substantial modification (i.e., “substantially modifying”) in silk fibroin coating performance as compared to a control material having a comparable silk fibroin coating that was not subjected to the selected temperature for drying, curing, wash cycling, and/or heat setting purposes. In some embodiments, the selected temperature is the glass transition temperature (Tg) for the material upon which the silk fibroin coating is applied. In some embodiments, the selected temperature is greater than about 65 °C, or greater than about 70 °C, or greater than about 80 °C, or greater than about 90 °C, or greater than about 100 °C, or greater than about 110 °C, or greater than about 120 °C, or greater than about 130 °C, or greater than about 140 °C, or greater than about 150 °C, or greater than about 160 °C, or greater than about 170 °C, or greater than about 180 °C, or greater than about 190 °C, or greater than about 200 °C, or greater than about 210 °C, or greater than about 220 °C. In some embodiments, the selected temperature is less than about 65 °C, or less than about 70 °C, or less than about 80 °C, or less than about 90 °C, or less than about 100 °C, or less than about 110 °C, or less than about 120 °C, or less than about 130 °C, or less than about 140 °C, or less than about 150 °C, or less than about 160 °C, or less than about 170 °C, or less than about 180 °C, or less than about 190 °C, or less than about 200 °C, or less than about 210 °C, or less than about 220 °C. In some embodiments, the SFS processed, coated, or repaired article may be subjected to heat setting in order to set one or more dyes that may be applied to the SFS coated article in order to permanently set the one or more dyes on the SFS coated or repaired article. In some embodiments, the SFS processed, coated, or repaired article may be heat setting resistant, wherein the SFS coating on the SFS coated article may resist a heat setting temperature of greater than about 100 °C, or greater than about 110 °C, or greater than about 120 °C, or greater than about 130 °C, or greater than about 140 °C, or greater than about 150 °C, or greater than about 160 °C, or greater than about 170 °C, or greater than about 180 °C, or greater than about 190 °C, or greater than about 200 °C, or greater than about 210 °C, or greater than about 220 °C. In some embodiments, the selected temperature is less than about 100 °C, or less than about 110 °C, or less than about 120 °C, or less than about 130 °C, or less than about 140 °C, or less than about 150 °C, or less than about 160 °C, or less than about 170 °C, or less than about 180 °C, or less than about 190 °C, or less than about 200 °C, or less than about 210 °C, or less than about 220 °C. In an embodiment, a material processed, coated, or repaired by the silk fibroin coating or filling composition as described herein may partially dissolved or otherwise partially incorporated within a portion of the material after the silk fibroin coated or repaired material is subjected to heating and/or curing as described herein. Without being limited to any one theory, where the silk fibroin processed, coated, or repaired material is heated to greater than about the glass transition temperature (Tg) for the material that is processed, coated, or repaired, the silk fibroin coating may become partially dissolved or otherwise partially incorporated within a portion of the material. In some embodiments, a material processed, coated, or repaired by the silk fibroin coating as described herein may be sterile or may be sterilized to provide a sterilized silk fibroin coated material. Alternatively, or in addition thereto, the methods described herein may include a sterile SFS prepared from sterile silk fibroin. In some embodiments, SFS may be used in an SFS processing composition, coating, or repairing composition, where such composition or coating includes one or more chemical agents (e.g., a silicone). SFS may be provided in such an SFS coating at a concentration by weight (% w/w or % w/v) or by volume (v/v) of less than about 50%, or less than about 45%, or less than about 40%, or less than about 35%, or less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 9%, or less than about 8%, or less than about 7%, or less than about 6%, or less than about 5%, or less than about 4%, or less than about 3%, or less than about 2%, or less than about 1%, or less than about 0.9%, or less than about 0.8%, or less than about 0.7%, or less than about 0.6%, or less than about 0.5%, or less than about 0.4%, or less than about 0.3%, or less than about 0.2%, or less than about 0.1%, or less than about 0.01%, or less than about 0.001%. In some embodiments, SFS may be provided in such an SFS coating at a concentration by weight (% w/w or % w/v) or by volume (v/v) of greater than about 25%, or greater than about 20%, or greater than about 15%, or greater than about 10%, or greater than about 9%, or greater than about 8% , or greater than about 7%, or greater than about 6%, or greater than about 5%, or greater than about 4%, or greater than about 3%, or greater than about 2%, or greater than about 1%, or greater than about 0.9%, or greater than about 0.8%, or greater than about 0.7%, or greater than about 0.6%, or greater than about 0.5%, or greater than about 0.4%, or greater than about 0.3%, or greater than about 0.2%, or greater than about 0.1%, or greater than about 0.01%, or greater than about 0.001%. In some embodiments, chemical fabric softeners may include silicones as described herein. In some embodiments, the chemical agents may include the following, which are supplied by CHT Bezema and are associated with certain selected leather’s or leather article’s properties, which may be used to strengthen SFS binding on coated or repaired surfaces and/or SFS may be used for enhancing the following chemical agents’ properties:

TU TU TU TU TU TU

T T T T T

In some embodiments, the chemical agents of the disclosure may include the following, which are supplied by Lamberti SPA and are associated with certain selected leather or leather article properties, which may be used to strengthen SFS binding on coated or repaired surfaces or SFS may be used for enhancing such chemical agent properties: Pre treatment: Waterborne Polyurethanes Dispersions Rolflex AFP. Aliphatic polyether polyurethane dispersion in water. The product has high hydrolysis resistance, good breaking load resistance and excellent tear resistance. Rolflex ACF. Aliphatic polycarbonate polyurethane dispersion in water. The product shows good PU and PVC bonding properties, excellent abrasion resistance as well as chemical resistance, included alcohol. Rolflex V 13. Aliphatic polyether/acrylic copolymer polyurethane dispersion in water. The product has good thermoadhesive properties and good adhesion properties on PVC. Rolflex K 80. Aliphatic polyether/acrylic copolymer polyurethane dispersion in water. ROLFLEX K 80 is specifically designed as a high performing adhesive for textile lamination. The product has excellent perchloroethylene and water fastness. Rolflex ABC. Aliphatic polyether polyurethane dispersion in water. Particularly, the product presents very high water column, excellent electrolytes resistance, high LOI index, high resistance to multiple bending. Rolflex ADH. Aliphatic polyether polyurethane dispersion in water. The product has a very high water column resistance. Rolflex W4. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear where a full, soft and non sticky touch is required. Rolflex ZB7. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has a very high charge digestion properties, electrolites stability and excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex BZ 78. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has an excellent hydrolysis resistance, a very high charge digestion and electrolites stability and an excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex PU 147. Aliphatic polyether polyurethane dispersion in water. This product shows good film forming properties at room temperature. It has high fastness to light and ultraviolet radiation and good resistance to water, solvent and chemical agents, as well as mechanical resistance. Rolflex SG. Aliphatic polyether polyurethane dispersion in water. Due to its thermoplastic properties it is suggested to formulate heat activated adhesives at low temperatures. Elafix PV 4. Aliphatic blocked isocyanate Nano-dispersion used in order to give antifelting and antipilling properties to pure wool fabrics and his blend. Rolflex C 86. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where medium-soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Rolflex CN 29. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Oil and water repellents Lamgard FT 60. General purpose fluorocarbon resin for water and oil repellency; by padding application. Lamgard 48. High performance fluorocarbon resin for water and oil repellency; by padding application. High rubbing fastness. Imbitex NRW3 Wetting agent for water-and oil repellent finishing. Lamgard EXT. Crosslinker for fluorocarbon resins to improve washing fastness. Flame retardants Piroflam 712. Non-permanent flame retardant compound for padding and spray application. Piroflam ECO. Alogen free flame retardant compound for back coating application for all kind of fibers. Piroflam UBC. Flame retardant compound for back coating application for all kind of fibers. Crosslinkers Rolflex BK8. Aromatic blocked polyisocyanate in water dispersion. It is suggested as a cross-linking agent in coating pastes based of polyurethane resins to improve washing fastness. Fissativo 05. Water dispersible aliphatic polyisocyanate suitable as crosslinking agent for acrylic and polyurethane dispersions to improve adhesion and wet and dry scrub resistance. Resina MEL. Melamine-formaldehyde resin. Cellofix VLF. Low formaldehyde melamine resin. Thickeners Lambicol CL 60. Fully neutralized synthetic thickener for pigment printing in oil/water emulsion; medium viscosity type Viscolam PU conc. Nonionic polyurethane based thickener with pseudoplastic behavior Viscolam 115 new. Acrylic thickener not neutralized Viscolam PS 202. Nonionic polyurethane based thickener with newtonian behavior Viscolam 1022. Nonionic polyurethane based thickener with moderate pseudoplastic behavior. Dyeing Dispersing agents Lamegal BO. Liquid dispersing agent non ionic, suitable for direct, reactive, disperse dyeing and PES stripping Lamegal DSP. Dispersing / anti back-staining agent in preparation, dyeing and soaping of dyed and printed materials. Antioligomer agent. Lamegal 619. Effective low foam dispersing leveling agent for dyeing of PES Lamegal TL5. Multi-purpose sequestring and dispersing agent for all kind of textile process Levelling agents Lamegal A 12. Leveling agent for dyeing on wool, polyamide and its blends with acid or metalcomplex dyes Fixing agents Lamfix L. Fixing agent for direct and reactive dyestuffs, containing formaldheyde Lamfix LU conc. Formaldehyde free cationic fixing agent for direct and reactive dyes. It does not affect the shade and light fastness. Lamfix PA/TR. Fixing agent to improve the wet fastness of acid dyes on polyamide fabrics, dyed or printed and polyamide yarns. Retarding agent in dyeing of Polyamide/cellulosic blends with direct dyes. Special resins Denifast TC. Special resin for cationization of cellulose fibers to obtain special effects ("DENIFAST system" and "DENISOL system"). Cobral DD/50. Special resin for cationization of cellulose fibers to obtain special effect ("DENIFAST system" and "DENISOL system"). Antireducing agents Lamberti Redox L2S gra. Anti-reducing agent in grain form.100% active content Lamberti Redox L2S liq. Anti-reducing agent in liquid form for automatic dosage. Anticreasing agent Lubisol AM. Lubricating and anti creasing agent for rope wet operation on all kind of fibers and machines. Pigment dye Antimigrating agent Neopat Compound 96/m conc. Compound, developed as migration inhibitor for continuous dyeing process with pigments (pad-dry process). Binding agent Neopat Binder PM/S conc. Concentrated version of a specific binder used to prepare pad-liquor for dyeing with pigments (pad-dry process). All in One agent Neopat Compound PK1. High concentrated compound specifically developed as migration inhibitor with specific binder for continuous dyeing process with pigments (pad-dry process)all in one Delavè agent Neopat compound FTN. High concentrated compound of surfactants and polymers specifically developed for pigment dyeing and pigment-reactive dyeing process; especially for medium/dark shades for wash off effect Traditional finishing agents Wrinkle free treatment Cellofix ULF conc. Anti-crease modified glyoxalic resin for finishing of cottons, cellulosics and blend with synthetics fibers. Poliflex PO 40. Polyethilenic resin for waxy, full and slippy handle by foulard applications. Rolflex WF. Aliphatic waterborned Nano-PU dispersion used as extender for wrinkle free treatments. Softeners Texamina C/FPN. Cationic softening agent with a very soft handle particularly recommended for application by exhaustion for all kind of fabrics. Suitable also for cone application. Texamina C SAL flakes. 100% cationic softening agent in flakes form for all type of fabrics. Dispersible at room temperature. Texamina CL LIQ. Anphoteric softening agent for all types of fabrics. Not yellowing. Texamina HVO. Anphoteric softening agent for woven and knitted fabrics of cotton, other cellulosics and blends. Gives a soft, smooth and dry handle. Applied by padding. Texamina SIL. Nonionic silicon dispersion in water. Excellent softening, lubricating and anti-static properties for all fibre types by padding. Texamina SILK. Special cationic softener with silk protein inside. Gives a “swollen touch” particularly suitable for cellulosic, wool, silk. Lamfinish LW. All-in compound based on special polymeric hydrophilic softeners; by coating, foulard, and exhaustion. Elastolam E50. General purpose mono-component silicone elastomeric softener for textile finishing. Elastolam EC 100. Modified polysiloxane micro-emulsion which gives a permanent finishing, with extremely soft and silky handle. Handle modifier Poliflex CSW. Cationic anti-slipping agent. Poliflex R 75. Parafine finishing agent to give waxy handle. Poliflex s. Compound specifically developed for special writing effects. Poliflex m. Compound for special dry-waxy handle. Lamsoft SW 24. Compound for special slippy handle specifically developed for coating application. Lamfinish SLIPPY. All-in compound to get a slippy touch; by coating. Lamfinish GUMMY. All-in compound to get a gummy touch; by coating. Lamfinish OLDRY. All-in compound to get dry-sandy touch especially suitable for vintage effects; by coating Waterborne Polyurethanes Dispersions Rolflex LB 2. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings where bright and rigid top finish is required. It is particularly suitable as a finishing agent for organza touch on silk fabrics. Transparent and shiny. Rolflex HP 51. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for outwear, luggage, technical articles especially where hard and flexible touch is required. Transparent and shiny. Rolflex PU 879. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for outwear, luggage, technical articles where a medium-hard and flexible touch is required. Rolflex ALM. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for outwear, luggage, technical articles where a soft and flexible touch is required. Can be also suitable for printing application. Rolflex AP. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for outwear, fashion where a soft and gummy touch is required. Rolflex W4. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear where a full, soft and non sticky touch is required. Rolflex ZB7. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has a very high charge digestion properties, electrolites stability and excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex BZ 78. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has an excellent hydrolysis resistance, a very high charge digestion and electrolites stability and an excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex K 110. Gives to the coated fabric a full, soft, and slightly sticky handle with excellent fastness on all types of fabrics. Rolflex OP 80. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for outwear, luggage and fashion finishes where an opaque non writing effect is desired. Rolflex NBC. Aliphatic waterborned PU dispersion generally used by padding application as a filling and zero formaldheyde sizing agent. Can be used for outwear and fashion finishings where a full, elastic and non sticky touch is required. Rolflex PAD. Aliphatic waterborned PU dispersion specifically designed for padding application for outwear, sportswear and fashion applications where a full, elastic and non sticky touch is required. Excellent washing and dry cleaning fastness as well as good bath stability. Rolflex PN. Aliphatic waterborned PU dispersion generally applied by padding application for outerwear and fashion high quality applications where strong, elastic non sticky finishes are required. Elafix PV 4. Aliphatic blocked isocyanate Nano-dispersion used in order to give antifelting and antipilling properties to pure wool fabrics and his blend. Rolflex SW3. Aliphatic waterborned PU dispersion particularly suggested to be used by padding application for the finishing of outwear, sportswear and fashion where a slippery and elastic touch is required. It is also a good antipilling agent. Excellent in wool application. Rolflex C 86. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where medium-soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Rolflex CN 29. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Other resins Textol 110. Handle modifier with very soft handle for coating finishes Textol RGD. Water emulsion of acrylic copolymer for textile coating, with very rigid handle. Textol SB 21. Butadienic resin for finishing and binder for textile printing Appretto PV/CC. Vinylacetate water dispersion for rigid stiffening Amisolo B. CMS water dispersion for textile finishing as stiffening agent Lamovil RP. PVOH stabilized solution as stiffening agent Technical finishing agents Waterborne Polyurethanes Dispersions Rolflex AFP. Aliphatic polyether polyurethane dispersion in water. The product has high hydrolysis resistance, good breaking load resistance and excellent tear resistance. Rolflex ACF. Aliphatic polycarbonate polyurethane dispersion in water. The product shows good PU and PVC bonding properties, excellent abrasion resistance as well as chemical resistance, included alcohol. Rolflex V 13. Aliphatic polyether/acrylic copolymer polyurethane dispersion in water. The product has good thermoadhesive properties and good adhesion properties on PVC. Rolflex K 80. Aliphatic polyether/acrylic copolymer polyurethane dispersion in water. ROLFLEX K 80 is specifically designed as a high performing adhesive for textile lamination. The product has excellent perchloroethylene and water fastness. Rolflex ABC. Aliphatic polyether polyurethane dispersion in water. Particularly, the product presents very high water column, excellent electrolytes resistance, high LOI index, high resistance to multiple bending. Rolflex ADH. Aliphatic polyether polyurethane dispersion in water. The product has a very high water column resistance. Rolflex W4. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear where a full, soft and non sticky touch is required. Rolflex ZB7. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has a very high charge digestion properties, electrolites stability and excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex BZ 78. Aliphatic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, sportswear, fashion and technical articles for industrial applications. The product has an excellent hydrolysis resistance, a very high charge digestion and electrolites stability and an excellent mechanical and tear resistance. Can be also suitable for foam coating and printing application. Rolflex PU 147. Aliphatic polyether polyurethane dispersion in water. This product shows good film forming properties at room temperature. It has high fastness to light and ultraviolet radiation and good resistance to water, solvent and chemical agents, as well as mechanical resistance. Rolflex SG. Aliphatic polyether polyurethane dispersion in water. Due to its thermoplastic properties it is suggested to formulate heat activated adhesives at low temperatures. Elafix PV 4. Aliphatic blocked isocyanate Nano-dispersion used in order to give antifelting and antipilling properties to pure wool fabrics and his blend. Rolflex C 86. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where medium-soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Rolflex CN 29. Aliphatic cationic waterborned PU dispersion particularly suggested for the formulation of textile coatings for clothing, outwear, fashion where soft and pleasant full touch is required. Fabrics treated with the product can be dyed with a selection of dyes, to get double-color effects of different intensity. Oil and water repellents Lamgard FT 60. General purpose fluorocarbon resin for water and oil repellency; by padding application. Lamgard 48. High performance fluorocarbon resin for water and oil repellency; by padding application. High rubbing fastness. Imbitex NRW3. Wetting agent for water-and oil repellent finishing. Lamgard EXT. Crosslinker for fluorocarbon resins to improve washing fastness. Flame retardants Piroflam 712. Non-permanent flame retardant compound for padding and spray application. Piroflam ECO. Alogen free flame retardant compound for back coating application for all kind of fibers. Piroflam UBC. Flame retardant compound for back coating application for all kind of fibers Crosslinkers Rolflex BK8. Aromatic blocked polyisocyanate in water dispersion. It is suggested as a cross-linking agent in coating pastes based of polyurethane resins to improve washing fastness. Fissativo 05. Water dispersible aliphatic polyisocyanate suitable as crosslinking agent for acrylic and polyurethane dispersions to improve adhesion and wet and dry scrub resistance. Resina MEL. Melammine-formaldheyde resin. Cellofix VLF. Low formaldheyde malammine resin. Thickeners Lambicol CL 60. Fully neutralized synthetic thickener for pigment printing in oil/water emulsion; medium viscosity type Viscolam PU conc. Nonionic polyurethane based thickener with pseudoplastic behavior Viscolam 115 new. Acrylic thickener not neutralized Viscolam PS 202. Nonionic polyurethane based thickener with newtonian behavior Viscolam 1022. Nonionic polyurethane based thickener with moderate pseudoplastic behavior. In some embodiments, the chemical agent may include one or more of a silicone, an acidic agent, a dyeing agent, a pigment dye, a traditional finishing agent, and a technical finishing agent. The dyeing agent may include one or more of a dispersing agent, a levelling agent, a fixing agent, a special resin, an antireducing agent, and an anticreasing agent. The pigment dye may include one or more of an antimigrating agent, a binding agent, an all in one agent, and a delave agent. The traditional finishing agent may include one or more of a wrinkle free treatment, a softener, a handle modifier, a waterborne polyurethanes dispersion, and other resins. The technical finishing agent may include one or more of a waterborne polyurethanes dispersion, an oil repellant, a water repellant, a crosslinker, and a thickener. In some embodiments, certain chemical agents of the disclosure may be provided by one or more of the following chemical suppliers: Adrasa, AcHitex Minerva, Akkim, Archroma, Asutex, Avocet dyes, BCC India, Bozzetto group, CHT, Clariant, Clearity, Dilube, Dystar, Eksoy, Erca group, Genkim, Giovannelli e Figli, Graf Chemie, Huntsman, KDN Bio, Lamberti, LJ Specialties, Marlateks, Montegauno, Protex, Pulcra Chemicals, Ran Chemicals, Fratelli Ricci, Ronkimya, Sarex, Setas, Silitex, Soko Chimica, Tanatex Chemicals, Union Specialties, Zaitex, Zetaesseti, and Z Schimmer. In some embodiments, the chemical agent may include an acidic agent. Accordingly, in some embodiments, SFS may include an acidic agent. In some embodiments, an acidic agent may be a Bronsted acid. In an embodiment, the acidic agent includes one or more of citric acid and acetic acid. In an embodiment, the acidic agent aids the deposition and coating of SPF mixtures (i.e., SFS coating) on the leather or leather article to be coated as compared to the absence of such acidic agent. In an embodiment, the acidic agent improves crystallization of the SPF mixtures at the textile to be coated. In an embodiment, the acidic agent is added at a concentration by weight (% w/w or % w/v) or by volume (v/v) of greater than about 0.001% , or greater than about 0.002%, or greater than about 0.003%, or greater than about 0.004%, or greater than about 0.005%, or greater than about 0.006%, or greater than about 0.007%, or greater than about 0.008%, or greater than about 0.009%, or greater than about 0.01%, or greater than about 0.02%, or greater than about 0.03%, or greater than about 0.04%, or greater than about 0.05%, or greater than about 0.06%, or greater than about 0.07%, or greater than about 0.08%, or greater than about 0.09%, or greater than about 0.1%, or greater than about 0.2%, or greater than about 0.3%, or greater than about 0.4%, or greater than about 0.5%, or greater than about 0.6%, or greater than about 0.7%, or greater than about 0.8%, or greater than about 0.9%, or greater than about 1.0% or greater than about 2.0%, or greater than about 3.0%, or greater than about 4.0%, or greater than about 5.0% . In an embodiment, the acidic agent is added at a concentration by weight (% w/w or % w/v) or by volume (v/v) of less than about 0.001%, or less than about 0.002%, or less than about 0.003%, or less than about 0.004% , or less than about 0.005%, or less than about 0.006%, or less than about 0.007%, or less than about 0.008%, or less than about 0.009%, or less than about 0.01%, or less than about 0.02%, or less than about 0.03%, or less than about 0.04%, or less than about 0.05%, or less than about 0.06%, or less than about 0.07%, or less than about 0.08%, or less than about 0.09%, or less than about 0.1%, or less than about 0.2%, or less than about 0.3%, or less than about 0.4%, or less than about 0.5%, or less than about 0.6%, or less than about 0.7%, or less than about 0.8%, or less than about 0.9%, or less than about 1.0% or less than about 2.0%, or less than about 3.0%, or less than about 4.0%, or less than about 5.0%. In some embodiments, SFS may have a pH of less than about 9, or less than about 8.5, or less than about 8, or less than about 7.5, or less than about 7, or less than about 6.5, or less than about 6, or less than about 5.5, or less than about 5, or less than about 4.5, or less than about 4, or greater than about 3.5, or greater than about 4, or greater than about 4.5, or greater than about 5, or greater than about 5.5, or greater than about 6, or greater than about 6.5, or greater than about 7, or greater than about 7.5, or greater than about 8, or greater than about 8.5. In some embodiments, SFS may include an acidic agent, and may have a pH of less than about 9, or less than about 8.5, or less than about 8, or less than about 7.5, or less than about 7, or less than about 6.5, or less than about 6, or less than about 5.5, or less than about 5, or less than about 4.5, or less than about 4, or greater than about 3.5, or greater than about 4, or greater than about 4.5, or greater than about 5, or greater than about 5.5, or greater than about 6, or greater than about 6.5, or greater than about 7, or greater than about 7.5, or greater than about 8, or greater than about 8.5. In an embodiment, the chemical agent may include silicone. In some embodiments, a SFS may include silicone. In some embodiments, the leather or leather article may be pretreated (i.e., prior to SFS application) or post-treated (i.e., after SFS application) with silicone. In some embodiments, silicone may include a silicone emulsion. The term “silicone,” may generally refer to a broad family of synthetic polymers, mixtures of polymers, and/or emulsions thereof, that have a repeating silicon-oxygen backbone including, but not limited to, polysiloxanes. In some embodiments, a silicone may include any silicone species disclosed herein. Describing the compositions and coatings more broadly, silicone may be used, for example to improve hand, but may also increase the water repellency (or reduce water transport properties) of a material coated with silicone. In some embodiments, SFS may include silicone in a concentration by weight (% w/w or % w/v) or by volume (v/v) of less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 9%, or less than about 8%, or less than about 7%, or less than about 6%, or less than about 5%, or less than about 4%, or less than about 3%, or less than about 2%, or less than about 1%, or less than about 0.9%, or less than about 0.8%, or less than about 0.7%, or less than about 0.6%, or less than about 0.5%, or less than about 0.4%, or less than about 0.3%, or less than about 0.2%, or less than about 0.1%, or less than about 0.01%, or less than about 0.001%. In some embodiments, SFS may include silicone in a concentration by weight (% w/w or % w/v) or by volume (v/v) of greater than about 25%, or greater than about 20%, or greater than about 15%, or greater than about 10%, or greater than about 9%, or greater than about 8% , or greater than about 7%, or greater than about 6%, or greater than about 5%, or greater than about 4%, or greater than about 3%, or greater than about 2%, or greater than about 1%, or greater than about 0.9%, or greater than about 0.8%, or greater than about 0.7%, or greater than about 0.6%, or greater than about 0.5%, or greater than about 0.4%, or greater than about 0.3%, or greater than about 0.2%, or greater than about 0.1%, or greater than about 0.01%, or greater than about 0.001%. In some embodiments, SFS may be supplied in a concentrated form suspended in water. In some embodiments, SFS may have a concentration by weight (% w/w or % w/v) or by volume (v/v) of less than about 50%, or less than about 45%, or less than about 40%, or less than about 35%, or less than about 30%, or less than about 25%, or less than about 20%, or less than about 15%, or less than about 10%, or less than about 5%, or less than about 4%, or less than about 3%, or less than about 2%, or less than about 1%, or less than about 0.1%, or less than about 0.01%, or less than about 0.001%, or less than about 0.0001%, or less than about 0.00001%. In some embodiments, SFS may have a concentration by weight (% w/w or % w/v) or by volume (v/v) of greater than about 50%, or greater than about 45%, or greater than about 40%, or greater than about 35%, or greater than about 30%, or greater than about 25%, or greater than about 20%, or greater than about 15%, or greater than about 10%, or greater than about 5%, or greater than about 4%, or greater than about 3%, or greater than about 2%, or greater than about 1%, or greater than about 0.1%, or greater than about 0.01%, or greater than about 0.001%, or greater than about 0.0001%, or greater than about 0.00001%. In some embodiments, an SFS coating may include SFS, as described herein. In some embodiments, SFS may include a silicone and/or an acidic agent. In some embodiments, SFS may include a silicone and an acidic agent. In some embodiments, the SFS may include a silicone, an acidic agent, and/or an additional chemical agent, wherein the additional chemical agent may be one or more of the chemical agents described herein. In some embodiments, SFS may include a silicone emulsion and an acidic agent, such as acetic acid or citric acid. In some embodiments, the coating processes of the disclosure may include a finishing step for the resulting coated materials. In some embodiments, the finishing or final finishing of the materials that are coated with SFS under the processes of the disclosure may include sueding, steaming, brushing, polishing, compacting, raising, tigering, shearing, heatsetting, waxing, air jet, calendaring, pressing, shrinking, treatment with polymerizer, coating, lamination, and/or laser etching. In some embodiments, finishing of the SFS coated materials may include treatment of the textiles with an AIRO® 24 dryer that may be used for continuous and open-width tumbling treatments of woven, non-woven, and knitted fabrics. Coating Performance Testing In embodiments, the coating system described herein passes a wet color fastness rubbing test up to 600 cycles, passes an adhesive tape test, and passes a Bally flex test up to 20,000 cycles with no delamination observed. Some non-limiting examples of performance tests are further described below. Veslic Test/ Color Fastness Rubbing Test Dry rubbing color fastness refers to the situation of fading and staining of dyed fabric when rubbed with piece of cloth, felt, or something similar. Wet rubbing color fastness refers to the situation of fading and staining of dyed fabric when rubbed with piece of cloth, felt, or something similar which water content is 95% to 105%. In embodiments, the coating system described herein passes a Dry CFR test up to 1,000 cycles with a score of 5. In other words, little or no fading on the leather or staining on the rubbing material was observed up to 1,000 cycles. In embodiments, the coating system described herein passes a dry CFR test up to 1,000 cycles with a grade 5, up to 1,000 cycles with a grade 4, up to 1,000 cycles with a grade 3, up to 1,000 cycles with a grade 2, or up to 1,000 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 900 cycles with a grade 5, up to 900 cycles with a grade 4, up to 900 cycles with a grade 3, up to 900 cycles with a grade 2, or up to 900 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 800 cycles with a grade 5, up to 800 cycles with a grade 4, up to 800 cycles with a grade 3, up to 800 cycles with a grade 2, or up to 800 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 700 cycles with a grade 5, up to 700 cycles with a grade 4, up to 700 cycles with a grade 3, up to 700 cycles with a grade 2, or up to 700 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 600 cycles with a grade 5, up to 600 cycles with a grade 4, up to 600 cycles with a grade 3, up to 600 cycles with a grade 2, or up to 600 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 500 cycles with a grade 5, up to 500 cycles with a grade 4, up to 500 cycles with a grade 3, up to 500 cycles with a grade 2, or up to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 400 cycles with a grade 5, up to 400 cycles with a grade 4, up to 400 cycles with a grade 3, up to 400 cycles with a grade 2, or up to 400 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 300 cycles with a grade 5, up to 300 cycles with a grade 4, up to 300 cycles with a grade 3, up to 300 cycles with a grade 2, or up to 300 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 200 cycles with a grade 5, up to 200 cycles with a grade 4, up to 200 cycles with a grade 3, up to 200 cycles with a grade 2, or up to 200 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test up to 100 cycles with a grade 5, up to 400 cycles with a grade 4, up to 100 cycles with a grade 3, up to 100 cycles with a grade 2, or up to 100 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 800 to 1000 cycles with a grade 5, from 800 to 1000 cycles with a grade 4, from 800 to 1000 cycles with a grade 3, from 800 to 1000 cycles with a grade 2, or from 800 to 1000 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 600 to 800 cycles with a grade 5, from 600 to 800 cycles with a grade 4, from 600 to 800 cycles with a grade 3, from 600 to 800 cycles with a grade 2, or from 600 to 800 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 500 to 600 cycles with a grade 5, from 500 to 600 cycles with a grade 4, from 500 to 600 cycles with a grade 3, from 500 to 600 cycles with a grade 2, or from 500 to 600 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 400 to 500 cycles with a grade 5, from 400 to 500 cycles with a grade 4, from 400 to 500 cycles with a grade 3, from 400 to 500 cycles with a grade 2, or from 400 to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 500 to 1000 cycles with a grade 5, from 500 to 1000 cycles with a grade 4, from 500 to 1000 cycles with a grade 3, from 500 to 1000 cycles with a grade 2, or from 500 to 1000 cycles with a grade 1. In embodiments, the coating system described herein passes a dry CFR test from 100 to 500 cycles with a grade 5, from 100 to 500 cycles with a grade 4, from 100 to 500 cycles with a grade 3, from 100 to 500 cycles with a grade 2, or from 100 to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 600 cycles with a grade 5, up to 600 cycles with a grade 4, up to 600 cycles with a grade 3, up to 600 cycles with a grade 2, or up to 600 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 600 cycles with a grade 5, up to 600 cycles with a grade 4, up to 600 cycles with a grade 3, up to 600 cycles with a grade 2, or up to 600 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 500 cycles with a grade 5, up to 500 cycles with a grade 4, up to 500 cycles with a grade 3, up to 500 cycles with a grade 2, or up to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 400 cycles with a grade 5, up to 400 cycles with a grade 4, up to 400 cycles with a grade 3, up to 400 cycles with a grade 2, or up to 400 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 300 cycles with a grade 5, up to 300 cycles with a grade 4, up to 300 cycles with a grade 3, up to 300 cycles with a grade 2, or up to 300 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test (also referred to as Wet Veslic Test) up to 200 cycles with a grade 5, up to 200 cycles with a grade 4, up to 200 cycles with a grade 3, up to 200 cycles with a grade 2, or up to 200 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 100 cycles with a grade 5, up to 100 cycles with a grade 4, up to 100 cycles with a grade 3, up to 100 cycles with a grade 2, or up to 100 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 50 cycles with a grade 5, up to 50 cycles with a grade 4, up to 50 cycles with a grade 3, up to 50 cycles with a grade 2, or up to 50 cycles with a grade 1. In embodiments, the coating system described herein passes a Wet CFR test up to 20 cycles with a grade 5, up to 20 cycles with a grade 4, up to 20 cycles with a grade 3, up to 20 cycles with a grade 2, or up to 20 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 100 to 500 cycles with a grade 5, from 100 to 500 cycles with a grade 4, from 100 to 500 cycles with a grade 3, from 100 to 500 cycles with a grade 2, or from 100 to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 500 to 600 cycles with a grade 5, from 500 to 600 cycles with a grade 4, from 500 to 600 cycles with a grade 3, from 500 to 600 cycles with a grade 2, or from 500 to 600 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 400 to 500 cycles with a grade 5, from 400 to 500 cycles with a grade 4, from 400 to 500 cycles with a grade 3, from 400 to 500 cycles with a grade 2, or from 400 to 500 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 200 to 400 cycles with a grade 5, from 200 to 400 cycles with a grade 4, from 200 to 400 cycles with a grade 3, from 200 to 400 cycles with a grade 2, or from 200 to 400 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 100 to 200 cycles with a grade 5, from 100 to 200 cycles with a grade 4, from 100 to 200 cycles with a grade 3, from 100 to 200 cycles with a grade 2, or from 100 to 200 cycles with a grade 1. In embodiments, the coating system described herein passes a wet CFR test from 10 to 100 cycles with a grade 5, from 10 to 100 cycles with a grade 4, from 10 to100 cycles with a grade 3, from 10 to 100 cycles with a grade 2, or from 10 to 100 cycles with a grade 1. Bally Flex Test A Bally Flex Test is conducted to determine leather flex resistance by flexing leather in a certain angle and speed. Samples are loaded into 12-Station Bally Flex Tester (Schap Specialty Machine) an subjected to cycles of flexing. In embodiments, the substrate and a coating system disclosed herein passes a Bally Flex test up to 1,000 cycles, up to 5,000 cycles, up to 10,000 cycles, up to 15,000 cycles, and up to 20,000 cycles with no delamination, in other words, there is no separation between the coating system and the substrate. In embodiments, the substrate and a coating system disclosed herein passes a Bally Flex test from 1,000 cycles to 5,000 cycles, from 5,000 cycles to 10,000 cycles, from 10,000 cycles to 15,000 cycles, or from 15,000 cycles to 20,000 cycles with no delamination. Adhesive Tape Test In an adhesive tape test, a piece of tape (i.e. Scotch Tape) is applied to leather, pressed firmly by hand, then ripped off and inspected to see if any particles come off of leather. If no particles are seen on the tape, it can be inferred there was no delamination or separation observed between the substrate and coating. In embodiments of the present disclosure, no delamination was observed using 4 g/sqft L5267 and 6 g/sqft of L0822. EXAMPLES The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the described embodiments, and are not intended to limit the scope of what the inventors regard as their invention nor are they intended to represent that the experiments below are all or the only experiments performed. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is weight average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric. Example 1: Colorfastness to Rubbing Colorfastness to rubbing (Wet Veslic Testing) is one of the most important and difficult technical specifications to achieve for leather finishing chemicals. Herein, it is shown silk fibroin fragment compositions described herein (Activated Silk, Entry B2) outperforms polyurethane systems specifically designed as top-coats (Stahl WT-13-097) with enhanced CFR performance (Stahl WT-42-518) at lower dry mass loadings deposited on the surface of the leather. Specifically, the silk fibroin fragments compositions are able to endure >600 rub cycles without any deterioration in the appearance or water repellency of the leather thereby stage for the complete replacement of polyurethanes in leather finishing. In terms of CFR requirements for various use cases, the luxury sector requires a minimum of 10 cycles, the furnishing market requires a minimum of 500 cycles and the automotive market requires 500-1000 cycles. The performance disclosed here demonstrates that the silk fibroin fragments (Entry B2) far exceeds the CFR requirements for luxury goods and is an early indicator for the use of the Activated Silk™ in use cases such as automotive leather and furnishing which demand greater performance (See Fig.4 Photograph of the felt pads (and associated leather samples) after 600 continuous cycles of Wet Veslic Rubbing, comparing silk fibroin fragment compositions (bottom sample – Entry B2) treated leather samples to polyurethane (top 2 samples) treated leather samples. Note the damage to the polyurethane samples and loss of dye from the leather to the felt after 600 cycles). Materials: AS™ Formulations: The evaluated formulation consists of 2 components deposited sequentially via spray coating on the surface of the leather sample: Component 1: silk fibroin fragment compositions (Activated Silk ™) with 0- 5% crosslinker in water. Component 2: Proprietary auxiliary delivered in ethanol. Polyurethane reference samples: PU1: Stahl WT-42-518 crosslinked with 5% Melio 09S11. Total solids content of Stahl WT-42-518 is 10%. PU2: Stahl WT-13-097 crosslinked with 5% Melio 09S11. Total solids content of Stahl WT-13-097 is 8.75%. Leather samples: Bodin Brown (Color 872) plongé leather samples were obtained from Bodin-Joyeux and were used as received. Procedures Coating Process Components 1 and 2: were sequentially delivered to the leather surface via spray coating. Spray applications were applied from a distance of 2 ft and at an outlet pressure of 60 psi. The wet mass loading for each layer was set to 3 g/ft² and measured directly after deposition. Samples were allowed to visually dry between deposition steps. PU1 and PU2: were delivered in a single pass using the same spray coating methodology as described herein. The target wet mass loading was 3 g/ft². Colorfastness to Wet Veslic Rubbing (ISO 11640): Testing was completed as described in EBN-SOP-TXTL-035. Samples were allowed to rest for 48 hours prior to testing. Results Initial screening results show a marked improvement in Colorfastness to Wet Veslic Rubbing (10 cycles) when using the silk fibroin fragments (Activated Silk ™). The data is summarized in Table 1 and in Figure 5. Reproducibility of the solution is highlighted in Table 2. Table 1 comprises the CFR results for multiple formulations. Figure 5: Photographs of the felt pads after 10 cycles of Wet Veslic Rubbing on silk fibroin fragments treated leather samples. Table 2: Reproducibility of silk fibroin fragments results for Colorfastness to Wet Veslic Rubbing (ISO 11640) (600 Cycles). Figure 5. Photographs of the felt pads after 10 cycles of Wet Veslic Rubbing on Entries A1, A2, B1 and B2 (from Table 1) treated leather samples. Table 1. Initial screening results for Colorfastness to Wet Veslic Rubbing (ISO 11640) E A A B B

P P

a Cellulose derivatives are methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, microcrystalline cellulose. b Plasticizers are triethyl citrate, dibutyl sebacate, triacetin, glycerol, 1,3-propanediol, propylene glycol, pentylene glycol, epoxidized vegetable oils, isosorbide esters, succinic acid derivatives, acetic acid ester of monoglycerides. c Crosslinkers are polyisocyanates, polycarbodiimides, polyaziridines, polyureas, glutaraldehyde, starch dialdehyde. Table 2. Reproducibility of silk fibroin fragment compositions (Activated Silk ™) results for Colorfastness to Wet Veslic Rubbing (ISO 11640) (600 Cycles) _E B B B B B B B

With these results in hand, the Colorfastness to Wet Veslic Rubbing was extended from 10 cycles to 600 cycles for the formulation described in Entry B2. The results of this experiment are shown in Figure 4. These experiments were repeated using standard crosslinked polyurethane coating systems for comparison (PU1 and PU2). Figure 4: comparison photographs of the felt pads and associated leather samples after 600 continuous cycles of Wet Veslic Rubbing. Top: commercial references (crosslinked polyurethanes PU1 and PU2); Bottom: silk fibroin fragments. Figure 4. Photograph of the felt pads (and associated leather samples) after 600 continuous cycles of Wet Veslic Rubbing, comparing silk fibroin fragment compositions (Activated Silk ™) (Entry B2) treated leather samples to PU1 and PU2 (commercial references) treated leather samples. The water repellency of silk fibroin fragments is qualitatively depicted in Figure 6. Figure 6 depicts the water repellency of silk fibroin fragments treated leather after 600 cycles of Wet Veslic Rubbing as compared to crosslinked polyurethanes PU1 and PU2 after 10 cycles. Figure 6. Photograph of water droplets placed on samples treated either with silk fibroin fragments or a crosslinked polyurethane coating system after Wet Veslic Rubbing has been performed. In the case of silk fibroin fragments (Entry B2), the sample was exposed to 600 cycles of rubbing whereas the polyurethane samples only endured 10 cycles. The photograph was taken 5 minutes after placing the water droplets. Note the penetration of water into the leather matrix when using the commercial reference systems designed as top- coats. Conclusions The results shown in Figures 4-7 and Tables 1-2 demonstrate a marked improvement in the wet CFR performance of silk fibroin fragments (Entry B2) deposited on Bodin Brown leather. The performance extends to at least 600 continuous cycles without deterioration in wet CFR performance and outperforms conventional crosslinked polyurethane systems. Silk fibroin fragments provide enhanced water repellency that endures after the abrasion encountered during the Wet Veslic Rubbing as shown in Figure 6. Example 2: Coating Aniline Leather In some embodiments, the leather coating may contain multiple layers, including an optional adhesive layer, and a topcoat layer. The optional adhesive layer may contain bio- derived polyurethane (e.g., Biopur 3015), optionally silk fibroin fragments compositions (e.g., AS-104 LS), and a solvent (e.g., water). The bio-derived polyurethane content may be from 20% to 21%, from 21% to 22%, from 22% to 23%, or from 23% to 24%. The silk fibroin fragments compositions content may be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. The topcoat layer may contain a cellulose derivative, alcohol solvents, and a glycerin derivative (e.g., Solketal (AUGEO SL 191)). In some embodiments, the cellulose derivative is selected from methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose. The cellulose derivative content may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. The glycerin derivative content may be from 5% to 6%, from 6% to 7%, from 7% to 8%, from 8% to 9%, from 9% to 10%, from 10% to 11%, from 11% to 12%, from 12% to 13%, from 13% to 14%, or from 14% to 15%. Suitable solvents include, but are not limited to methanol, ethanol, acetone, isopropanol, n-Butanol, or combination thereof. The topcoat layer may contain 40% to 41%, 41% to 42%, 42% to 43%, 43% to 44%, 44% to 45%, 45% to 46%, 46% to 47%, 47% to 48%, 48% to 49%, or 49% to 50% ethanol. The topcoat layer may contain 30% to 31%, 31% to 32%, 32% to 33%, 33% to 34%, 34% to 35%, 35% to 36%, 36% to 37%, 37% to 38%, 38% to 39%, or 39% to 40% n- Butanol. Without wishing to be bound by any particular theory, it is believed that a solvent used in any layer described herein, would provide maximum benefit during a coating application step and/or method, and would thereafter be largely removed during a drying step and/or method. The application rate on the solids for the various layers may be from about 0.25 to about 1.5 g/ft², e.g., and without limitation, about 0.728 g/ft² for the optional adhesive layer, and from about 0.015 to about 0.15 g/ft², e.g., and without limitation, about 0.05 g/ft² for the topcoat layer. Table 3 below shows a non-limiting example of the topcoat and adhesive layer components. Table 3. Adhesive and Topcoat Layers’ components. Adhesive Layer Biopur 3015: 22.5% Activated Silk (AS) 1 LS: 0.5% (optional) Solvent (water)

Example 3: Activated Silk on Nubuck Leather PURPOSE/SCOPE OF THE STUDY The main purpose of this study was to evaluate the potential of silk fibroin fragments compositions (e.g., 117-AS) as dye fixing agent for leather. The idea was to compare classical fixing agents used in leather dyeing with silk fibroin fragments compositions and evaluate comparative performance as well as effect on leather (color & feel). The fixing agent that was used as reference is OPTIFIX E-50 liq, an aliphatic polyamine. SUBSTRATE USED/ PREPARATIONS Nubuck leather was used as a substrate dyed with a leather dye with poor rubbing fastness, DORAN IL ORANGE BROWN S3R, to be able to see the effect of fixing agents in fastness improvement. Nubuck was dyed with an offer of 4% plus 2% in top after acidification (on shaved weight).OPTIFIX ES0 was used as a fixing agent this fixing agent is normally used in the wet-end stage, and it was applied as such at a temperature of 40 °C: • 300% Water • 0.2% Formic acid • Run 10' • 2% Optifix ES0 • Run 20' • 0.4% Formic acid • Drain and wash • Dry to crust The activated silk was applied in the finishing stage, through spraying. Crosslinking of the activated silk was done through two different systems: a. with CARTARETIN F liq. an aqueous solution of polyamidamine used in paper industry, and that has shown very good results as crosslinker of bio-based acrylics. b. with MELIO 09-S-ll (Stahl) Table 4. Preparations done.

Additional notes: Optifix E-50 liq was applied in separate bath, at pH 3.8-4.0, running 30 min. Amounts in refs.2 to 7 are parts per 100. All of them applied by spraying, two crosses. RESULTS Pieces treated with different systems were allowed to cure during 24 hand brought to rubbing test, ISO 105-Xl2. A summary of the results was collected in the table below: Table 5. Results: change in color, feel & fastness R

Notes: All valuations are in scale of 1 to 5, meaning: change in color / touch: 5 minimum effect /change rubbing fastness: 5 maximum resistance = minimum staining CONCLUSIONS Dry rubbing fastness improvement with 117-AS was remarkable, in both systems. Wet rubbing fastness improvement was considerably lower, even nothing in the case of Isocyanate. The best scores were achieved with a moderate amount of 117-AS in the formulation (around 17%). The finishing spray always gives a filming effect not helping in nubuck leather. Example 4: Silk Solutions Used for Treating Leather A number of silk solutions are prepared for the treatment of leather, as described in Table 6, and maybe used as described herein. Table 6. Silk formulations for different stages of leather treatment. Ty Sil 6% (L 6% (L 6% (L

6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L 6% (L

6% (L 6% (L 6% (L 6% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 1% (L 6% 13 6% 12 6% 11 6% 10 6% 9 6% 8 6% 7

6% pH 6% pH 6% pH 6% 3 6% pH 1% pH 1% pH 1% pH 1% pH 1% pH 1% 6 1% 5 1% 4 1% 3 1% 2

Silk formulations as described herein may be used before, during, or after various leather processing steps, including: Drying – Drying of hand and autosprayed skins may be done in production line ovens used during normal leather processing. The autosprayed skins may be dried one or more times in between one or more spray treatments, e.g., spray > dry > spray > dry. Oven temperature may vary between 70-75 °C and each dry round may last ~25 seconds. Stamping – Stamping may be used during the production process of leathers. During the process, a skin is compressed (treated side up) between two metal plates (approx.5-6 m²), the top plate operating at 57 °C. The skin is compressed at this temperature for 2 seconds at 100 kg/cm². Qualitatively speaking, the stamping process may add sheen to the leather sample. Finiflex – A typical processing step for plongé leathers, this mechanical treatment may be used as a final step for silk-doped leathers. The skin is processed in two halves on this machine – the skin half is lifted into and compressed by a rotating heated metallic wheel (93 °C; 20 kg/m²; d_wheel = 0.3 m) for 4 seconds. The skin is then pulled out, flipped, and the other half is treated in the same way. Uniflex – The Uniflex treatment is similar to the Finiflex treatment, used at the final stage of leather processing. During this process, a skin is fed onto a feeder belt into two pressing cylinders (each 0.3 m in diameter). The top cylinder is heated to 60 °C, while the bottom cylinder is unheated. Together, the cylinders compress the skin at 30 bar for 3-5 seconds. Polishing – The polisher shaves off some of the surface treatment(s) done on the leather in prior processing steps (physical abrasion). At earlier stages in leather processing this serves to “open up” the skin for more effective adhesion of fixation / pigmentation agents in a similar way to the mechanical stretching process which occurs right before trimming of the skins. Autosprayer – Unless otherwise noted, when skins are sprayed using the in-house automatic spray machine they may be sprayed in one or more rounds with intermediate drying treatments. Spraying fluid (silk, silicone treatment, etc.) may be pumped into the nozzle feed lines at 3 bar, and fed into the nozzle inlet (Dnozzle = 0.6 mm) at a pressure between 0.8 – 1.2 bar. The spray volume of the AUTO sprayer may vary between 0.8 – 1.0 g/ft². The residence volume of the spraying fluid may be approximately 2 – 2.5 L. Various silk formulations described herein may be able to be fed into such machine and sprayed evenly onto skins. The hand spray process may involve one or more coats, e.g., two passes each of different orientation, coat 1 vertically oriented spray pattern, and coat 2 horizontally-oriented spray pattern, of silk deposited onto half of one skin, with the other half covered up as a control. Hand-spray coating volumes may be approximately 50 mL per coat. 6% coated skins may have a noticeably darker sheen when placed under viewing light, and may be slightly stiffer to the touch compared to the untreated control half. Example 5: Formulation Preparation Materials: Selected salts include calcium chloride (CaCl2), sodium chloride (NaCl), magnesium sulfate heptahydrate (MgSO₄), guanidine hydrochloride (GdmCl), L-Arginine hydrochloride (ArgCl), urea, magnesium chloride (MgCl2), calcium lactobionate (CaLact), ammonium sulfate {(NH₄)₂SO₄} and calcium sulfate dihydrate (CaSO₄). Plasticizer. Glycerol is used as plasticizer. AS-104 (6%) low molecular weight (14-30 kDa) is used as main components for film formation. Prepare 20 mL of 1 M salts stock solution based on Table 7. Weight proper amount of solid salt and dissolve in 20 mL deionized water. After dissolving, using stirring plate to stir for 10 minutes. Then keep salts solution in fridge. Calcium lactobionate concentration is reduced to 0.5 M due to solubility limitation. Table 7. Salt Stock Solution Preparation. M

Prepared salts solution was stirred at room temperature for 10 minutes. Salts solutions are kept in fridge before use. Weight 15 g of AS-104 silk solution, then mix it with 0.3 g glycerol. Place AS-104 + glycerol mixture onto stirring plate and stir for 30 minutes. Then add 75, 150, 375 and 750 uL salt stock solutions into AS-104-Glycerol mixtures to make salts concentration as 5, 10, 25 and 50 mM. Continue to stir the mixture for 1 hour. Keep the stir bar rpm lower enough to avoid foaming. After 1 hour stirring, move mixture to vacuum and de-gas for 1 hour. Thoroughly clean a silicone mold (3-in diameter), pre-wet silicone mold with deionized water and then cast around 10 g of prepared mixture onto silicone mold. Record mass of both silicone mold-alone and silicone mold + liquid mixture. Ensure liquid spreads and cover the entire bottom of silicone mold. Place silicone mold in incubator at 35 Celsius and 40% relative humidity. Dry the mixture for 12 hours. Example 6: Testing Method Instron Tensile Testing: After 12 hours, bend the edge of silicone mold and peel off films. Trim films edge out and keep the middle part of films. Cut three 15 by 45 mm testing area. Measure and record film thickness before tensile testing. Trace out 10 mm on both ends of cut films. Use grinding paper to clap 10 mm and place sample on Instron Tester and set strain rate as 5 mm/minute. Shore A Hardness of Thin Films and Veslic testing was performed. Example 7: Results Summary Table 8. Elongation and Tensile Strength of AS-104-based Films Assisted by Various Salts and concentrations.

Table 9. Shore A Hardness of AS-104-based Films Assisted by Various Salts and concentrations. Formula 6% AS^TM 6% AS^TM 6% AS^TM 6% AS^TM 6% AS^TM 6% AS^TM 6% AS^TM MgSO4 6% AS^TM 6% AS^TM 6% AS^TM 6% AS^TM

Example 8: Combination Formulations Table 10: Combination Formulations T

Re ^Pla

Example 9: Water Vapor Transmission Test (WVT) of Leather Test Used: ASTM Standard E96/E96M-21, "Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials," (Modified), ASTM International, West Conshohocken, PA, 2016, astm.org. The purpose of these tests is to obtain, by means of simple apparatus, reliable values for water vapor transfer rate through materials, expressed in suitable units. These test methods cover the determination of water vapor transmission rate (WVTR) of materials, such as, but not limited to, paper, plastic films, other sheet materials, coatings, foams, fiberboards, gypsum and plaster products, wood products, and plastics. Testing Information: • Procedure B (water method) used • Test Temperature: 23.00 °C • Relative Humidity: 50.00 % • The Face of fabric was exposed to Water the back of the fabric was exposed to Air • Test Equipment: TEXTEST FX 3180 Cupmaster with aluminum cups, sealed with NBR and Teflon gaskets, and twist-down clamp ring • A higher MVTR value indicates there is a greater passage of moisture vapor through the material Results: Water Vapor Transmission Test on Leather with Coating System #1: Results from this test are illustrated in FIG.7A and Table 12a below. Table 12a: WVT Testing Results on Coated Leather Test #1

Water Vapor Transmission Test on Leather Crust (no coating) #1: Results from this test are illustrated in FIG.7B and Table 12b below. Table 12b: WVT Testing Results on Uncoated Leather Test #1

Water Vapor Transmission on Leather with Coating System Test on Leather with Coating System #2: Results from this test are illustrated in FIG.8A and Table 13a below. Table 13a: WVT Testing Results on Coated Leather Test #2

Water Vapor Transmission Test on Leather Crust (no coating) #2: Results from this test are illustrated in FIG.8B and Table 12b below. Table 12b: WVT Testing Results on Uncoated Leather Test #2

Water Vapor Transmission Test on Leather with Coating System #3: Results from this test are illustrated in FIG.9A and Table 13a below. Table 13a: WVT Testing on Coated Leather Results Test #3

Water Vapor Transmission Test on Leather Crust (no coating) #3: Results from this test are illustrated in FIG.9B and Table 13b below. Table 13b: WVT Testing Results on Uncoated Leather Test #3

These results show that the coated leather allowed the passage of water vapor. This illustrates the breathability of the leather coating, while still providing waterproofing properties. Water droplets were unable to pass, but water vapor was able to pass through the specimen. Example 10: Oil Repellency Test on Leather Test Method: AATCC TM118-2020, Test Method for Oil Repellency: Hydrocarbon Resistance Test Testing Information: • Specimen size: 8"x8" • The scale ranges from zero to eight, with a rating of eight signifying the most repellent surface. • Sample brought to moisture equilibrium; Testing Conditions: 21°C (± 2°C) and 65%RH (± 5%RH) Table 14a: Results from Oil Repellency Test on Leather with Coating System

Table 14b: Results from Oil Repellency Test on Leather Crust (no coating)

The results shown in Tables 14a- 14b show that coated leather, graded with a 6 out of 8, exhibited far better oil repellency over uncoated leather, graded a 0 out of 8. Example 11: Soil Release Test on Leather Test Method for Soil Release: Oily Stain Release - AATCC TM130-2018t – Modified Testing Information: • Modification = Stains used: o French's® 100% Natural Classic Yellow® Mustard o 100% Natural Hunt's® Tomato Ketchup® o Distilled Water o Wine Cube® Merlot California o Top Soil - 25% Top Soil o Mazola Corn Oil o Stars and Stripes Cola o French's® Dressing o Artificial Urine • A grade of 5 indicates excellent stain removal; A grade of 1 indicates very poor stain removal • Sample brought to moisture equilibrium; Testing Conditions: 21°C (± 2°C) and 65%RH (± 5%RH) • AATCC Stain Release Replica version 2013 used for grading • Modified hand washing procedure using a soft cloth with 1% Tide® detergent solution and • 105⁰F water • Rinsed using a soft cloth and 80⁰F water • Air Dried Testing Results: Table 15a: Results from Soil Release Test on Leather with Coating System M K W W S O S Fr St U

Table 15b: Results from Soil Release Test on Leather Crust (no coating) M

K W W S O S Fr St U

As shown in Tables 15a and 15b above, the coated leather received all 5/5 grades, demonstrating excellent stain removal. The uncoated leather did not receive any 5.0 ratings. Example 12: Colorfastness to Light: Xenon Arc Test Test Method: AATCC TM16.3-2020, Test Method for Colorfastness to Light: Xenon-Arc - OPTION 3 Testing Information: • Option 3 - Xenon Arc Lamp, Continuous Light, Black Panel Option • Face of the material exposed. The test specimen is compared to original, unexposed specimen and is backed. • Shade change of the masked portion as compared to the original: 5.0 • If result of above is not a 5.0, the textile has been affected by some agent other than light, such as heat or a reactive gas in the atmosphere. The exact cause is unknown. • Xenon Test Chamber Model QSun Xe-2-HSE • Rotating drum horizontal specimen rack; 45 x 330 mm double panel holders, Panel Capacity = 15.5 • AATCC EP1-2020, Evaluation Procedure for Gray Scale for Color Change • Graded under Illuminant D65 "Daylight", Geometry Option C, Gretag Macbeth SpectraLight III • A grade of 5 indicates negligible or no color change; a grade of 1 indicates much color change • See Table IV - Reporting Form • Sample brought to moisture equilibrium; Grading Conditions: 21°C (± 2°C) and 65%RH (± 5%RH) Test Results: Table 16: Results from Colorfastness to Light Test

Example 13: Colorfastness to Perspiration Test Test Method: Test Method for Colorfastness to Perspiration – AATCC TM15-2013e Testing Information: • Number 10 Multi-Fiber Test Fabric • Acid Perspiration Solution = pH 4.3 ± 0.2 • Alkaline Perspiration Solution = pH 8.0 • AATCC EP2-2018, Gray Scale for Staining used for evaluation • AATCC EP1-2018, Gray Scale for Color Change used for evaluation • Graded under Illuminant D65 "Daylight", Geometry Option C, Gretag Macbeth SpectraLight III • A grade of 5 indicates negligible or no staining and negligible or no color change • A grade of 1 indicates heavy staining and much color change • Sample brought to moisture equilibrium; Grading Conditions: 21 °C (± 2 °C) and 65%RH (± 5%RH) • Note: Specimen size increased so cut edges of specimen were not in contact with edge of fiber strip Test Results: Table 17: Results from Colorfastness to Perspiration Test

Example 14: Polyurethane and Silk System Stability A polyurethane/silk system with mid- molecular weight silk may form a gel. The addition of silk and the type of silk will enable tuning of the final product. Table 18: Polyurethane/ Silk System Gel Formation

Bi

Example 15: Fourier Transform Infrared (FTIR) Imaging – Heated ATR Imaging For this FTIR analysis, a JASCO Heated ATR – Diamond Crystal was used. Two liquid silk solution samples (60 mg/mL) were tested. Instrument Information: Measurement Modes: Attenuated total reflectance (ATR) Objectives: A wide area microscopic ATR “ATR-5000-WG” was used.This instrument is a 1600×1600 μm imaging measurement by 1 contact. It is ideal for surface analysis of soft samples such as foreign matter, rubber, biological sample, etc. The FTIR results for plain leather can be seen in Fig.11. The FTIR results for coated leather can be seen in Fig.13. The FTIR results for top-coated leather can be seen in Fig.14. Table A. Secondary structure estimation of LS-22348_L T (C 3 4 4 5 5 6

6 7 7

Table B. Secondary structure estimation of ms-so-000339 T (C 3 4 4 5 5 6 6 7 7

Example 16: Fourier Transform Infrared (FTIR) Imaging – Macro ATR Imaging ATR measurements have been used to measure the coated rubber samples either with the single element MCT detector or the 32x32 FPA detector. Imaging with the FPA detector and a macro ATR accessory helps to resolve details of the coating distribution. Results can be seen in Figs.15A through 15C. Example 17: Biofinishing Coating System Validation Study The objective of this study was to document performance results with a Coating System described herein and compare it to the user needs requirements. Table 19. Summary of Test Results Ite # 1

₂ 3 4 5 6 7

Stain Resistance Test Summary of the results of the stain resistance test on leather treated with a coating system described herein can be seen in Table 20 below and Figs.16A through 16H. Table 20. Summary of Stain Resistance Testing on Coated Leather M W M K W Fr C C

Industrialization Trial Results Samples used can be seen in Table 21 below and Figs.17A- 17C. The results of this Trial are summarized in Table 21 below. Table 21. Summary of industrialization Trial Results on Coated Leather

Wet Color Fastness Rubbing Test / Wet Veslic Test Conditions and results for this test are summarized in Table 22 below and illustrated in Figs. 18A – 18I. Table 22. Summary of Wet CFR Test Conditions

Bally Flex Test Conditions and results for this test are summarized in Table 23 below and Figs.19A – 19D. Table 23. Summary of Bally Flex Test Conditions S N A N A N A N A

From this results, it was shown that the substrate and coating system passed a Bally Flex test up to 20,000 cycles. The substrate and coating system passed a Bally Flex test up to 1,000 cycles, up to 5,000 cycles, up to 10,000 cycles, up to 15,000 cycles, and up to 20,000 cycles. The coating system did not separate from the substrate. Tape Test Conditions and results for this test are summarized in Table 24 below. Table 24. Summary of Tape Test Conditions and Results S

N A N A N A N A

Conclusions • L1 system passed technical user need requirements with conditions approved at Stage Gate 2. • L5267 is not stable upon freezing based on supplier provided Technical Data Sheet and Safety Data Sheet. Temperature controlled storage and transportation was implemented to ensure quality. The coating system of Example 18 is deemed to be validated based on results of the tests described herein. Example 18: Adhesive Tape Test for Basecoat Testing The following coating recipes were used for this Adhesive Tape Test. Table 25. Basecoat Recipes for Adhesive Tape Test HA _HA

Table 26. Adhesive Coat Test Summary

H H H

Table 27. Summary of Tape Test Results S H H H H

H H H H H

Based on the results shown in Tables 26 and 27, there was no delamination. This demonstrates the effectiveness of the coating system described in Table 25. The samples were then cut in half and milled for three hours, then the adhesive test was repeated. The milling includes processing the samples in a dryer for 3 hours using a mix of ballast composed of scrap leather pieces and wool panels. The updated Adhesive Coat Test Summary results are shown below in Tables 28 and 28 and Figs.21 and 22A- 22I. Table 28. Updated Adhesive Coat Test Summary Sa # H H H H H H H H

H

Table 29. Summary of Updated Tape Test Results S H H H H H

H H H H

Based on the results of Tables 28 and 29 and Figs.21 and 22A- 22I, even after the milling process, the coating system still proved effective. Samples were also tested after CFR application before and after the milled basecoat. Two HA1 samples were tested by the Adhesive Tape Test, one that was not milled before the topcoat was applied and one that was milled before the topcoat was applied. The results can be seen in Table 30 below and Figs.24A – 24B. Table 30. Summary of Updated Tape Test Results S H m be to H m be to

Example 19: Leather Coating Recipes for a Coating System The following formulations summarized in Table 31 are non-limiting exemplary coating recipes in accordance with a coating system of the present disclosure. Table 31. Exemplary Coating Recipes

Table 33 provides a short description of the ingredients included in the exemplary recipes of Table 31 and used throughout the present description. Table 33. Ingredients Legend L BI BI

D D M M M U B E B B S T I A A A A A A A A A A A A B B E E

Example 20: Basecoat for Leather A combination of hydrolyzed silk, gelatin, and elastin proteins with a plasticizer and transglutaminase crosslinker to deliver a fully biobased base coat to be applied to leathers during the finishing process. Base coats are commonly used in the leather manufacturing industry as a method of delivering pigments and covering crust repairs. These products are utilized to create favorable hand feel and optical properties by modifying the leather surface. During finishing process, they are combined with a topcoat to create a color fast leather product with appealing tactile properties. However, current commercially available base coat formulations are (i) generated from petrochemical resources causing sustainability issues and (ii) non-biodegradable resulting in problems with processing waste disposal and finished leather product disposal. In some embodiments, the disclosure provides a product which delivers an optically uniform, stretchy, and elastic coat onto a leather surface and anchor the topcoat to the leather. Description Casting to Film 1. Take 40 grams of prepared basecoat solution and pour in a silicon mold. 2. Place filled silicon mold in a convection oven for 12 hrs at 140 ºC. 3. Remove mold from oven and allow film to equilibrate for 1 hr. 4. Remove film from silicon mold. Solution Preparation (Crust Adhesive Coat) 1. Add 414 grams of water to a container 2. Add 85 grams of low molecular weight silk solution to the solution and stir for 5 minutes. 3. Add 1.25 grams of Melios 09s11 crosslinker to the solution and stir for 5 minutes. Solution Preparation (Base Adhesive Coat) 1. Add 414 grams of water to a container 2. Add 85 grams of mid molecular weight silk solution to the solution and stir for 5 minutes. 3. Add 1.25 grams of Melios 09s11 crosslinker to the solution and stir for 5 minutes. Solution Preparation (Basecoat) 1. Add 1 kilogram of water to a container and heat to 60 °C. 2. Add 2.5 grams of gelatin and 5 grams of glycerol to the container and stir for 30 minutes. 3. Remove the solution from heat. 4. Add 10 grams of elastin to the solution and stir for 5 minutes 5. Add 10 grams of transglutaminase/maltodextrin powder and 170 grams of mid molecular weight silk solution into the solution and stir for 5 minutes. 6. Adjust the solution pH to 10 using ammonia. 7. Add 20 grams of TP Black E pigment from First Source Worldwide. Solution Preparation (Topcoat) 1. Add 500 mL of 100% ethanol to a container. 2. Add 8.3 grams of triethyl citrate and 13.5 grams of Prisorine (isostearic acid) to the solution and stir for 5 minutes. 3. Slowly, to prevent clumping, add 12.5 grams of ethyl cellulose to the solution and stir overnight (at least 12 hours). Note, make sure to stir in a covered vessel to prevent evaporation of ethanol and concentration of ethyl cellulose. Spray Coating on Fabric 1. On an unfinished leather skin, spray the crust adhesive coat using a 1.3 mm spray nozzle at a 45º cone pattern and 35-40 psi adding 1 gr/ft² of material. 2. Take the sample and dry in an oven at 130 ºC for 30-60 seconds (until dry). 3. Next, spray the base coat onto the leather again using a 1.3 mm spray nozzle at a 45º cone pattern and 35-40 psi adding 1 gr/ft² of material. 4. Take the sample and dry in an oven at 130 ºC for 30-60 seconds (until dry). 5. Iron the sample using a roller iron at 98 ºC under 50 kg/f pressure at a 6 m/min speed. 6. Apply two more coats of basecoat formula using steps 3 and 4. 7. Finally, spray the topcoat formula onto the leather using a 1.3 mm spray nozzle at a 45º cone pattern and 45-50 psi adding 1 gr/ft² of material. 8. Take the sample and dry in an oven at 130 ºC for 30-60 seconds (until dry). 9. Repeat steps 7-8 two more times. 10. Iron the sample using a roller iron at 98 ºC under 50 kg/f p^{ressure at a 5 m/min speed.} P_{erformance Testing Methods} Film Testing All films were tested in house qualitatively based on bendability, stretch, elasticity, and water drop resistance. Each test was performed on a scale of 1- 4 with 1 being the worst and 4 being the best. -For bendability, the film was creased in two directions if the film could not bend it was given a score of 1 and if it could crease without leaving a mark it was given a score of 4. -For stretch, the film was pulled into opposite directions, if it broke without any elongation, it was given a score of 1 and if it could elongation past twice its size it was given a score of 4. -For elasticity, the film was stretched, if it could not stretch any distance without permanently deforming it was given a score of 1 and if it could stretch to twice its length and still recover its shape it was given a score of 4. -For water drop resistance, a drop of water was applied to the surface using an eye dropper, if the film immediately dissolved it was given a score of 1 and if no change occurred after the water was applied and evaporated it was given a score of 4. Leather Testing All leather coated samples were tested using the Veslic test to ensure colorfastness to rubbing and bally flex test to ensure adhesion between all layers and to prevent cracking. The Veslic test follows the ISO 11640 testing procedure and the bally flex test follows the ISO 5402 testing procedure. Test Results Film Test Results All film test results can be seen in Table 34. From the film testing data, the silk/elastin/gelatin formulation crosslinked by transglutaminase gives the best films. In all formulations, activated silk (AS-105) and gelatin are present to give the film structure and body. Glycerol is also added to the film as a plasticizer to add bendability. Originally, Etocas 200 (a highly ethoxylated castor oil) was added to make the film soft as seen in experiments 1-3, however, the bendability was sometimes subpar, and the films had little to no stretch and elasticity as well as poor water resistance. To increase water resistance and stretch Etocas 200 was substituted with Span 120 (sorbitan isostearate). This increased the water resistance, however, just like Etocas 200 it was lacking in stretch elasticity as seen in experiments 4-5. Elastin was used to increased stretchability and transglutaminase was tested to improve elasticity. AS seen through experiments 7-18, stretchability and elasticity were greatly improved when elastin and transglutaminase was added. To find the optimal concentrations standard curves were made for each ingredient as can be seen in experiments 19-36, leaving the optimal ratio to be 0.25:1:1 Gelatin to Transglutaminase to Elastin. With the optimal ratio identified, the optimal concentration of total non-silk solids in the solution was investigated resulting in an optimal concentration of 2.75% additives. Leather Coating For each leather coating experiment, four layers were applied. First an adhesive layer consisting of low molecular weight activated silk (AS-104) and Melios-09s11 crosslinker was applied to the leather crust. Next the basecoat was applied at a 3 g/ft2 application rate. Then an adhesive layer between the basecoat and topcoat consisting of mid molecular weight activated silk (AS-105) and Melios-09s11 was applied to the surface. And finally, the topcoat was sprayed on the surface.

Veslic Test Results All Veslic test results can be seen in Table 35. For both samples with no basecoat and Etocas 200 as the main additive, if the topcoat contains isostearic acid it will rub off causing pigments to leach onto the scrubbing pad as can be seen in experiments 1-3. However, if Span 120 is used in the topcoat it will stay on up to 300 cycles as can be seen in experiments 4-5. If Span 120 is used in the basecoat with a crosslinker, the topcoat will prevent the pigment from leaching onto the scrubbing pad. However, the surface of the leather becomes deformed after rubbed (except for the use of Rodalink 3315 crosslinker) and the use of a petrochemical derived crosslinker makes this formulation not 100% biobased. But, if elastin is used with a transglutaminase, no pigment leeches out as well as the surface remains unaltered as can be seen in experiment 12. The use of elastin and transglutaminase also makes the formulation 100% biobased. Bally Flex Test Results All bally flex test results can be seen in Table 36. The use of Etocas 200 in the basecoat causes samples to undergo total topcoat detachment from the basecoat at 8000 cycles as can be seen in experiments 1-2. Furthermore, by removing Etocas 200 from the basecoat the samples do not undergo total detachment, however, they still experience slight detachment as can be seen in experiments 3-4. Even experiments which contain Span 120 in the basecoat undergo slight detachment as can be seen in experiments 5-6. But samples containing elastin and transglutaminase in the basecoat do not undergo any form of detachment up to 8000 cycles. Example 21: Basecoat and Topcoat Components for Coating System Below are examples of the amount of various products that may be included in the topcoat and basecoat in accordance with a coating system described herein. Table 37. Basecoat and Topcoat Grams per sq. ft.

Example 22: BIOPUR 3015 Adhesive Study The minimum viable amount of BIOPUR 3015 needed to pass the adhesion test was evaluated. Table 38. Amount of BIOPUR 3015 Needed to Pass the Adhesion Test

As can be seen in Table 38, the cutoff for passing the scotch tape test is around 0.5% BIOPUR 3015. To further evaluate variations in performance, water resistance was measured by adding a drop of water to the surface and observing if it absorbs into the leather over a period of 5 minutes.

A study was then performed adding different numbers of layers of 10% BIOPUR 3015.

To better understand the effects activated silk has on the topcoat adhesion. An adhesive layer with BIOPUR 3015 and the minimum amount of silk needed to reach 80% biobased was made.

Example 23: MATTING AGENTS System Challenges and Design Challenges for Matting Agent with L1 System Carrying capacity of 2.5% ethylcellulose: (i) low solids usage in topcoat generally limits total matting agent < 2%; (ii) sufficient matting at low concentrations requires silica (vs mineral, clay, or cellulose-based matting agents); and (iii) poor relative burnish resistance in dispersed silica coatings. Depth of matte vs polish resistance: (i) deeper matte coatings show more visible polishing for the same Δ gloss; (ii) decreasing extent of matte to ease polishing yields overly glossy coatings; and (iii) best silica matting agents (Acematte® 3300) show visible polishing at concentrations > 0.40%. Performance testing: Bally flex trade-off with silica content. System Design Design strategy: 2-part matting agent. Minority component: silica. Silica at a concentration of 0.25 – 0.40% provides majority of gloss reduction at concentrations low enough to avoid polishing. Interchangeable plasticizer solvent at 3.5 – 5% incorporation in final form. Majority component: polymer host. Polymer (PU, Decosphaera®) at a concentration of 0.50 – 1.00% provides additional gloss reduction, while being fully resistant toward polishing. It is also possible that the polymer acts as host for silica with protection against polishing. Formulation A Original Formulation A is presented in Table 39 and modified Formulation A (stabilized formulation) is presented in Table 40. Table 39. Original Formulation A.

Table 40. Modified Formulation A – Stabilized Formulation.

Table 41. System analysis.

Table 45. L1 BioFinishing System with Formulation A only – gloss units analysis.

Table 46. L1 BioFinishing System with Formulation A only – spectrophotometer analysis.

Example 24: FORMULATION A: L1 MATTING AGENT. 2-Part Matting Agent System A schematic of the preparation of 2-part matting agent system is presented in Figure 50. Matting Agent A • Silica matting agent: Acematt® 3300 – 5.0%. • Stabilizer: Aerosil® R972 – 0.5%. • Solvent (plasticizer): Triacetin – 94.5%. • The silica matting agent, stabilizer, and solvent were stirred to provide a silica solution (i.e., solution (a) or Matting Agent A). Matting Agent B • PU matting agent/host: Decosphaera® – 40.0%. • Stabilizer: Solagum^TM Tara – 0.2%. • Solvent: water – 58.8%. • The PU matting agent/host, stabilizer, and solvent were stirred to provide a PU dispersion (i.e., solution (b) or Matting Agent B). Topcoat Solution • 50% of 5% ethylcellulose in MP was diluted in 50% MP to provide a topcoat solution (i.e., solution (c)). Matte Topcoat • Matting Agent A (5.00-8.00%) and Matting Agent B (1.25-2.50%) were added into the topcoat solution (90-93%) to provide the final formulation, the Matte Topcoat. Exemplary Matte Topcoat formulations are shown in Table 47. Table 47. Modified Formulation A: L1 Matting Agent.

Example 25: PLASTICIZERS Test Evaluation Step 1: Preliminary screening of flexibility, homogeneity, migration/separation by casting films with ethyl cellulose topcoat. Step 2: Down selected plasticizers were tested on one leather type and evaluate for visual appearance (cracks, discoloration, lines, white dots), Colorfastness to rubbing (CFR), adhesion (tape test) and water drop (penetration thru finish) after milling. Step 3: Candidates from the down selected list were further tested on 3 additional leather types. Testing was performed before and after milling: visual appearance, bally flex, gloss, CFR, tape test, water drop. Additionally, hand was also assessed. Candidates that passed Step 3 were sent to be generate articles for client feedback. Step 1 – Preliminary Screening Candidate solvents are presented in Table 48. Table 48. Solvent candidates.

In general, glyceryl moiety and hydroxyls (polyols) were shown to perform better than others. Step 2 – Downselection Selected PLs are presented in Table 49 and the trade name and chemical name are presented in Table 50. Table 49 Summary of selected PLs.

Table 50. Trade names and chemical names of selected solvents. E _Je P Ha

Step 3 – Leather Type Evaluation Leather type evaluation before and after milling are presented in Table 51 and Table 52, respectively. Figure 51A, Figure 51B, and Figure 51C show exemplary gray, brown, and black leathers with CAP-7, MHG, and DPGDB, respectively.

Table 51. Leather type evaluation with plasticizers before milling.

Table 52. Leathertype evaluation with plasticizers after milling.

Example 26: Top Coat Using Spray Nozzles of Varying Diameters. Setting the level of the spray material The pressure was set at 4 bar. Procedure for creating the top coat using spray nozzles of varying diameters Ethyl cellulose with 2.5%; 5%; and 7% concentration was used. A 6 x 6-inch piece of brown with a standard base coat-L5267 was used. Four layers were applied, and the mass before and after each coating was measured. The material quantity per square foot was calculated. Viscosity of ethyl cellulose Viscosity of ethyl cellulose with 3 different concentrations in methoxy propanol using LV-02 (62) speed of 1.5 rpm: (i) 2.5 % ethyl cellulose, 120 cps; (ii) 5.0 % ethyl cellulose, 1480 cps; and (iii) 7.0 % ethyl cellulose, 8520 cps.

1st Before milling 2nd After Milling 1st Before milling H g

Spray nozzle S'

5 £ r £ Diameter 5 t*n) p p p -4 p p L0822 Concentration g g g g g g g ' g ' g

£Z£

2nd After Milling 1 st Before milling 2nd After Milling

Spray nozzle

£ £ £ r 5 £ r g £ Diameter

L0822 C ti

The weight of the coated sample versus the diameter of the spray nozzle is presented in Figure 52. Images of the samples at varying ethyl cellulose concentrations in methyl propanol with milled and not milled crust leather are presented in Figure 53-Figure 53F. EXAMPLE 27: Formulation A Matte Testing. Figure 54 shows test results from Formulation A matte testing. The SADESA laboratory test standards (segment: performance) are presented in Table 54. Table 54. SADESA Laboratory Test Standards. _A _A Cr Cr H C Gr ( Li

R Vu C S (*

[0001] Additional tests for WP products are presented in Table 55. Table 55. Additional tests for WP products. (K P P a P p

Table 56.

Table 57.

EXAMPLE 28: Formulation A Matting Agent Testing. Formulation A screening on L5267 is presented in Table 58 and Table 59. Table 58. Formulation A Screening on L5267 – Gloss Units. f eu

Table 59. Formulation A screening on L5267 – Spectrophotometer Analysis. f eu

Formulation A screening with all auxs is presented in Table 60 and Table 61. As shown in the Tables, some gloss is lost after ironing as expected using a polished plate, but after milling the gloss units are similar to before ironing, and there were no significant changes in color. Table 60. Formulation A Screening with All Auxs – Gloss Units.

f eu

Table 61. Formulation A Screening with all Auxs – Spectrophotometer Analysis. f

eu

Figure 55A-Figure 55N show images of Euroleather (top) and Fracopel (bottom) before and after ironing. Figure 56A-Figure 56N show images of Fragopel and Euroleather after (top) and before (bottom) milling. It was found that Ceral 63/N, a carnauba based auxiliary, significantly breaks and delaminate the topcoat after 8hrs of milling. Table 62 and Table 63 show Formulations A, B, C, and D screening on L5267. Table 62. Formulation A, B, C, and D Screening on L5267 – Gloss Units. fr

Table 63. Formulation A, B, C, and D Screening on L5267 – Spectrophotometer Analysis. f eu

Figure 57A-Figure 57L show Euroleather (left) and Fracopel (right) with Formula ABCD before iron, after ironing, and after milling. All samples before ironing have some dots, in order of amount: Formulation C, B, A, D. After ironing all dots disapperared. After milling, all samples presentED breaks, in order of amount: Formulation D, C, A, B. Figure 58A and Figure 58B show vulcanization tests. Table 64 and Table 65 show Formulation 061 testing results. Table 64. Formulation 061 screening – gloss units. f eu

Table 65. Formulation 061 screening – spectrophotometer analysis.

f eu

Table 66 and Table 67 show Formulation 061 with part 24 testing results. Table 66. Formulation 061 with part 24 screening – gloss units. fra c b L 1 pi

Table 67. Formulation 061 with part 24 screening – spectrophotometer analysis. fr L pi

Table 68 and Table 69 show Formulation 072 with part 24 testing results. Table 68. Formulation 072 with part 24 screening – gloss units. f f cr Eu

Table 69. Formulation 072 with part 24 screening – spectrophotometer analysis. cr E

General Observations of Formulation 072 with 24 parts • 072-1: Part AUX-SAS-071-1 required mixing before preparing the application formulation. The viscosity 119.1cp. On Fracopel brown and black the appearance is inconsistent on the surface, spotty. • 072-2: The application solution did not filter directly, it required manual forcing with a stirrer bar through the filter. The viscosity was 136.5cp. • 072-3: The viscosity was 104.7. Figure 59A-Figure 59C show the finishing resistance when handling leather after spraying and before ironing. EXAMPLE 29: Matting Agent Summary Data. Table 70 shows the matting agent summary data.

⁰ ₅ O W-₃ ³ ₀ ⁵-² ₇ ² ₂ ³ ₀ ._a ^t _a D y^r _a m m_u S ^t _n ^e _g A gⁿi_t ^t _a M . 0₇ _e ^l b a T)))))))npp C Cii C Co - -irr)00

Table 71 shows the Experiment summary. Table 71. Experiment Summary. Ex scr ind scr vs H3 scr ind scr age sho De age thir Co car and De of and Co (lo rec for Pla De rep fee car Ma for stu De 330 pho lea For For co Ed No sa han

Ex Shi bat test PU im Pla ma dis Pla lea sili dis PU im PU Pro PU Pol me Intr Tar Intr Tar Ac For on For con per Mu pla MV 20) MV han De sta

Ex For at s MV con Pla SY sol For Sta dis

Select formulations are presented in Table 73.

⁰ ₅ O W-₃ ³ ₀ ⁵-² ₇ ² ₂ ³ ₀ ₈ 7₃ _. ^s _n o_i ^t _a ^l _u m^r _o F ^t _c ^e _l ^e S _. ³ ₇ _e ^l b a T

Table 74 shows evaluated matting agents and waxes. Table 74. Evaluated matting agents and waxes.

Table 75 shows the reference data. Table 75. Reference data.

Table 76 shows a list of matting agents. Table 76. Matting agents. M Ac Ac SY Im Im Im La SY Op Ec Na Kö Lo Ac Ad Ad

O O Ul Th M Al

Table 77 shows a burnish resistance list. Table 77. Burnish resistance list. B N M M M D D Bi Bi Bi D Ci La Sc O pr M Bi Cr Et

Table 78 shows exemplary properties of samples of Formulations A, B, C, and D. Table 78. Exemplary properties of samples of Formulations A, B, C, and D. Re en A PC 00 01 A PC 00 02

AU PC 00 03 A PC 00 04

Table 79 shows exemplary properties of samples of Formulation 052.

EXAMPLE 30: LUMOS II CHARACTERIZATION OF RUBBER SAMPLES.

LUMOS II Stand-Alone FT-IR Microscope was used to characterize rubber samples.

ATR measurements were used to measure the coated rubber samples either with the single element MCT detector or the 32x32 FPA detector. Imaging with the FPA detector and macro ATR accessory helped resolved details of the coating distribution.

Figure 60 shows IR spectra of the samples by LN-MCT detector. Figure 61 shows macro ATR imaging of the sample with an adhesive base coal. Figure 62 shows macro ATR imaging of the sample with the top coat.

EXAMPLE 31 : SEM images of leather samples tested with BSE (SE2).

Figure 63 shows a cross-section of uncoated leather. Unevenness on the surface is visible.

Figure 64 shows a cross-section of basecoat coated leather. Basecoat is sprayed at 4g/sqft of basecoat; (1) 2 x passes of 1 g/sqft; (2) ironed at 90 °C with 50Kg/cm of pressure at 6m/min drum speed; and (3) 2x passes of 1 g/sqft. Smoother surface than uncoated leather is visible. Basecoat comprises 0.4% silver tagged silk. Due to low concentration of silk, distribution of silk in coating is low. Thickness of coating is 3 - 5 micron.

Figure 65 shows coated leather with LI system. Basecoat is sprayed at 4g/sqft of basecoat and comprises 0.4% silver tagged silk: (1) 2 x passes of 1 g/sqft; (2) ironed at 90 °C with 50Kg/cm of pressure at 6m/min drum speed; and (3) 2x passes of 1 g/sqft. Topcoat is sprayed at 6g/sqft: (1) 1 pass at 6g/sqft and (2) ironed at 90 °C with 50Kg/cm of pressure at 6m/min drum speed. Thickness of topcoat is 2 - 3 micron. After processing, the topcoat is integrated to the basecoat with a water repellent surface.

Figure 66 shows further magnification of silver tagged silk in LI system. Basecoat/topcoat composite indicated by silver tagged silk throughout the coating.

Figure 67 shows a schematic of the layers formed. Heat and pressure during processing create composite layer between topcoat and basecoat with a heavier concentration of basecoat closer to the leather surface and a higher concentration of topcoat at the surface. Topcoat layer is fully intact for water repellency as confirmed by wet veslic testing. Example 32: Scaleup Methods gradie two v reacti planes bench lower about °C, ab about about Extra Cocoo Ext w Sodiu Ext w Extrac Rinse Rinse Rinse Numb

Dissol Fibroi 9.3 M vol Dissol temp Comb time React time Notes

Example 33: Modified Peptides A novel method is disclosed to generate compositions of polypeptides that are derived from B. mori silkworm cocoons and comprised of natural and modified polypeptides. These two novel compositions are called Low Skid and Mid Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at two different temperatures and times to achieve the different compositions for Mid and Low silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Low Skid and Mid Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties. Low Skid silk/modified polypeptide composition does not self-assemble at 5 mg/mL. Low Skid silk/modified polypeptide composition comprises of two main populations of silk/modified polypeptides; one population (AS22) that does not self-assemble under conditions that promote self- assembly at 5 mg/mL and is rich in negatively charged amino acids; a second population of polypeptides (AS12) that self-assemble fast at 5 mg/mL and are depleted on negatively charged amino acids. When AS12 and AS22 are combined at a ratio of 50% each the average molecular weight of the mixture becomes the same as Low Skid silk/modified polypeptide composition. Thus Low Skid silk/modified polypeptide composition consists of 50% AS12 and 50% AS22 silk/modified polypeptide compositions. Mid Skid silk/modified polypeptide composition comprises of two main populations of silk/modified polypeptides; one population (AS11) that self-assemble slower than Mid Skid silk/modified polypeptides, under conditions that promote self-assembly at 5 mg/mL and is rich in negatively charged amino acids; a second population of polypeptides (AS1) that self-assemble faster than Mid Skid silk/modified polypeptides, under conditions that promote self-assembly at 5 mg/mL and are depleted on negatively charged amino acids. When AS11 and AS11 are combined at a ratio of 50% each the average molecular weight of the mixture becomes the same as Mid Skid silk/modified polypeptide composition. Thus, Low Skid silk/modified polypeptide composition consists of 50% AS1 and 50% AS11 silk/modified polypeptide compositions. Both Low Skid and Mid Skid silk/modified polypeptide compositions contain modified peptides that were determined after analysis with Mass Spectrometry. Low and Mid Skid silk/modified polypeptide compositions described in this disclosure are never produced before compositions of silk-derived and modified polypeptides that when isolated display a wide range of behaviors, from extreme self-assembly to solubility and stability over time in various buffers and various average molecular weights and polydispersities. These novel silk-derived polypeptide compositions contain unique modified amino acid sequences that result from a unique silk processing method and scaleup. The tight controls around temperature, silk concentration, salt concentrations, physical agitation and purification allow us to tune at each step of the process the unique peptide compositions in the natural/modified silk species to design for specific performance criteria. Some of constituent polypeptide compositions display biological activity and could be used as therapeutic candidates. Silk is a versatile material that can be used in many applications from development of implantable medical devices to the development of soluble polypeptide formulations of medicinal value. A major challenge with silk polypeptides in solution is their tendency to self-assemble and aggregate, making the control of their solubility very difficult. Also, the kinetics of gel/film formation cannot be controlled in a predictable way. This novel silk/modified peptide compositions contain populations of peptides that allows to control their properties and develop products with predictable and desired properties. The disclosed compositions contain a collection of many polypeptides with different properties. Silk has been characterized mostly based on its molecular weight and polydispersity, and no mixture of silk/modified polypeptides has been characterized or has been generated. As disclosed herein, a unique large scale process is used to generate compositions of silk/modified polypeptides. Low/Mid skid silks begin their process to remove sericin using sodium carbonate at specific silk mass, sodium carbonate, and water ratios. Multiple different temperature washing cycles 100 °C and 60 °C and agitation is also key in producing the specific natural/modified compositions. The silk is then dried to remove water at a specific temperature that maintains the silk composition. Next the silk is dissolved in a high concentration of Lithium Bromide at 103 °C and 125 °C for 1 and 6 hours respectively. The time and temperature allow for fine tuning the degree of post translational modifications that give the unique polypeptide compositions. The silk is then purified to remove Lithium Bromide and optionally concentrate the silk. For the downstream characterization of isolation of the various silk/modified polypeptide compositions chromatographic techniques were employed, biochemical/biophysical techniques, and cell biology methods. To characterize/separate novel Low and Mid Skid silk/modified polypeptide compositions a combinations of Ion Exchange Chromatography fractionation, analytical methods, and biochemical dissection were used to characterize its properties. Generation of Low and Mid Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100 °C and 60 °C with sodium carbonate and then dried at 60 °C. The silk is then dissolved in 9.3 M Lithium Bromide at 103 °C for 1 hour for Mid silk and 9.3 M Lithium Bromide at 125 °C for 6 hours for Low silk. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 KDa cutoff PES hollow fiber membranes, and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Low and Mid Skid/modified polypeptide compositions Isolation of the AS22 silk/modified polypeptide composition component of Low Skid silk/modified polypeptide composition. To isolate AS22 it was fractionated Low Skid silk/modified polypeptide compositions using HiTrap Q Sepharose Anion Exchanger (Figure 68, 69). Tris was added in the silk preparations to a final concentration of 50mM Tris-HCl pH=8.0. Silk was centrifuged before loading the HiTrap Q Sepharose column to remove any preformed aggregates. Low Skid silk preparation solutions have a characteristic yellow hue. The flow through from the HiTrap Q Sepharose column was transparent. AS22 eluted with 1M NaCl and it has an intense yellow hue. When AS22 formulation is analyzed with an analytical SEC column (see materials and methods) with HPLC it has an average molecular weight (MW) of about 35 kDa and Polydispersity (PDI) of 2.3 (Figures 70, 71). This molecular weight and polydispersity are distinctive and different from Low Skid silk/modified polypeptide composition (MW about 19.5kDa and PDI 2.2) and Mid Skid silk/modified polypeptide composition (MW about 38kDa and PDI 2.4) (Figures 70, 71). When AS22 and Low Skid silk were analyzed in Isoelectric Focusing Polyacrylamide gels, it was found that 22M silk peptides had pIs 3-6 and some species with pIs of about 9.6, whereas Low Skid silk also contains peptides that span the whole range of pIs, from 3 to 9.6 (Figure 72). Isolation of the AS12 silk/modified polypeptide composition component of Low Skid silk/modified polypeptide composition. To develop AS12 a combination of Ion Exchange Chromatography (IEX) fractionation was used to purify the formulation, analytical methods and biochemical dissection to characterize its properties. To isolate AS12 Low Skid silk preparations was fractioned using HiTrap Q Sepharose Anion Exchanger (Figure 68, 69). Tris was added in the silk preparations to a final concentration of 50mM Tris-HCl pH=8.0. Silk was centrifuged before loading the HiTrap Q Sepharose column to remove any preformed aggregates. The flow through from the HiTrap Q Sepharose column was collected and was designated AS12. AS12 is colorless. AS12 silk formulation is composed of short silk/modified polypeptides depleted in negative charges. When AS12 was analyzed with analytical Size Exclusion Chromatography, it has an average molecular weight (MW) of about 12 kDa and Polydispersity (PDI) of 1.7 (Figures 70, 71). This molecular weight and polydispersity are distinctive and different from Low Skid silk/modified peptide composition (MW about 19.5 kDa and PDI 2.2) and Mid Skid silk/modified peptide composition (MW about 38 kDa and PDI 2.4) (Figures 70, 71). When AS12 and Low Skid silk/modified peptide composition were analyzed in Isoelectric Focusing Polyacrylamide gels, it was found that AS12 silk peptides had a pI of about 9-10, whereas Low Skid silk also contains peptides that span the whole range of pIs, from 3 to 9.6 (Figure 72) with most of them concentrated around pI 3-5.5. Isolation of the AS1 silk/modified polypeptide composition component of Mid Skid silk/modified polypeptide composition. To isolate AS1 Low Skid silk preparations were fractioned using HiTrap Q Sepharose Anion Exchanger (Figure 68, 69). Tris was added in the silk preparations to a final concentration of 50 mM Tris-HCl pH=8.0. Silk was centrifuged before loading the HiTrap Q Sepharose column to remove any preformed aggregates. The flow through from the HiTrap Q Sepharose column was collected and was designated AS1. AS1 has a MW of about 28kDa and PDI of 1.7-2.1 (Figure 70, 71). Mid Skid silk/modified peptide composition has MW of 37kDa PDI 2.0 (Figure 70, 71). Isolation of the AS11 silk/modified polypeptide composition component of Mid Skid silk/modified polypeptide composition. To develop AS11 a combination of Ion Exchange Chromatography (IEX) fractionation to purify the formulation, analytical methods and biochemical dissection to characterize its properties was used. To isolate AS11 Mid Skid silk/modified peptide composition preparations was fractionated using HiTrap Q Sepharose Anion Exchanger (Figure 68, 69). Tris was added in the silk preparations to a final concentration of 50 mM Tris-HCl pH=8.0. Silk was centrifuged before loading the HiTrap Q Sepharose column to remove any preformed aggregates. The elution from the HiTrap Q Sepharose column was collected and was designated AS11. AS11 formulation has a molecular weight (MW) of about 53 kDa and Polydispersity (PDI) of 2.8 (Figure 70, 71). This molecular weight and polydispersity are distinctive and different from Mid Skid silk/modified peptide composition (MW, about 37kDa and PDI 2.4) (Figure 70, 71). Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self assembly assay and data derived from it. To study the stability of AS1 in solution self-assembly assays was performed. AS1 silk at 5 mg/mL self assembles very fast. The absorbance at 550 nm curves of the self- assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is: fx=Amax1+e-k(t-t0.5) A_max is the maximum density of the gel formed k is the Self Assembly Rate Factor t_0.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve (see figure 73A the red dotted lines for a better demonstration of how these factors were calculated from the self-assembly experiments) Another parameter introduced to characterize the propensity of silk to form gels is the Self Assembly Factor which is: f_SAF=1t_0.5×A_max×1000 Using the experimental data from the self-assemble assays performed with the various novel isolated silk polypeptides these parameters calculated and use to dissect their properties (Figure 73, 74, 75). Four parameters were in focus, collectively refered to as Self-assembly kinetic factors; the Self-Assembly Rate Factor (SARF), A_max, t0.5, and the Self Assembly Factor (SAF) (Figure 73, 74, 75). The SARF shows how fast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed; A_max shows how dense is the gel that is formed after self-assembly is complete, t0.5 shows how long it takes for the self- assembly reaction to reach the point where gel density is Amax2 and SAF shows the propensity of silk to self-assemble (Figure 73, 74, 75). AS1 silk/modified polypeptide composition has the fastest self-assembly kinetics. Self-assembly assays as described before, revealed that AS1 self-assembles very fast , much faster than Mid Skid silk/modified peptide compositions (Figure 73, 74, 75). Mid Skid silk/modified peptide compositions was used as a positive control and shows fast self- assembly kinetics (Figure 73, 74, 75). AS11 silk/modified polypeptide composition has the fastest self-assembly kinetics. Self-assembly assays as described before, revealed that AS11 self-assembles fast but not as fast as Mid Skid silk/modified peptide compositions (Figure 73, 74, 75. Mid Skid silk/modified peptide compositions was used as a positive control and shows fast self- assembly kinetics (Figure 73, 74, 75). AS12 silk/modified polypeptide composition is the component of Low Skid silk/modified polypeptide composition that promotes self-assembly. Self-assembly assays as described before, revealed that AS12 self-assembles fast but not as fast as Mid Skid silk/modified peptide compositions (Figure 73, 74, 75. Mid Skid silk/modified peptide compositions was used as a positive control and shows fast self- assembly kinetics (Figure 73, 74, 75). AS22 silk/modified polypeptide composition is very stable in aqueous solution and doesn’t self-assemble. Self-assembly assays as described before, revealed that AS22 displays a remarkable stability and doesn’t self-assemble even in conditions that promote silk self-assembly. Mid Skid silk was used as a positive control and shows fast self-assembly kinetics (Figure 71, 72, 73). When AS1, AS11, AS12 and AS22 silk/modified polypeptide compositions are combined at different ratios they result in compositions with unique properties. To better understand the properties of the silk/modified polypeptide compositions (Figure 73, 74, 75) a series of mixtures were created (see table 1). The resulting compositions display a unique combination of properties in self-assembly assays (Figure 73, 74, 75). Mixtures of AS1 and AS11 (AS2-10) and AS12 with AS22 (AS13-AS21) all display a unique combination of self-assembly kinetics (Figure 73, 74, 75). This information can be used to create silk/modified polypeptide compositions with specific desired properties. Materials and Methods used for the generation and characterization of AS1- AS28. Anion Exchange Fractionation of Silk. Low Skid silk was provided at a concentration of 60 mg/mL. Low Skid silk was centrifuged at 20,000 x g, at 4 °C for 15 min to remove any aggregated material. For the silk fractionation Q-Sepharose prepacked columns connected to an AKTA pure 25 L or columns packed with Q-Big Beads resin were used. All buffers used were filtered through a 0.45μm PES filter and degassed with sonication. Centrifuged Low or Mid Skid silk was loaded on 5 x 5mL HiTrap Q HP columns washed with 10 column volumes of 50mM Tris pH=8.0, 10 column volumes of 50mM Tris pH=8.0, 1M NaCl and finally 10 column volumes of 50mM Tris pH=8.0.100mL of centrifuged Low Skid silk were loaded on the column with a flow rate of 5mL/min. The flow-through was collected. The column was washed with 50 mM Tris pH=8.0 until the absorbance at 280nm [A280] got to 100 AU. Bound protein was eluted in one step with 50mM Tris pH=8.0, 1M NaCl and all fractions with absorbance [A₂₈₀] >500AU were pooled together.20mL of the Low Skid silk (LS) that was used for the fractionation, the flow through (QFT) and the pooled elution fractions (QE) were placed in dialysis bags (Sigma D9652-100FT, Dialysis tubing cellulose membrane avg flat width 33mm, 1.3in., and were immersed in 50 x volumes of 50mM Tris pH=8.0. Samples were flash frozen in liquid nitrogen and stored at -20^oC until they were used. Before use samples were thawed slowly at 4 ^oC or on ice. Analytical/Protein Characterization methods. Protein concentration determination. Protein concentration was determined by absorbance at 220nm or 280nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1AU=1mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm (Phenomenex, Part No. CH0-9229) connected to a Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1M NaCl, 12.5mM Na2HPO4, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2μm PES filter into a clean glass media bottle).25μL of sample were loaded on the column and the analysis was performed at 25 °C with a flow rate of 1mL/min for 20min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. Analytical Anion Exchange Chromatography. For the analysis an HPLC Dionex Ultimate 3000 and a TSKgel DEAE-3SW column 7.5mm ID x 7.5cm, 10μm was used. Chromatography was performed at 25 °C.10% Trifluoroethanol, 45% Acetonitrile in water was used as a blank solution. The column was equilibrated with 20mM Na₂HPO₄/ KH₂PO₄ ( Na₂HPO₄: Fisher Chemical, Lot# 188298, PN# S374-500, KH₂PO₄: Fisher Chemical, Lot# 187270, PN# P285-500), pH 6 at 1 mL/min for 10 min.30μL of sample were loaded on the column. Bound silk polypeptides were eluted with a linear gradient of 500mM NaCl. All solutions were made in LCMS water: Fisher Chemical, Lot# 216650, PN# W5-4. Collected data were analyzed with XCalibur^TM Software. Isoelectric Point determination of silk. To determine the isoelectric point of the new silk compositions Isoelectric Focusing gels were used. These separate proteins based on their net charge and not their molecular weight. For the analysis, a BIO-RAD Criterion Precast Gels was used, IEF standards pI 4.45- 9.6. Silk protein samples from new silk compositions were mixed with IEF Sample Buffer (make sure that you have at least 5% v/v glycerol in the final mix). The mixtures were loaded on a Criterion Precast Gel. For the electrophoresis a 1x IEF Anode Buffer and 1x IEF Cathode Buffer were used. The running conditions for the electrophoresis were: 100 V constant for 60 min, 250 V constant for 60 min and 500 V constant for 30min. After the electrophoresis was complete proteins were fixed on the gel with a solution of 40% v/v Methanol (Sigma Aldrich, Methanol ACS reagent >99.8%, 179337-4L-Pb,Source SHBN0806, Pcode 1003210445), 10% v/v Acetic acid, for 30 min to overnight at room temperature with rocking. LC/MS analysis of polypeptides. Samples were stored at 4 °C until used for analysis. For each sample, an aliquot was taken and mixed with an equal volume of 6 M guanidine hydrochloride (GuHCl) in a new tube. From that mix, an aliquot was taken again to create 120-fold and 240-fold further dilutions for determining protein concentrations using the BCA assay. Using the concentrations determined above, samples were diluted to 20μg/μL with 6 M GuHCl. An aliquot of 1,000 μg total protein was transferred to a new tube.50 mM dithiothreitol (DTT) was added to a final concentration of 5 mM and the samples were incubated at 60 °C for 30 minutes. After a brief equilibration period to room temperature, 100 mM iodoacetamide (IAM) was added to a final concentration of 10 mM and the samples were incubated at room temperature in the dark for 30 minutes. The IAM reaction was quenched by the addition of 50 mM DTT to a final concentration of 5 mM DTT, followed by a further incubation at room temperature for 30 minutes. Three aliquots corresponding to 100 μg of total protein were taken in separate tubes and diluted in PBS to get a final concentration of 0.2 M GuHCl. Samples were then treated with enzyme at a protease to protein ratio of 1:50 (2 μg of each protease) overnight at either room temperature (chymotrypsin) or 37 °C (trypsin/Lys-C and Glu-C). The protease reactions were quenched by the addition of TFA to a final concentration of 1% (v/v). Samples were centrifuged for 10 minutes at 14,000 rpm and supernatant was transferred to HPLC autosampler vials for LC-MS analysis. LC Column: C18 column (100 μm x 150 mm, 3 μm) Mobile Phase A: Water 0.1% formic acid Mobile Phase B: Acetonitrile 0.1% formic acid Flow Rate: 600 nL/min (micro pump) and 15 μL/min (loading pump) Chromatographic time: 60 minutes Elution Gradient: 7% B (0 to 3.3 min); 7% to 35% B (3.3 to 35 min); 35% to 95% B (35-37 min); 95% to 80% B (37-39 min); 80% B (39-41 min); 80% to 7% B (41 to 44 min); 7% B (44 to 60 min) Injection volume: 4 μL Acquisition for full MS ranges from 350 to 1600 m/z. The MS method is based on data-dependent acquisition (DDA) for the top 10 ions with an isolation window of 3.0 m/z and a normalized collision energy of 26. Data was acquired using Thermo XcaliburTM Software. Data analysis was performed using Thermo Proteome DiscovererTM Software. To unequivocally assign a specific protein from the identified peptides, a minimum of 2 unique peptides per protein are required upon searching against SwissProt database. Gel Staining methods. Silver Staining SDS and IEF polyacrylamide gels were stained using ProteoSilver Silver Stain Kit following the manufacturer’s instructions. Briefly, gels were immersed in fixing solution (50% v/v Ethanol, 10% Glacial Acetic Acid), washed with water, sensitizer solution, silver solution and developer solution. Gel band development was terminated with ProteoSilver Stop Solution. Self Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50mM CH₃COONa pH=5. Each reaction was done in a final volume of 200 μL. Total silk protein concentration was 5 mg/mL. First the buffer of 50mM CH3COONa pH=5, 35% v/v 2- propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully so as to not create any bubbles. Absorbance was recorded at 550 nm for 16-24 h (depending on the sample). Recorded values were exported in Excel files for storage and further analysis. Table 80. Detailed composition of all AS products generated herein. The composition of each product is given in % per mass (mg/mL).

Example 34: Low and Mid Molecular Weight Silk Preparation Fibroin isolation Fibroin isolation requires separation of sericin from raw B. mori silk fibers. This separation was carried out in a single stage and facilitated in a solid extraction operation. The unit was comprised of an atmospheric vessel enclosing a perforated drum which rotates on a horizontal axis. Before loading the raw silk fibers into the rotating drum via a sealable access port, silk cocoons were packed loosely into permeable mesh bags. This primary containment minimizes product loss, protects the equipment by preventing rogue silk strands from entangling with rotating components in the vessel, and protects the drain lines from plugging with solids that would otherwise escape from the drum during processing. The vessel was filled with extraction solvent comprised of 0.7% - 0.95% wt. (typically 0.94% wt.) sodium carbonate in water to partially submerge the perforated drum. This solvent composition was shown effective at dissolving and stabilizing sericin in solution. The cocoon/solvent ratio was 0.040 kg/kg – 0.070 kg/kg (typically 0.042 kg/kg). An electric heater located at the base of the vessel was used to maintain temperature of the extraction solvent in the range of 94.5° C – 97° C. Maintaining the extraction solvent at elevated temperature drives sericin solvation. Secondarily, the elevated temperature thermally cleaves fibroin chains to reduce average molecular weight of the protein population. The rotating drum turned periodically throughout a 30-minute isothermal phase of the extraction. This action serves to expose all fiber surfaces to the extraction solvent. Rinsing with copious hot water followed. The vessel was filled with non-potable water to partially submerge the perforated drum. Rinse water temperature was maintained in the range of 55° C – 65° C for 20 minutes with intermittent drum rotation, then the rinse water was drained to waste. This was repeated two additional times. Once rinsed, the drum rotated at high speed to remove water retained in the cocoons by centrifugal action. Damp fibroin with moisture content from 15% - 65% wt. (average 46.74%) was then manually removed from the washer and distributed evenly onto perforated trays. The residual moisture was driven off the fibroin by storage in a dryer with internal temperature maintained at 55° C - 60° C until moisture content of the material was less than 1% of the total mass. Extraction efficacy was verified by measuring the change in mass of the dry material before and after processing in the extraction unit. Typically, the amount of sericin removed from the cocoons is 30-36% wt. of the total mass of the raw cocoons. The composition of the raw cocoons was characterized by LCMS. The method screened for chorion, fibrohexamerin (P25), heavy chain fibroin, light chain fibroin, sericin, and trypsin inhibitor. Using LCMS, sericin concentration in raw cocoons was determined to be ~35.27% wt. Sericin was undetectable in fibroin after processing in the extraction unit. This result suggests that the sericin extraction method is effective, and the fraction of sericin detected in the raw cocoons corresponds well with the observed mass loss of the cocoons in the field. Change in the relative abundance of heavy chain fibroin versus light chain fibroin in the isolated fibroin was also observed. In raw cocoons, the ratio of heavy chain fibroin to light chain fibroin was determined to be 1.13 kg/kg. Following sericin extraction, the ratio was in the range of 0.4- 0.8 kg/kg. This reduction in the relative abundance of heavy chain fibroin suggests efficacy of the extraction process in thermally facilitated cleaving of the fibroin chains prior to solvation and modification. Fibroin solvation and modification Control over the solubilization and modification of fibroin was achieved by dispersing the solid protein into a solvent and thermally treating the mixture at variable time and temperature. Typically, a 9.3 M lithium bromide solution in water was used as a solvent. The solvent was prepared in a vessel with or without baffles. The solution was blended to uniformity in the vessel using a center-mounted agitator with stacked 45° pitched blade turbines. Heat transfer oil circulates through the vessel jacket to stabilize bulk fluid temperature at the required reaction temperature while the solvent mixes. Typically, the reaction temperature was stabilized in the ranges of 100° C – 103° C (103° C target) or 122° C - 125° C (125° C target). Fibroin was loaded into the vessel through an access port in the vessel head once the solvent reached the required reaction temperature. The mass ratio of fibroin to solvent was typically 0.16 kg/kg. Since the solvent density significantly exceeds the density of the dried fibroin, achieving full dispersion of the fibroin into the solvent is nontrivial. Substantial downward force was applied to the floating protein mat to fully submerge the material and clear the headspace for additional material to be added. Once the headspace was cleared, agitation was briefly employed to disperse the wetted silk mat before addition is continued. Loading the vessel with the full mass of fibroin occurs over the course of 40-60 minutes, during which time reaction temperature is maintained in the vessel. The reaction time begins after the fibroin addition is completed. Agitation was carried out over the full course of the reaction period. Reaction time varied depending on the desired properties of the resulting solution. To produce Activated Silk^TM 33B (Mid MW Activated Silk^TM), the reaction was carried out for 0 – 60 minutes with working fluid temperature held at 100° C – 103° C. Figure 76 displays the typical evolution of the average molecular weight of the solubilized fibroin as a function of reaction time for Activated Silk^TM 33B. To produce Activated Silk^TM 27P (Low MW Activated Silk^TM), the reaction was carried out for 40 – 420 min with temperature held at 122° C – 125° C. Figure 77 displays the typical evolution of the average molecular weight of the solubilized fibroin as a function of reaction time for Activated Silk^TM 27P. The contents of the vessel are subsequently cooled. Cooling was accomplished by either of two methods. In one method, cooling was carried out by immediate removal of the solution from the vessel, dividing the solution into small volumes, and storing the containers in a refrigerator held at 4° C. In another method, cooling was carried out in place by recirculating chilled heat transfer oil through the vessel jacket. If cooling using a jacketed vessel, the temperature may be reduced to below 60° C within 70 minutes of the reaction period elapsing. Cooling to room temperature from 60° C may be carried out more slowly by environmental radiation or by forced cooling. When using forced cooling, the solution can be brought to room temperature within 3 hours. Activated Silk^TM Purification The cooled reaction mixture is a viscous liquid comprised of water, stabilizing salt (typically LiBr), fibroin, and miscellaneous undissolved organic solids. Fibroin must be isolated from this mixture. Purification occurs through three filtration stages. First, the reaction mixture underwent dead-end filtration through a needle felt polypropylene filter media with nominal particle size rejection in the range of 1 µm – 200 µm to remove relatively large undissolved contaminants. The filtered reaction mixture was transferred through the filtration media to a holding vessel with or without baffles, which was pre- charged with some volume of reverse osmosis/de-ionized (RODI) water. The volume of water charged to the holding vessel was determined by multiplication of the reaction mixture volume against a water-to-reaction mixture volumetric ratio. This ratio ranges from 1 – 7 L/L depending on the desired product and required downstream processing conditions. The reaction mixture was blended to uniformity with the dilution water using a center- mounted agitator with stacked 45° pitched blade turbines or a propeller. Chilled propylene glycol circulates through the vessel jacket to cool the diluted mixture if the diluted material was stored for greater than 24 hours. Agitation for blending was limited to the bare minimum to achieve homogeneity, as excessive or prolonged shear on the fluid increases risk of product loss due to precipitation or foaming. The diluted reaction mixture underwent additional dead-end filtration through either a melt-blown and spun-bonded pleated poly propylene media with nominal 0.2 µm rejection or a resin bonded cellulose/diatomaceous earth lenticular media with absolute 2.5 µm rejection to reduce solution turbidity below a desired threshold. The diluted reaction mixture was transferred through the filtration media to a tangential flow filtration (TFF) unit outfitted with a jacketed retentate vessel, a rotary lobe pump, 10 kDa molecular weight cutoff hollow fiber ultrafiltration membranes, and an automatically controlled backpressure valve used to stabilize transmembrane pressure (TMP) during processing. TMP is defined as the average internal pressure of the TFF unit minus the permeate line pressure. The diluted reaction mixture recirculated between the retentate vessel and the membrane bank via the lobe pump and backpressure valve. The pump operated to maintain a constant recirculation flowrate, typically in the range of 200 – 500 L/min depending on application. The backpressure valve was actuated to maintain TMP in the range of 7 – 18 psig depending on application. Chilled or heated propylene glycol or water was circulated through the retentate vessel to maintain working fluid temperature between 20° C and 35° C depending on application. Operating under these conditions drives permeation of water, LiBr, and smaller fibroin fragments through the membrane selective layers to waste. The majority of the dissolved fibroin was retained by the membranes. The TFF operation began diafiltration, where volume was maintained in the retentate vessel by backfilling with RODI water during as volume was lost to membrane permeate. Diafiltration conditions were maintained until the conductivity of the permeate dips below a desired threshold, typically 10 - 50 µS/cm. Critically, LiBr concentration must be below 150 ppm. Diafiltration ceases once this condition is satisfied, at which point RODI water flows to the system stops and the working fluid is allowed to concentrate as permeation continues under maintained TMP and flow conditions. Protein concentration was monitored over the course of the concentration phase of operation. Concentration conditions were maintained until the protein concentration was within the range of 5 – 17% wt, depending on application. Total residence time in the TFF unit ranged from 12 – 35 hours depending on application. The purified Activated Silk^TM solution was drained from the TFF unit and stored in either HDPE carboys or stainless-steel totes. The Activated Silk^TM solution was stored at 4° C to maximize shelf life. Conclusions Process development has resulted in product yield improvements. Relative to the existing processes, yield was increased by ~100x for Activated Silk^TM 27P and ~40x for Activated Silk^TM 33B when the purification train was initially scaled up, then further increased by 1.75x for Activated Silk^TM 27P and 2.9x for Activated Silk^TM 33B when the processing techniques matured further. Additionally, process development has resulted in significant quality improvements exemplified by reduced variation in critical quality parameters, specifically in measurement of weight average molecular weight and dispersity characteristics of the protein population in the final product. In reference to previous processes, the first instance of scaleup work resulted in a 58% reduction in the standard deviation of molecular weight measurements and a 31% reduction in the standard deviation of dispersity measurements for Activated Silk^TM 27P. In reference to previous processes, the first instance of scaleup work also resulted in a 29% reduction in the standard deviation of molecular weight measurements and a 59% reduction in the standard deviation of dispersity measurements for Activated Silk^TM 33B. In reference to previous processes, the second instance of scaleup work resulted in a 64% reduction in the standard deviation of molecular weight measurements and a 12% reduction in the standard deviation of dispersity measurements for Activated Silk^TM 27P. In reference to previous processes, the second instance of scaleup work also resulted in a 75% reduction in the standard deviation of molecular weight measurements and a 70% reduction in the standard deviation of dispersity measurements for Activated Silk^TM 33B. Example 35: High Molecular Weight Silk Preparation Fibroin isolation Fibroin isolation requires separation of sericin from raw B. mori silk fibers. This separation was carried out in a single stage and facilitated in a solid extraction operation. The unit was comprised of an atmospheric vessel enclosing a perforated drum which rotated on a horizontal axis. Before loading the raw silk fibers into the rotating drum via a sealable access port, silk cocoons were packed loosely into permeable mesh bags. This primary containment minimized product loss, protected the equipment by preventing rogue silk strands from entangling with rotating components in the vessel, and protected the drain lines from plugging with solids that would otherwise escape from the drum during processing. The vessel filled with extraction solvent comprised of 0.705 % sodium carbonate in water to partially submerge the perforated drum. This solvent composition has been shown effective at dissolving and stabilizing sericin in solution. The cocoon/solvent ratio was 0.068 kg/kg. An electric heater located at the base of the vessel was used to maintain temperature of the extraction solvent in the range of 94.5 °C – 97 °C. Maintaining the extraction solvent at elevated temperature drives sericin solvation. Secondarily, the elevated temperature thermally cleaves fibroin chains to reduce average molecular weight of the protein population. The rotating drum turned periodically throughout a 30-minute isothermal phase of the extraction. This action served to expose all fiber surfaces to the extraction solvent. Rinsing with copious hot water follows. The vessel was filled with non-potable water to partially submerge the perforated drum. Rinse water temperature was maintained in the range of 55 °C – 65 °C for 20 minutes with intermittent drum rotation, then the rinse water was drained to waste. This was repeated two additional times. Once rinsed, the drum rotated at high speed to remove water retained in the cocoons by centrifugal action. Damp fibroin with moisture content from 15% - 65% wt. (average 46.74%) was then manually removed from the washer and distributed evenly onto perforated trays. The residual moisture was driven off the fibroin by storage in a dryer with internal temperature maintained at 55 °C - 60 °C until moisture content of the material was less than 1% of the total mass. Fibroin solvation and modification Control over the solubilization and modification of fibroin was achieved by dispersing the solid protein into a solvent and thermally treating the mixture at variable time and temperature. A 9.3 M lithium bromide solution in water was used as a solvent. To produce High MW Activated Silk^TM, 400 mL of solvent were added to two 4 L glass beakers. The beakers were then placed into an oven set to 160 °C and allowed to heat until the solvent temperature is 100 °C ± 4 °C. Once the solvent temperature was stabilized, 100 g of dried fibroin was added to each beaker and fully wetted with solvent by manual agitation with a stainless-steel spatula. The beakers were then placed back into the oven set to 160 °C and allowed to remain in the oven for 15 – 60 min, depending on the required product characteristics. Solvent temperature was continuously monitored to ensure that the solvent temperature was maintained at 100 °C ± 5 °C for the duration of the reaction period. The beakers were removed from the oven after the required reaction period. The beakers were allowed to cool for 30 - 60 min at ambient temperature. Undissolved solids in the beakers were removed. The volume of remaining liquid in the beakers was then measured into a sealed container and stored in a refrigerator at 4 °C. Activated Silk^TM Purification The cooled reaction mixture was a viscous liquid comprised of water, LiBr, fibroin, and minute undissolved organic solids. Fibroin must be isolated from this mixture. First, the reaction mixture was diluted into reverse-osmosis/deionized (RODI) water. The diluted mixture was brought infirmity by manual agitation of the dilution vessel, which was typically a sealable 5 gal BPA-free carboy. The volumetric ratio of reaction mixture to RODI water was 0.0562 mL/mL. The diluted reaction mixture then underwent dead-end filtration through a pleated glass fleece filter media with absolute 0.65 μm particle size rejection to remove minute undissolved solids and reduce solution turbidity. The diluted reaction mixture was transferred through the filtration media to a tangential flow filtration (TFF) unit outfitted with a retentate vessel (typically a sealable 50 L polypropylene carboy), a variable speed diaphragm pump, 10 kDa molecular weight cutoff hollow fiber ultrafiltration membranes, and a manually actuated backpressure valve used to stabilize transmembrane pressure (TMP) during processing. TMP was defined as the average internal pressure of the TFF unit minus the permeate line pressure. The diluted reaction mixture recirculated between the retentate vessel and the membrane bank via the diaphragm pump and backpressure valve. The pump was manually operated to maintain a constant 10 psi pressure drop across the membrane module. The backpressure valve was manually actuated to maintain TMP in the at approximately 35 psi. Operating under these conditions drives permeation of water, LiBr, and smaller fibroin fragments through the membrane selective layers to waste. The majority of the dissolved fibroin was retained by the membranes. The TFF operation began diafiltration, where volume was maintained in the retentate vessel by backfilling with RODI water during as volume was lost to membrane permeate. Diafiltration conditions were maintained until the conductivity of the permeate dipped below a desired threshold, typically 10 - 50 μS/cm. Critically, LiBr concentration must be below 150 ppm. Diafiltration ceases once this condition is satisfied, at which point RODI water flow to the system stops and the working fluid is allowed to concentrate as permeation continues under maintained TMP and flow conditions. Protein concentration was monitored over the course of the concentration phase of operation. Concentration conditions were maintained until the protein concentration was within the range of 5 - 7%wt. The purified Activated Silk^TM solution was drained from the TFF unit and stored in either HDPE carboys or stainless-steel totes. The Activated Silk^TM solution was stored at 4 °C to maximize shelf life. Example 36: Low and Mid Skid Silks Degree of Amino Acid Modifications. Low and Mid Skid silk polypeptide compositions described herein are never produced before compositions of silk-derived and modified polypeptides that when isolated displayed a wide range of behaviors, from extreme self-assembly to superb solubility and stability over time in various buffers and various average molecular weights and polydispersities. These novel silk- derived polypeptide compositions contain unique modified amino acids that result from unique silk processing method and scale. The tight controls around temperature, silk concentration, salt concentrations, physical agitation and purification allow for tuning at each step of the process the unique peptide compositions in the silk species to design for specific performance criteria. Some of constituent polypeptide compositions display biological activity and could be used as therapeutic candidates. Silk is a versatile material that can be used in many applications from development of implantable medical devices to the development of soluble polypeptide formulations of medicinal value. A major challenge with silk polypeptides in solution is their tendency to self-assemble and aggregate, making the control of their solubility very difficult. Also, the kinetics of gel/film formation cannot be controlled in a predictable way. The novel silk peptide compositions described herein contain populations of peptides that allow for the control of their properties and allow for the development products with predictable and desired properties. Development of Low and Mid Skid silk/modified polypeptide compositions. Activated silk contains a collection of many polypeptides with different properties. Silk has been characterized mostly based on its molecular weight and polydispersity. Until now, no mixture of silk polypeptides has been characterized or has been generated. A unique large-scale process was used to generate compositions of silk polypeptides. Low/Mid skid silks began their process to remove sericin using sodium carbonate at specific silk mass, sodium carbonate, and water ratios. Multiple different temperature washing cycles 100 °C and 60 °C and agitation was also key in producing the specific natural and modified compositions. The silk was then dried to remove water at a specific temperature that maintained the silk composition. Next the silk was dissolved in a high concentration of Lithium Bromide at 103 °C and 125 °C for 1 and 6 hours, respectively. The time and temperature allow for fine tuning the degree of post translational modifications that give the unique polypeptide compositions. The silk was then purified to remove Lithium Bromide and concentrate the silk. Generation of Low and Mid Skid silk/modified polypeptide compositions. Silk was washed to remove sericin at 100 °C and 60 °C with sodium carbonate and then dried at 60 °C. The silk was then dissolved in 9.3 M Lithium Bromide at 103 °C for 1 hour for Mid silk and 9.3 M Lithium Bromide at 125 °C for 6 hours for Low silk. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk was then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops was tightly controlled for temperature, time, concentrations, agitation, and shear. Our silk preparations have unique modifications depending on the production method. The dissolution of degummed silk cocoons was performed in high concentration of chaotropic salts (9M LiBr) and at very high temperatures that exceed 100 °C (see previous sections). The unique thermal treatment that occurs during the production method described herein, promotes the deamidation of Asparagine and Glutamine residues and the oxidation of Methionines. The deamidation of Asparagine and Glutamine residues and the oxidation of Methionines is referred to as “modifications” from now on. To determine the degree of amino acid modification during the various silk preparation methods LC/MS approaches were used (see LC/MS analysis of polypeptides for more details). When Low Skid Silk was compared with Mid Skid silk produced, it was found that Low Skid silk was more modified than Mid Skid silk (Figs.79A- 79C, Table 81). When silk produced was lyophilized it retained the same modification trend; lyophilized Low Skid silk was more modified than lyophilize Mid Skid silk (Figs.80A-80B, Table 82). Low Skid silk produced in one facility unique and less modified than the Low Skid silk produced in another (Figs.80A- 80B, Table 83). When silk was produced using a benchtop setup, the resulting silk preparation was less modified compared to its Skid counterpart (Fig.82, comparing Mid Skid silk with Mid Benchtop silk). LC/MS analysis of polypeptides. Materials Reagents ● Guanidine hydrochloride (GuHCl) (Sigma cat# G3272-1KG) ● Dithiothreitol (DTT) (ThermoFisher cat# 20290) ● Iodoacetamide (IAM) (Sigma cat# I1149-5G) ● HPLC-grade water (FisherChemical cat# W5-4) ● Acetonitrile (ACN) (FisherChemical cat# A955-4) ● Formic acid (FA) (FisherChemical cat# A117-10X1AMP) ● Trifluoroacetic acid (TFA) (FisherChemical cat# A116-10X1AMP) ● Sodium acetate (Sigma cat# S5636-250G) Proteases ● Trypsin/Lys-C mix (Promega cat# V5073) ● Chymotrypsin (Promega cat# V1061) ● Glu-C (Promega cat# V1651) Solutions ● 6 M GuHCl ● 50 mM DTT (10X) ● 100 mM IAM (10X) ● 50 mM sodium acetate Methods Denaturation, Reduction and Alkylation Samples were stored at 4 °C until used for analysis. For each sample, an aliquot was taken and mixed with an equal volume of 6 M guanidine hydrochloride (GuHCl) in a new tube.50 mM dithiothreitol (DTT) was added to a final concentration of 5 mM and the samples were incubated at 60 °C for 30 minutes. After a brief equilibration period to room temperature, 100 mM iodoacetamide (IAM) was added to a final concentration of 10 mM and the samples were incubated at room temperature in the dark for 30 minutes. The IAM reaction was quenched by the addition of 50 mM DTT to a final concentration of 5 mM DTT. The samples were diluted in 50 mM sodium acetate to get a final concentration of 0.18 M GuHCl. Protease digestion Using the sample concentrations provided, 3 aliquots corresponding to 30 μg of total protein were taken in separate tubes. Samples were then treated with enzymes at a protease to protein ratio of 1:30 (1 μg of each protease) overnight at either room temperature (chymotrypsin) or 37 °C (trypsin/Lys-C and Glu-C). The aliquots treated with trypsin/Lys-C and Glu-C were boosted with the same amount of enzyme and incubated at 37 °C for 3 hours the next day. The protease reactions were quenched by the addition of TFA to a final concentration of 1% (v/v). Samples were centrifuged for 10 minutes at 14,000 rpm and supernatant was transferred to HPLC autosampler vials for LC-MS analysis. LC Conditions Column: C18 column (100 μm x 200 mm, 3 μm) Mobile Phase A: Water 0.1% formic acid Mobile Phase B: Acetonitrile 0.1% formic acid Flow Rate: 300 nL/min (micro pump) and 15 μL/min (loading pump) Chromatographic time: 60 minutes Elution Gradient: 14% B (0 to 3.3 min); 14% to 30% B (3.3 to 35 min); 30% to 95% B (35- 37 min); 95% to 80% B (37-39 min); 80% B (39-41 min); 80% to 14% B (41 to 44 min); 14% B (44 to 60 min) Injection amount: 2 ug MS Conditions Acquisition for full MS ranges from 350 to 1600 m/z. The MS method is based on data- dependent acquisition(DDA) for the top 10 ions with an isolation window of 3.0 m/z and a normalized collision energy of 27. Data Acquisition and Analysis Data was acquired using Thermo Xcalibur^TM Software. Data analysis was performed using Thermo Proteome Discoverer^TM Software. In order to unequivocally assign a specific protein from the identified peptides, a minimum of 2 unique peptides per protein are required upon searching against Bombyx mori database. For each modification site, all the peptides containing that amino acid were categorized into modified vs unmodified. The modification percentage is then calculated using the formula below:

Table 81. Percentage of amino acid modifications in Low and Mid Skid silk produced in the facility in Walpole. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Fibroin Heavy Chain LS M

Fibroin Light Chain LS MS

Fibrohexamerin (p25) L M

Table 82. Percentage of amino acid modifications in Low and Mid Skid silk produced in the facility in Walpole and lyophilized. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Fibroin Heavy Chain

Fibroin Light Chain L M

Table 83. Percentage of amino acid modifications in Low Skid silk produced in the facility in Walpole and Medford. N are Asparagines and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Fibroin Heavy Chain L L

Fibroin Light Chain L L

Table 84. Percentage of amino acid modifications in Mid silk produced in Skid and Benchtop scale. N are Asparagines that become aspartic acid and Q are Glutamines that become deamidated. M corresponds to Methionies that become oxidized. Fibroin Heavy Chain M M

Calculation of the percentage of amino acid modification per location along the amino acid sequence of each protein chain. To determine the percentage of modified amino acids within the sequences of individual protein chains in the silk preparations, LC/MS analysis was employed. Through this analytical method, it was not only discerned the sequence of all peptides present in the solution but also quantified their respective concentrations. LC/MS methodology possesses the capability to pinpoint amino acid modifications at specific positions within these sequences, a phenomenon induced by the production techniques. Upon successfully identifying and quantifying all the peptides within the mixture, they were aligned with the protein sequences present in the silk cocoons. This alignment process allowed for the ascertainment of the origin of each peptide along the polypeptide chain of fibroin heavy and light chains, as well as fibrohexamerin (p25). Consequently, the exact positions of amino acids were pinpointed on these polypeptide chains. To calculate the percentage of modified amino acids at specific locations, all peptides containing these amino acids were quantified, both modified and unmodified. The calculation involved dividing the quantity of peptides containing modified amino acids by the total quantity of peptides containing those particular amino acids (modified and unmodified) and then multiplying the result by 100. This yielded the percentage of modified amino acids at the designated location. Refer to Fig.83. Example 37: Low Skid Silk/Modified Polypeptide Compositions Isolated by Charge and Size Properties Described herein is a novel method to generate compositions of polypeptide that are derived from B. mori silkworm cocoons and comprise of natural and modified polypeptides. This novel composition is called Low Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at 125 ˚C for 6 hours to achieve the compositions of Low Skid silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Low Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties. Low Skid silk/modified polypeptide composition does not self-assemble at 5 mg/mL. Low Skid silk/modified polypeptide composition comprises of a variety of populations of silk/modified polypeptides; distinct populations were isolated based on charge and size, by fractionating Low Skid silk/modified polypeptides by anion exchange chromatography and size exclusion chromatography. A high-resolution separation of five negatively-charged silk compositions was achieved– AS77, AS78, AS79, AS80, and AS81. These silk compositions differ from one another by their average size, when AS77 is the largest, and AS81 is the smallest. These silk compositions do not self-assemble under conditions that promote self- assembly at 5 mg/mL. The Low Skid silk/modified polypeptide compositions described in this invention are novel compositions of silk and modified polypeptides composed of a variety of silk polypeptide populations, generated by the exclusive treatment method of natural silk produced by B. mori. These silk compositions contain modified amino acid sequences that result from silk processing method and scale. The tight controls over temperature, silk concentration, buffers and salt concentrations, physical agitation, and purification allow for the precise development of silk compositions with a variety of performance criteria. Isolation of these populations by charge and size reveals new characteristics, like high solubility and stability in solution over time in these populations. The purification method allows for the isolation of silk/modified polypeptide compositions that display biological activities and could be used for therapeutic purposes. Silk is a complex natural biomaterial that has the potential to be utilized in various applications such as the development of implantable medical devices, and the development of soluble polypeptide compositions of medical value. Additionally, it was demonstrated that silk peptides have anti-genotoxic effects. However, silk, in its natural form, is not soluble, and silk polypeptide compositions, without the proper processing, display poor solubility in solution and tend to self-assemble and aggregate over time. The kinetics of this self-assembly is unpredictable, and highly depends on the composition of the silk polypeptides/modified composition. Novel silk/modified polypeptide compositions were produced and the silk/modified polypeptide compositions isolated specific populations within these compositions. The isolation process allows for the control of the properties of the silk compositions and development of products with predictable and desired characteristics. Generation of Low Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100 ˚C and 60 ˚C with sodium carbonate and then dried at 60 ˚C. The silk is then dissolved in 9.3 M Lithium Bromide at 125 ˚C for 6 hours. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Low Skid/modified polypeptide compositions Isolation of the AS77-AS81 silk/modified polypeptide composition component of Low Skid silk/modified polypeptide composition. To isolate AS77-AS81 Low Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-eluate (figure 84, 85A and 85B). Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH=8.0. The silk was centrifuged and filtered before loading to the Q-Sepharose column, to remove any preformed aggregates. The silk compositions were loaded onto the Q-Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl2). The eluted fractions were pulled together and are referred to as the Q- elution fraction. The Q-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Figs.84, 85A, 85B). Low Skid silk preparation solutions have a characteristic yellow hue. The Q-elution fraction has a strong yellow hue, while the flowthrough fraction is transparent, and tends to self-assemble very quickly. The Q-elution silk compositions that are fractionated by size exclusion also had a yellow hue. When silk formulations AS77-AS81 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average Mw, and a different Polydispersity (PDI) value (Figs.86A-86B, Table 86). In general, AS77 has the highest Mw (55714 Da), while AS81 has the lowest Mw (28750 Da). The PDI values display a differential change as well. The PDI value of AS77 is relatively low (1.1836), and AS81 is higher (1.3648) (Figs.86A-86B, Table 86). Unfractionated Low Skid silk has an average Mw of ~19500, indicating that most of the peptide population tends to have lower molecular weight than fractions AS77-AS81. The polydispersity of unfractionated Low Skid silk is ~2.2 – significantly higher than the values of fractions AS77-AS81. This indicated that the unfractionated Low Skid silk is composed of a much diverse peptide population compared to fractions AS77-AS81. AS77-AS81 silk compositions demonstrate relative uniformity by dynamic light scattering and show gradual particle size distribution. In dynamic light scattering analysis (Figure 89A and 89B, Table 85), AS77-AS81 demonstrated relatively uniform, though broad, peaks where AS77 has the largest Z-average (17.16 nm), then AS78 (15.14 nm), and so on (Table 85), demonstrating the efficiency of the fractionation by size of the Q-elution fraction. Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self-assembly assay and data derived from it. To study the stability of silk/modified peptide compositions in solution, Self-Assembly assays at a concentration of 5 mg/mL were performed. The absorbance at 550 nm curves of the self-assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is:

A_max is the maximum density of the gel formed k is the Self-Assembly Rate Factor (SARF) t_0.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve

(see Fig. MA the red dotted lines for a better demonstration of how these factors from the SelfAssembly experiments were calculated)

Another parameter introduced to characterize the propensity of silk to form gels is the SelfAssembly Factor (F_SAF) which is:

Using the experimental data from the Self-Assembly assays that were performed with the various novel isolated silk polypeptides, these parameters were calculated and used to dissect their properties (Figs. 88A-88B). Four parameters were focused on. collectively referred to as Self-Assembly kinetic factors; the Self-Assembly Rate Factor (SARF), Amm, t0.5, and the Self-Assembly Factor (SAF) (Figs. 88A-88B). The SARF shows how fast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed; Amm shows how dense is the gel that is formed after self-assembly is complete, t0.5 shows how long it takes for the self-assembly reaction to reach the point where gel density is and SAF

shows the propensity of silk to self-assemble (Figs. 88A-88B).

AS77-AS81 silk compositions do not self-assemble.

Self-assembly assays revealed that Low Skid silk/modified peptide compositions do not self-assemble under the experimental system conditions (Figure 89A). No self-assembly occurred after 24 hours, and no self-assembly was detected even 12 days post-assay (Figure 89B). Mid Skid/modified peptide compositions was used as a positive control and shows fast self-assembly kinetics (Figs. 88A-88B).

Materials and Methods used for the generation and characterization of AS77-AS81. Anion exchange chromatography of silk.

Low Skid silk was provided at a concentration of 60 mg/mL. 50 mM Tris, pH=8.0 buffer was added to the Low Skid silk, and the silk was centrifuged at 16000 rpm (rotor JA-18, Beckman coulter, average of 28100 xg), at 4 °C, for 30 min to separate formed aggregates from soluble silk. The supernatant was collected and filtered through a 0.22 pm PES filter. For silk fractionation, Q-Sepharose prepacked columns connected to an AKTA pure 25 L or HiPrep Q FF 16/10 20 mL Column, or HiTrap™ Capto™ Q 1 mL column was used. All buffers used were filtered through a 0.22 μm PES filter and degassed with sonication. Centrifuged and filtered Low Skid silk was loaded on 5 x 5 mL HiTrap Q HP columns washed with 10 column volumes of 50 mM Tris pH=8.0, 10 column volumes of 50 mM Tris pH=8.0, 500 mM CaCl₂ and finally 10 column volumes of 50 mM Tris pH=8.0.170 mL of centrifuged Low Skid silk were loaded on the column with a flow rate of 5 mL/min. The flow-through was collected. The column was washed with 50 mM Tris pH=8.0 until the absorbance at 280 nm [A₂₈₀] got to 100 AU. Bound protein was eluted in one step with 50 mM Tris pH=8.0, 500 mM CaCl₂ and all fractions with absorbance [A₂₈₀] >500AU were pooled together. The Q-elution fraction (the eluate) was then used for further fractionation by size exclusion chromatography. Size Exclusion Chromatography of Silk. The Low Skid silk eluate fraction of the Q-Sepharose anion exchange chromatography (Q-elution) was the starting material for size exclusion chromatography. The eluate was loaded onto a HiLoad 26/600 Superdex 200 pg gel filtration column for fractionation, using the AKTA Pure 25L system. All buffers used during fractionation were filtered through 0.22 µm PES filter as well and were degassed. The Low Skid silk was loaded on the Superdex 200 gel filtration column, and was run with 50 mM Tris, 200 mM CaCl₂, pH=8.0, to fractionate the Q-elution Low Skid silk. The eluted silk compositions were collected in 10 ml fractions. Fractions 6-10 (AS77, AS78, AS79, AS80, AS81) were collected, and have relatively narrow range of molecular weight. The fractions were placed in 3.5 kDa cutoff dialysis bags, and were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da. Then, fractions in the dialysis bags were immersed in 160X volumes of 50 mM Tris pH=8.0 overnight, and then were immersed in a new batch of 160X volume of 50 mM Tris pH=8.0. Samples were kept at 4˚C until they were used. Analytical/Protein Characterization methods. Protein concentration determination. Protein concentration was determined by absorbance at 220 nm or 280 nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1 AU=1 mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analytical Size Exclusion Chromatography is performed as described in detail in the document EMED-QCP-SILK1-002. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm connected to an Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1 M NaCl, 12.5 mM Na2HPO4, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2 μm PES filter into a clean glass media bottle).25 μL of sample were loaded on the column and the analysis was performed at 25 °C with a flow rate of 1 mL/min for 20 min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. SDS polyacrylamide gel. Low Skid silk fractions were uploaded onto a Mini-Protean TGX precast gel, 4-20%, with a protein marker Trident Prestained Protein Ladder for molecular weight reference. The SDS polyacrylamide gel was stained using ReadyBlue ^ Protein stain gel. Gels were immersed in ReadyBlue™ solution for 1 h, then destained with DI/RO water. Self-Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50 mM CH₃COONa pH=5. Each reaction was done in a final volume of 200 μL. Total silk protein concentration was 5 mg/mL. First the buffer of 50 mM CH₃COONa pH=5.0, 35% v/v 2- propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully, so as to not create any bubbles. Absorbance was recorded at 550 nm for 24 h. Recorded values were exported in Excel files for storage and further analysis. Dynamic Light Scattering analysis of silk compositions. Low Skid silk compositions were diluted to a concentration of 1 mg/mL and filtered with a 0.22 µm PES syringe filter. All measurements were performed with a Malvern Zetasizer Pro Red Label, detection angle of 173˚. The Red Label system operates with a 10 mW He-Ne laser (633 nm). The software used is ZS XPLORER version 3.2.1.11. All measurements were done with 4.2 ml polystyrol/polystyrene transparent cuvettes. samples were measured at 25˚C, with 120 sec of equilibration time. The intensity size distributions, autocorrelation, and Z- average were measured. Ta Lo pol

Table 85: Z-average of AS77-AS81 calculated by Dynamic Light Scattering. The Z- average value of each silk/modified polypeptide composition was calculated by the Zetasizer Pro. Shown here are the Z-average values of each silk composition. The abbreviation d. nm refers to the diameter in nanometers.

Table 86: Molecular weight (Mw) and Polydispersity (PDI) values of silk compositions AS77- AS81. Silk/modified polypeptide compositions AS77, AS78, AS79, AS80, and AS81 were analyzed by size exclusion chromatography (SEC) column with HPLC, and values of molecular weights (Mw) and Polydispersity (PDI) are indicated. Example 38: Low Skid Silk/Modified Polypeptide Compositions Isolated by Size Properties Described herein is a novel method to generate compositions of polypeptide that are derived from B. mori silkworm cocoons and comprise of natural and modified polypeptides. This novel composition is called Low Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at 125˚C for 6 hours to achieve the compositions of Low Skid silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Low Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties. Low Skid silk/modified polypeptide composition does not self-assemble at 5 mg/mL. Low Skid silk/modified polypeptide composition comprises of a variety of populations of silk/modified polypeptides; here distinct populations were isolated based on size, by fractionating Low Skid silk/modified polypeptides by size exclusion chromatography. A high- resolution separation of five silk compositions – AS82, AS83, AS84, AS85, and AS86 was achieved. These silk compositions differ from one another by their average size, when AS82 is the largest, and AS86 is the smallest. These silk compositions do not self-assemble under conditions that promote self-assembly at 5 mg/mL. In addition to the well-separated silk compositions, lower-molecular-weight silk compositions (AS87, AS88, AS89) were generated that are less well-resolved, but composed of significantly smaller polypeptide populations. These silk compositions self-assemble into a gel within a few days under conditions that promote self-assembly at 5 mg/mL, but not as quickly as Mid Skid silk (starting to self-assemble within 3 h). Low Skid silk/modified polypeptide compositions isolated by size properties. The Low Skid silk/modified polypeptide compositions described in this invention are novel compositions of silk and modified polypeptides composed of a variety of silk polypeptide populations, generated by the exclusive treatment method of natural silk produced by B. mori. These silk compositions contain modified amino acid sequences that result from the silk processing method and scale. The tight controls over temperature, silk concentration, buffers and salt concentrations, physical agitation, and purification allow us to precisely develop silk compositions with a variety of performance criteria. Isolation of these populations by size reveals different characteristics, like high solubility and stability in solution over time in some populations, and the tendency to self-assemble in others. the purification method allows us to isolate silk/modified polypeptide compositions that display biological activities and could be used for therapeutic purposes. Silk is a complex natural biomaterial that has the potential to be utilized in various applications such as the development of implantable medical devices, and the development of soluble polypeptide compositions of medical value. Additionally, it was demonstrated that silk peptides have anti-genotoxic effects. However, silk, in its natural form, is not soluble, and silk polypeptide compositions, without the proper processing, display poor solubility in solution and tend to self-assemble and aggregate over time. The kinetics of this self-assembly is unpredictable, and highly depends on the composition of the silk polypeptides/modified composition. Novel silk/modified polypeptide compositions were produced and specific populations were isolated within these compositions. The isolation process allows us to control the properties of the silk compositions and develop products with predictable and desired characteristics. Generation of Low Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100 °C and 60 °C with sodium carbonate and then dried at 60 °C. The silk is then dissolved in 9.3 M Lithium Bromide at 125 °C for 6 hours. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Low Skid/modified polypeptide compositions Isolation of the AS82-AS89 silk/modified polypeptide composition component of Low Skid silk/modified polypeptide composition. To isolate AS82-AS89 Low Skid silk/modified polypeptide compositions were fractioned using HiLoad 26/600 Superdex 200 pg size exclusion chromatography column (Figs.90, 91). Tris was added to the silk preparations to a final concentration of 50 mM Tris– HCl, pH=8.0. The silk was centrifuged and filtered before loading to the HiLoad 26/600 Superdex 200 pg column, to remove any preformed aggregates. The silk compositions were fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Fig.91). Low Skid silk preparation solutions have a characteristic yellow hue, and the fractionated silk compositions had a yellow hue. When silk formulations AS82-AS89 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average Mw, and a different Polydispersity (PDI) value (Fig.91, Table 88). In general, AS82 has the highest Mw (51936 Da), while AS89 has the lowest Mw (6826 Da). The PDI values display a differential change as well. The PDI value of AS82 is relatively low (1.1738), and AS89 is higher (1.3544) (Figs. 92A-92B, Table 88). AS82-AS86 silk compositions demonstrate relative uniformity by dynamic light scattering, while AS87-AS89 silk compositions contain multiple peptide populations sizes. In dynamic light scattering analysis (Zetasizer Pro, Figs.95A-5C, Table 87), AS82- AS86 demonstrated relatively uniform, though broad, peaks where AS82 has the largest Z- average (18.174 nm), then AS83 (15.659 nm), and so on (Table H). AS87, AS88, and AS89 are of lower molecular weight, and are eluted later during the chromatography, where the resolution of the Superdex 200 is not optimal and cannot resolve the peptide populations very well (the column resolution is reduced for proteins smaller than average size of ~44 kDa), as can be observed by SDS gel electrophoresis in Fig.93 (fraction 11 and on). Dynamic light scattering shows two peaks for these fractions, indicating the presence of several populations (Fig.95A). Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self-Assembly assay and data derived from it. To study the stability of silk/modified peptide compositions in solution Self-Assembly assays were performed at a concentration of 5 mg/mL. The absorbance at 550 nm curves of the self-assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is:

A_max is the maximum density of the gel formed k is the Self-Assembly Rate Factor (SARF) t_0.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve (see Fig. SA the red dotted lines for a better demonstration of how these factors from the Self- Assembly experiments were calculated) Another parameter that was introduced to characterize the propensity of silk to form gels is the Self-Assembly Factor (FSAF) which is:

Using the experimental data from the Self-Assembly assays that were performed with the various novel isolated silk polypeptides, these parameters were calculated and used to dissect their properties (Figs. 94A- 94B). Four parameters were focused on, collectively referred to as Self-Assembly kinetic factors; the Self-Assembly Rate Factor (SARF), A_max, t0.5, and the Self-Assembly Factor (SAF) (Figs. 94A- 94B). The SARF shows how ast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed: A_max shows how dense is the gel that is formed after self-assembly is complete. t0.5 show s how long it takes for the self-assembly reaction to reach the point where gel density is and SAF

shows the propensity of silk to self-assemble (Figs. 94A- 94B).

AS82-AS86 silk compositions do not self-assemble.

Self-assembly assays revealed that Low Skid silk/modified peptide compositions do not self-assemble under the experimental system conditions (Fig. 94A). No self-assembly occurred after 24 hours, and no self-assembly was detected even 18 days post-assay (Fig. 94B). Mid Skid/modified peptide compositions was used as a positive control and shows fast selfassembly kinetics (Figs. S94A- 94B).

AS87-AS89 silk compositions self-assemble within few days.

Self-assembly assays as described before, revealed that AS87-AS89 do not self- assemble within 24 hours (Fig. 94A). However, if left for an extra 4-5 days, self-assembly occurs in these silk/modified polypeptide compositions (Fig. 94B). Mid Skid/modified peptide compositions was used as a positive control and shows fast self-assembly kinetics (Figs. 94A- 94B).

Materials and Methods used for the generation and characterization of AS82-AS89.

Size Exclusion Chromatography of Silk.

The starting material, Low Skid silk at a concentration of 60 mg/mL, was provided by the manufacturing team. The Low Skid silk was transferred to 50 mM Tris, pH=8.0 buffer, and centrifuged at 16000 rpm, at 4°C, for 30 min to separate formed aggregates from soluble silk. The supernatant w as collected and filtered through a 0.22 μm PES filter. Then, the silk was loaded onto a HiLoad 26/600 Superdex 200 pg gel filtration column for fractionation, using the AKTA Pure 25 L system. All buffers used during fractionation were filtered through 0.22 pm PES filter as well and were degassed. The Low Skid silk was loaded on the Superdex 200 gel filtration column, and was run with 50 mM Tris, 200 mM CaCl₂ , pH8, to fractionate the Low Skid silk. The eluted silk compositions were collected in 10 ml fractions. Fractions 6-10 (AS82, AS83, AS84, AS85, AS86) were collected, and have relatively narrow range of molecular weight, while fractions 18-20 (AS87, AS88, AS89) have a broader molecular weight range, since these molecular sizes are outside of the HiLoad 26/600 Superdex 200 pg separation range. The fractions were placed in 3.5 kDa cutoff dialysis bags, and were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da. Then, fractions in the dialysis bags were immersed in 160X volumes of 50 mM Tris pH=8.0 overnight, and then were immersed in a new batch of 160X volume of 50 mM Tris pH=8.0. Samples were kept at 4˚C until they were used. Analytical/Protein Characterization methods. Protein concentration determination. Protein concentration was determined by absorbance at 220 nm or 280 nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1AU=1 mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analytical Size Exclusion Chromatography is performed as described in detail in the document EMED-QCP-SILK1-002. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm connected to an Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1 M NaCl, 12.5 mM Na₂HPO₄, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2 μm PES filter into a clean glass media bottle).25 μL of sample were loaded on the column and the analysis was performed at 25 °C with a flow rate of 1 mL/min for 20 min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. SDS polyacrylamide gel. Low Skid silk fractions were uploaded onto a Mini-Protean TGX precast gel, 4-20%, with a protein marker Trident Prestained Protein Ladder for molecular weight reference. The SDS polyacrylamide gel was stained using ReadyBlue ^ Protein stain gel. Gels were immersed in ReadyBlue ^ solution for 1 h, then destained with DI/RO water. Self-Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50mM CH₃COONa pH=5. Each reaction was done in a final volume of 200 μL. Total silk protein concentration was 5 mg/mL. First the buffer of 50 mM CH₃COONa pH=5, 35% v/v 2-propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully so as to not create any bubbles. Absorbance was recorded at 550 nm for 24 h. Dynamic Light Scattering analysis of silk compositions. Low Skid silk compositions were diluted to a concentration of 1 mg/mL and filtered with a 0.22 µm PES syringe filter. All measurements were performed with a Malvern Zetasizer Pro Red Label, detection angle of 173˚. The Red Label system operates with a 10 mW He-Ne laser (633 nm). The software used is ZS XPLORER version 3.2.1.11. All measurements were done with 4.2 mL polystyrol/polystyrene transparent cuvettes. samples were measured at 25 ˚C, with 120 sec of equilibration time. The intensity size distributions, autocorrelation, and Z- average were measured. Tables Lo

Table 87: Z-average of AS82-AS89 calculated by Dynamic Light Scattering. The Z- average value of each silk/modified polypeptide composition was calculated by the Zetasizer Pro. Shown here are the Z-average values of each silk composition. L

Table 88: Molecular weight (Mw) and Polydispersity (PDI) values of silk compositions AS82-AS89. Silk/modified polypeptide compositions AS82, AS83, AS84, AS85, AS86, AS87, AS88, and AS89 were analyzed by size exclusion chromatography (SEC) column with HPLC, and values of molecular weights (Mw) and Polydispersity (PDI) are indicated. Example 39: Low Skid silk/modified polypeptide compositions isolated by charge, hydrophobicity levels, and size properties Described herein is a novel method to generate compositions of polypeptide that are derived from B. mori silkworm cocoons and comprise of natural and modified polypeptides. This novel composition is called Low Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at 125 ˚C for 6 hours to achieve the compositions of Low Skid silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Low Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties Low Skid silk/modified polypeptide composition does not self-assemble at 5 mg/mL. Low Skid silk/modified polypeptide composition comprises of a variety of populations of silk/modified polypeptides; here it was sought to isolate distinct populations based on charge, hydrophobicity, and size, by fractionating Low Skid silk/modified polypeptides by anion exchange chromatography, followed by hydrophobic interaction chromatography and size exclusion chromatography. A high-resolution separation of ten distinct Low Skid silk/modified polypeptides compositions was achieved: five are negatively-charged silk compositions that display hydrophobicity characteristics as well – AS90, AS91, AS92, AS93, and AS94. These silk compositions differ from one another by their average size, when AS90 is the largest, and AS94 is the smallest. These silk compositions do not self-assemble under conditions that promote self-assembly at 5 mg/mL. Additional five compositions are negatively charged silk compositions as well, that are less hydrophobic compared to AS90-AS94, and have relatively lower molecular weights (AS95, AS96, AS97, AS98, AS99, AS100). These silk compositions differ from one another by their average size, when AS95 is the largest, and AS100 is the smallest. These silk compositions may have the tendency to aggregate in solution, as can be demonstrated by dynamic light scattering and loss of material after filtration with 0.2 µm PES filter. The Low Skid silk/modified polypeptide compositions described in this invention are novel compositions of silk and modified polypeptides composed of a variety of silk polypeptide populations, generated by the exclusive treatment method of natural silk produced by B. mori. These silk compositions contain modified amino acid sequences that result from the silk processing method and scale. The tight controls over temperature, silk concentration, buffers and salt concentrations, physical agitation, and purification allow us to precisely develop silk compositions with a variety of performance criteria. Isolation of these populations by charge, hydrophobicity, and size reveals new characteristics, like high solubility and stability in solution over time in some populations, and the tendency to aggregate in others. the purification method allows us to isolate silk/modified polypeptide compositions that display biological activities and could be used for therapeutic purposes. Silk is a complex natural biomaterial that has the potential to be utilized in various applications such as the development of implantable medical devices, and the development of soluble polypeptide compositions of medical value. Additionally, it was demonstrated that silk peptides have anti-genotoxic effects However, silk, in its natural form, is not soluble, and silk polypeptide compositions, without the proper processing, display poor solubility in solution and tend to self-assemble and aggregate over time. The kinetics of this self-assembly is unpredictable, and highly depends on the composition of the silk polypeptides/modified composition. Novel silk/modified polypeptide compositions were produced and specific populations were isolated within these compositions. The isolation process allows us to control the properties of the silk compositions and develop products with predictable and desired characteristics. Generation of Low Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100 °C and 60 °C with sodium carbonate and then dried at 60 °C. The silk is then dissolved in 9.3 M Lithium Bromide at 125 °C for 6 hours. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Low Skid/modified polypeptide compositions Isolation of the AS90-AS100 silk/modified polypeptide composition component of Low Skid silk/modified polypeptide composition. To isolate AS90-AS100 Low Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following hydrophobic interactions (HIC) chromatography (Butyl ImpRes colum), followed by HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-HIC-eluate (AS90-94) and of the Q-HIC-flowthrough (AS95-100) (figure 96, 97A, 97B). Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH=8.0. The silk was centrifuged and filtered before loading to the Q- Sepharose column, to remove any preformed aggregates. The silk compositions were loaded onto the Q-Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl2) (Figure 97A). The eluted fractions were pulled together and are referred to as the Q-elution fraction. The Q-flowthrough fraction is colorless and tends to aggregate. The Q-elution was further fractionated by using a Butyl ImpRes column (Figure 97B), which separates polypeptides based on hydrophobicity. The chromatography was performed in the presence of 300 mM ammonium sulfate [(NH₄)₂SO₄], to expose hydrophobic regions within the silk polypeptides. The highly charged flowthrough fraction (Q-HIC-flowthrough) was collected for further fractionation by size exclusion chromatography. The more hydrophobic, bound silk peptides were eluted using 50 mM Tris, pH=8.0 in the absence of ammonium sulfate, to reverse the exposure of the hydrophobic regions in silk polypeptides, which results in their release from the Butyl ImpRes column. The Q-HIC-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Fig.96, Figs.97C and 97D). The fractions that were isolated are AS90-AS94. Then, the Q-HIC-flowthrough fraction was fractionated as well by the HiLoad 26/600 Superdex 200 pg, resulting in the generation of AS95-AS100. Comparing the size exclusion chromatograms of Q-HIC(elution) and Q- HIC(flowthrough) (Fig.97E), it is evident that the Q-HIC(elution) fraction is composed of higher-molecular-weight peptide composition, while the silk peptides that compose the Q- HIC(flowthrough) fraction are eluted later, indicating smaller molecular weights (Also see Figs.99A and 99B for SDS-PAGE of fractions AS90-AS94 (99A) and AS95-AS100 (99B)). Low Skid silk preparation solutions have a characteristic yellow hue. The Q-elution and the Q-HIC-elution fractions had a strong yellow hue, while the Q-flowthrough fraction is transparent, and tends to self-assemble very quickly. The Q-HIC-elution silk compositions that are fractionated by size exclusion (AS90-94) also had a yellow hue. The Q-HIC-flowthrough fractions that were fractionated by size exclusion chromatography (AS95-AS100) were colorless. When silk formulations AS90-AS94 and AS95-AS100 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average Mw, and a different Polydispersity (PDI) value (Figs.98A- 98B, Table 90). Among the Q-HIC-elution fractions, AS90 has the highest Mw (54620 Da), while AS94 has the lowest Mw (21057 Da). The PDI values display a differential change as well. The PDI value of AS90 is the lowest (1.1487), and AS94 is higher (1.3615) (Figs.98A- 98B , Table 90). The Q-HIC-flowthrough fraction is composed of a smaller population of silk peptides, where the first eluted fraction, AS95, has the higher molecular weight among these fractions (45262 Da), 10 kDa smaller than the first eluted fraction of the Q-HIC-elution fraction (AS90). AS100 has the lowest molecular weight among the Q-HIC-flowthrough fractions (22799 Da). In general, AS95-AS100 demonstrate a trend of higher polydispersity compared to AS90-AS94. The PDI value of AS95 is the lowest (1.1988), and AS100 is higher (1.5438) (Figs.98A-98B , Table 90). Unfractionated Low Skid silk has an average Mw of ~19500, indicating that most of the peptide population tends to have lower molecular weight than fractions AS90-AS100. The polydispersity of unfractionated Low Skid silk is ~2.2 – significantly higher than the values of fractions AS90-AS100. This suggests that the unfractionated Low Skid silk is composed of a much diverse peptide population compared to fractions AS90-AS100. AS90-AS94 silk compositions demonstrate relative uniformity by dynamic light scattering and show gradual particle size distribution. In dynamic light scattering analysis (Zetasizer Pro, Figs.101A-101F, Table 89), AS90- AS94 demonstrated relatively uniform, though broad, peaks where AS90 has the largest Z- average (17.617 d. nm), then AS91 (16.803 d. nm), and so on (Table 89), demonstrating the efficiency of the fractionation by size of the Q-HIC-elution fraction (Figs.101C and 101D). Low Skid silk and Mid Skid silk show broad peaks (Figs.101A and 101B), while the AS90 fraction shows more uniformity and narrower peak compared to the two and to the Q-HIC elution fraction, from which AS90 is derived. AS95-AS100 silk compositions display non-uniform silk compositions by dynamic light scattering. AS95-AS100 demonstrate by dynamic light scattering the presence of two major broad peaks for each fraction, indicating a wide range of size of peptide populations (Figs.101E and 101F). The Z-average values of AS95-AS100 are not in descending order like the Z-average of AS90-AS94 and are more variable (Table 89). AS95-A100 fractions and Q-HIC (flowthrough) may have the tendency to aggregate. During the generation AS95-AS100 there has been an extensive loss of protein material. By following the UV280 detection of protein amount that was flowed through the Butyl ImpRes column and did not bind the column, it was expected to find a large amount of silk peptides in solution. However, during size-exclusion chromatography, the amount of silk peptides in the resulting fractions was low (Fig.99B). It is hypothesized that a large portion of the silk peptides has aggregated or did not go through the filtration step of the Q- HIC(flowthrough), and was lost before loading onto the gel filtration column. SDS-PAGE of AS95-AS100 that was run immediately after size exclusion chromatography (Fig.99B ) showed distinct populations of silk peptides, in a descending order of molecular weight. However, dynamic light scattering analysis that was performed later showed diverse size populations. This can indicate an aggregation over time of silk peptides in fractions AS95- AS100. Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self assembly assay and data derived from it. To study the stability of silk/modified peptide compositions in solution Self-Assembly assays were performed at a concentration of 5 mg/mL. The absorbance at 550 nm curves of the self-assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is:

A_max is the maximum densify of the gel formed

Zr is the Self-Assembly Rate Factor (SARF) to.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve

(see Fig. 100 the red dotted lines for a better demonstration of how these factors from the Self- Assembly experiments are calculated)

Another parameter that was introduced to characterize the propensity of silk to form gels is the Self-Assembly Factor (FSAF) which is:

Using the experimental data from the Self-Assembly assays performed with the various novel isolated silk polypeptides, these parameters were calculated and used to dissect their properties (Fig. 100). Four parameters were focused on, collectively referred to as Self- Assembly kinetic factors; the Self-Assembly Rate Factor (SARF), A_max, t0.5, and the Self- Assembly Factor (SAF) (Fig. 100). The SARF shows how fast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed; A_max shows how dense is the gel that is formed after self-assembly is complete, t0.5 shows how long it takes for the self- assembly reaction to reach the point where gel densify is and SAF shows the propensity

of silk to self-assemble (Fig. 100).

AS90-AS94 silk compositions do not self-assemble.

Self-assembly assays revealed that Low Skid silk/modified peptide compositions do not self-assemble under the experimental system conditions (Fig. 100). Mid Skid/modified peptide compositions was used as a positive control and shows fast self-assembly kinetics (Fig. 100). Fractions AS95-AS100 were not tested for self-assembly since the purification process did not result in sufficient amount of silk peptides to perform the assay.

Materials and Methods used for the generation and characterization of AS90-AS100. Anion exchange chromatography of silk. Low Skid silk was provided by the manufacturing team at a concentration of 60 mg/mL. 50 mM Tris, pH=8.0 buffer was added to the Low Skid silk, and the silk was centrifuged at 16000 rpm (rotor JA-18, Beckman coulter, average of 28100 xg), at 4˚ C, for 30 min to separate formed aggregates from soluble silk. The supernatant was collected and filtered through a 0.22 µm PES filter. For silk fractionation Q-Sepharose prepacked columns connected to an AKTA pure 25 L or HiPrep Q FF 16/1020 mL Column, or HiTrap™ Capto™ Q 1 mL column were used. All buffers used were filtered through a 0.22 μm PES filter and degassed with sonication. Centrifuged and filtered Low Skid silk was loaded on 5 x 5 mL HiTrap Q HP columns washed with 10 column volumes of 50 mM Tris pH=8.0, 10 column volumes of 50 mM Tris pH=8.0, 500 mM CaCl₂ and finally 10 column volumes of 50 mM Tris pH=8.0.150 mL of centrifuged Low Skid silk were loaded on the column with a flow rate of 5 mL/min. The flow-through was collected. The column was washed with 50 mM Tris pH=8.0 until the absorbance at 280 nm [A280] got to 100 AU. Bound protein was eluted in one step with 50 mM Tris pH=8.0, 500 mM CaCl₂ and all fractions with absorbance [A₂₈₀] >500AU were pooled together. This process was performed twice (total 300 ml of starting material of Low Skid silk was fractionated).The Q-elution fractions (the eluate) were then used for further fractionation by hydrophobic interactions chromatography. Hydrophobic Interactions Chromatography of Silk. The buffer of Q-eluate was exchanged with water with dialysis in x 100 volumes of water. After the buffer exchange was complete, 50mM Tris pH=8.0, 300mM (NH₄)₂SO₄ were added to the Q-eluate. A column of Butyl ImpRes resin was used for the creation of AS90- AS100. The Butyl ImpRes column was washed with x10 column volumes of degassed and filtered (0.22 μm) 50 mM Tris pH=8.0, 300 mM (NH₄)₂SO₄, 10 x column volumes of degassed and filtered (0.22 μm) 50 mM Tris pH=8.0 and 10 x column volumes of degassed and filtered (0.22 μm) 50 mM Tris pH=8.0, 300 mM (NH₄)₂SO₄. The Q-eluate (200 mL) was used for the fractionation. Q-eluate silk was in 50 mM Tris pH=8.0, 300 mM (NH₄)₂SO₄ and loaded on the Butyl ImpRes column. All unbound proteins (the flowthrough fraction) were collected and saved for further analysis. After loading was complete, the Butyl ImpRes column was washed 10 x column volumes of 50 mM Tris pH=8.0, 300 mM (NH₄)₂SO₄ until the OD280=about 100 AU. After the washing step was complete, bound silk molecules were eluted with 1.5 x column volumes of 50mM Tris pH=8.0. The elution was collected, and both Q-HIC(elution) and Q- HIC(flowthrough) fractions were transferred to dialysis bags and dialyzed against 3 mM Tris, pH=8.0. The two fractions were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da and saved for further fractionation by size exclusion chromatography. Size Exclusion Chromatography of Silk. Both the elution fraction of the hydrophobic interactions chromatography (Q-HIC- elution) and the flowthrough fraction (Q-HIC-flowthrough) were filtered (0.22 µm PES filter) to discard preformed aggregates, and fractionated separately by size exclusion chromatography. The eluate or the flowthrough fraction was loaded onto a HiLoad 26/600 Superdex 200 pg gel filtration column for fractionation, using the AKTA Pure 25L system. All buffers used during fractionation were filtered through 0.22 µm PES filter and were degassed. The Q-HIC(elution) or Q-HIC(flowthrough) fractions were loaded on the Superdex 200 gel filtration column, and were run with 50 mM Tris, 200 mM CaCl2, pH=8.0. The eluted silk compositions were collected in 10 ml fractions. Fractions 6-10 of the Q-HIC(elution) (AS90, AS91, AS92, AS93, AS94) were collected, and have relatively narrow range of molecular weight. Fractions 8-13 (AS95, AS96, AS97, AS98, AS99, AS100) were collected during the fractionation of Q-HIC(flowthrough). The fractions were placed in 3.5 kDa cutoff dialysis bags, and were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da. Then, fractions in the dialysis bags were immersed in 160X volumes of 50 mM Tris pH=8.0 overnight, and then were immersed in a new batch of 160X volume of 50 mM Tris pH=8.0. Samples were kept at 4˚C until they were used. Analytical/Protein Characterization methods. Protein concentration determination. Protein concentration was determined by absorbance at 220 nm or 280 nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1AU=1 mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analytical Size Exclusion Chromatography is performed as described in detail in the document EMED-QCP-SILK1-002. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm connected to an Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1 M NaCl, 12.5 mM Na2HPO4, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2 μm PES filter into a clean glass media bottle).25 μL of sample were loaded on the column and the analysis was performed at 25 ^oC with a flow rate of 1 mL/min for 20 min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. SDS polyacrylamide gel. Low Skid silk fractions were loaded onto a Mini-Protean TGX precast gel, 4-20%, with a protein marker Trident Prestained Protein Ladder for molecular weight reference. The SDS polyacrylamide gel was stained using ReadyBlue™ Protein stain gel. Gels were immersed in ReadyBlue™ solution for 1 h, then destained with DI/RO water. Self-Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50mM CH₃COONa pH=5. Each reaction was done in a final volume of 200 μL. Total silk protein concentration was 5 mg/mL. First, the buffer of 50 mM CH₃COONa pH=5.0, 35% v/v 2- propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully, so as to not create any bubbles. Absorbance was recorded at 550 nm for 24 h. Dynamic Light Scattering analysis of silk compositions. Low and Mid Skid silk compositions were diluted to a concentration of 1 mg/mL and filtered with a 0.22 µm PES syringe filter. All measurements were performed with a Malvern Zetasizer Pro Red Label, detection angle of 173˚. The Red Label system operates with a 10 mW He-Ne laser (633 nm). The software used is ZS XPLORER version 3.2.1.11. All measurements were done with 4.2 ml polystyrol/polystyrene transparent cuvettes. Samples were measured at 25˚ C, with 120 sec of equilibration time. The intensity size distributions, autocorrelation, and Z- average were measured. Tables

Table 89: Z-average of AS90-AS100 calculated by Dynamic Light Scattering. The Z- average value of each silk/modified polypeptide composition was calculated by the Zetasizer Pro. Shown here are the Z-average values of each silk composition. The abbreviation d. nm refers to the diameter in nanometers.

Table 90: Molecular weight (Mw) and Polydispersity (PDI) values of silk compositions AS90-AS100. Silk/modified polypeptide compositions AS90-AS100 were analyzed by size exclusion chromatography (SEC) column with HPLC, and values of molecular weights (Mw) and Polydispersity (PDI) are indicated. Example 40: Mid Skid Silk/Modified Polypeptide Compositions Isolated by Size Properties. Described herein is a novel method to generate compositions of polypeptide that are derived from B. mori silkworm cocoons and comprise of natural and modified polypeptides. This novel composition is called Mid Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at 103˚C for 1 hour to achieve the compositions of Mid Skid silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Mid Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties. Mid Skid silk/modified polypeptide composition self-assembles at 5 mg/mL. Mid Skid silk/modified polypeptide composition comprises of a variety of populations of silk/modified polypeptides; here it was sought to isolate distinct populations based on size, by fractionating Mid Skid silk/modified polypeptides by size exclusion chromatography. A high-resolution separation of six silk compositions was achieved – AS106, AS107, AS108, AS109, AS110, and AS111. These silk compositions differ from one another by their average size, when AS106 is the largest, and AS111 is the smallest. These silk compositions self- assemble under conditions that promote self-assembly at 5 mg/mL. The Mid Skid silk/modified polypeptide compositions described in this invention are novel compositions of silk and modified polypeptides composed of a variety of silk polypeptide populations, generated by the exclusive treatment method of natural silk produced by B. mori. These silk compositions contain modified amino acid sequences that result from the silk processing method and scale. The tight controls over temperature, silk concentration, buffers and salt concentrations, physical agitation, and purification allow for the precise development of silk compositions with a variety of performance criteria. Isolation of these populations by charge and size reveals new characteristics, like high solubility and stability in solution over time in these populations. the purification method allows us to isolate silk/modified polypeptide compositions that display biological activities and could be used for therapeutic purposes. Silk is a complex natural biomaterial that has the potential to be utilized in various applications such as the development of implantable medical devices, and the development of soluble polypeptide compositions of medical value. Additionally, it was demonstrated that silk peptides have anti-genotoxic effects. However, silk, in its natural form, is not soluble, and silk polypeptide compositions, without the proper processing, display poor solubility in solution and tend to self-assemble and aggregate over time. The kinetics of this self-assembly is unpredictable, and highly depends on the composition of the silk polypeptides/modified composition. ovel silk/modified polypeptide compositions were produced and specific populations were isolated within these compositions. The isolation process allows for control of the properties of the silk compositions and development of products with predictable and desired characteristics. Generation of Mid Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100 ˚C and 60 ˚C with sodium carbonate and then dried at 60 ˚C. The silk is then dissolved in 9.3 M Lithium Bromide at 103 ˚C for 1 hour. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Mid Skid/modified polypeptide compositions Isolation of the AS106-AS111 silk/modified polypeptide composition component of Mid Skid silk/modified polypeptide composition. To isolate AS106-AS111, Mid Skid silk/modified polypeptide compositions were fractioned using HiLoad 26/600 Superdex 200 pg size exclusion chromatography column (Figs.102, 103). Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH=8.0. The silk was centrifuged and filtered before loading to the HiLoad 26/600 Superdex 200 pg column, to remove any preformed aggregates. The silk compositions were fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Figs.104A-104B &405). Mid Skid silk preparation solutions have a characteristic yellow hue, and the fractionated silk compositions had a light-yellow hue. When silk formulations AS106-AS111 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average molecular weight, and a different Polydispersity (PDI) value (Figs.104A-104B, Table 92). In general, AS106 has the highest molecular weight (89297 Da), while AS111 has the lowest molecular weight (35474 Da). Unfractionated Mid Skid silk had the lowest Mw (29265 Da), indicating that the majority of peptide population in Mid Skid silk are of lower molecular weight. The PDI values display a differential change as well. The PDI value of AS106 is relatively low (1.2866), and AS111 is higher (1.4702) (Figs. 104A-104B, Table 92). Unfractionated Mid Skid silk has the highest PDI – 1.6985, indicating a broad and diverse peptide population sizes. AS106-AS111 compositions contain multiple peptide populations sizes. In dynamic light scattering analysis (Zetasizer Pro, Figs.107A-107B, Table 91), AS106-AS111 demonstrated multiple peptide size population by having two broad peaks for each fraction, similar to unfractionated Mid Skid silk (Fig.107A). There is a shift in the molecular size of each fraction, where AS106 had the largest Z-average value (53.71 d. nm), and AS111 silk composition had the lowest (25.34 d. nm). Despite fractionation by size exclusion chromatography, each fraction contains a range of peptides in different molecular sizes, as can be observed by SDS gel electrophoresis in Fig.105. Dynamic light scattering shows two peaks for these fractions, indicating the presence of several populations (Fig.107A). Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self-Assembly assay and data derived from it. To study the stability of silk/modified peptide compositions in solution, Self-Assembly assays were performed at a concentration of 5 mg/mL. The absorbance at 550 nm curves of the self-assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is:

A_max is the maximum density of the gel formed k is the Self-Assembly Rate Factor (SARF) t_0.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve (see Fig.106 the red dotted lines for a better demonstration of how these factors from the Self- Assembly experiments were calculated) Another parameter introduced to characterize the propensity of silk to form gels is the Self- Assembly Factor (FSAF) which is:

Using the experimental data from the Self-Assembly assays that were performed with the various novel isolated silk polypeptides, these parameters were calculated and used to dissect their properties (Fig. 106). Four parameters were focused on, collectively referred to as Self-Assembly kinetic factors; the Self-Assembly Rate Factor (SARF), A_max, t0.5, and the Self- Assembly Factor (SAF) (Fig. 106 ). The SARF shows how fast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed; Amt shows how dense is the gel that is formed after self-assembly is complete, t0.5 shows how long it takes for the self- assembly reaction to reach the point where gel density is and SAF shows the propensity

of silk to self-assemble (Fig. 106). For all parameter calculations, please see Table M.

AS106-AS111 silk compositions demonstrate high self-assembly characteristics.

Self-assembly assays revealed that Mid Skid silk/modified peptide compositions AS106-AS111 self-assemble highly efficiently under the experimental system conditions (Fig. 106). All Mid Skid fractions tested form denser gel in shorter time compared to unfractionated Mid Skid silk. This finding may indicate that components that promote self-assembly are of higher molecular w eight, since the unfractionated Mid Skid silk contains a large populations of lower molecular weight peptides, but silk compositions AS106-AS111 are fractionated by size and contain higher molecular weight peptide populations (Fig. 104A-104B & 105). Low Skid silk was used as a negative control, no self-assembly occurred after 17 hours.

Materials and Methods used for the generation and characterization of AS106-AS111. Size Exclusion Chromatography of Silk.

The starting material, Mid Skid silk at a concentration of 60 mg/mL, was provided by the manufacturing team. The Mid Skid silk was transferred to 50 mM Tris, pH=8.0 buffer, and centrifuged at 16000 rpm (rotor JA-18, Beckman coulter, average of 28100 xg), at 4 °C, for 30 min to separate formed aggregates from soluble silk. The supernatant was collected and filtered through a 0.22 pm PES filter. Then, the silk was loaded onto a HiLoad 26/600 Superdex 200 pg gel filtration column for fractionation, using the AK.TA Pure 25L system. All buffers used during fractionation were filtered through 0.22 μm PES filter as well and were degassed. The Mid Skid silk w as loaded on the Superdex 200 gel filtration column, and was run with 50 mM Tris, 200 mM CaCl₂ . pH8, to fractionate the Mid Skid silk. The eluted silk compositions were collected in 10 ml fractions. Fractions 5-10 (AS106, AS107, AS108. AS109, AS110, AS111) were collected. The fractions were placed in 3.5 kDa cutoff dialysis bags, and were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da. Then, fractions in the dialysis bags were immersed in 160X volumes of 50 mM Tris pH=8.0 overnight, and then were immersed in a new batch of 160X volume of 50 mM Tris pH=8.0. Samples were kept at 4 ˚C until they were used. Analytical/Protein Characterization methods. Protein concentration determination. Protein concentration was determined by absorbance at 220nm or 280nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1AU=1mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm connected to an Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1M NaCl, 12.5 mM Na₂HPO₄, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2 μm PES filter into a clean glass media bottle).25 μL of sample were loaded on the column and the analysis was performed at 25 °C with a flow rate of 1 mL/min for 20 min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. SDS polyacrylamide gel. Mid Skid silk fractions were uploaded onto a Mini-Protean TGX precast gel, 4-20%, with a protein marker Trident Prestained Protein Ladder for molecular weight reference. The SDS polyacrylamide gel was stained using ReadyBlue™ Protein stain gel. Gels were immersed in ReadyBlue™ solution for 1 h, then destained with DI/RO water. Self-Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50 mM CH₃COONa pH=5. Each reaction was done in a final volume of 200. μL. Total silk protein concentration was 5 mg/mL. First the buffer of 50 mM CH₃COONa pH=5, 35% v/v 2-propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully so as to not create any bubbles. Absorbance was recorded at 550 nm for 17 h. Recorded values were exported in Excel files for storage and further analysis. Dynamic Light Scattering analysis of silk compositions. Mid Skid silk compositions were diluted to a concentration of 1 mg/mL and filtered with a 0.22 µm PES syringe filter. All measurements were performed with a Malvern Zetasizer Pro Red Label, detection angle of 173˚. The Red Label system operates with a 10 mW He-Ne laser (633 nm). The software used is ZS XPLORER version 3.2.1.11. All measurements were done with 4.2 mL polystyrol/polystyrene transparent cuvettes. samples were measured at 25 ˚C, with 120 sec of equilibration time. The intensity size distributions, autocorrelation, and Z- average were measured. Tables

Table 91: Z-average of AS106-AS111 calculated by Dynamic Light Scattering. The Z- average value of each silk/modified polypeptide composition was calculated by the Zetasizer Pro. Shown here are the Z-average values of each silk composition. MS, Mid Skid silk.

Table 92: Molecular weight (Mw) and Polydispersity (PDI) values of silk compositions AS106-AS111. Silk/modified polypeptide compositions AS106, AS107, AS108, AS109, AS110, and AS111 were analyzed by size exclusion chromatography (SEC) column with HPLC, and values of molecular weights (Mw) and Polydispersity (PDI) are indicated. A A A A A A M

Table 93: Calculated self-assembly parameters of silk compositions AS106-AS111. For detailed description of how these parameters are calculated, please see Description of Invention section, Self-Assembly. MS, Mid Skid silk. Example 41: Mid Skid Silk/Modified Polypeptide Compositions Isolated by Charge and Size Properties. Described herein is a novel method to generate compositions of polypeptide that are derived from B. mori silkworm cocoons and comprise of natural and modified polypeptides. This novel composition is called Mid Skid silk/modified polypeptide compositions. The novel production method involves removing sericin through several washing steps with an organic sodium carbonate salt with tightly controlled multi-stage temperature cycles and agitation as the first step in forming natural/modified polypeptide composition. Next the silk is dried to remove remaining water at controlled temperature to maintain polypeptide composition. The silk is then dissolved in high concentration of Lithium salt at 103 ˚C for 1 hour to achieve the compositions of Mid Skid silk. The liquid solution is then filtered and purified to remove the Lithium salt leaving only the natural/modified silk compositions in solution with pure water. Mid Skid silk/modified polypeptide compositions comprise of populations of silk/modified polypeptides with distinctive properties. Mid Skid silk/modified polypeptide composition self-assembles at 5 mg/mL. Mid Skid silk/modified polypeptide composition comprises of a variety of populations of silk/modified polypeptides; here it was sought to isolate distinct populations based on charge and size, by fractionating Mid Skid silk/modified polypeptides by anion exchange chromatography and size exclusion chromatography. A high-resolution separation of five negatively-charged silk compositions was achieved – AS101, AS102, AS103, AS104, and AS105. These silk compositions differ from one another by their average size, when AS101 is the largest, and AS105 is the smallest. These silk compositions self-assemble under conditions that promote self-assembly at 5 mg/mL. The Mid Skid silk/modified polypeptide compositions described in this invention are novel compositions of silk and modified polypeptides composed of a variety of silk polypeptide populations, generated by the exclusive treatment method of natural silk produced by B. mori. These silk compositions contain modified amino acid sequences that result from the silk processing method and scale. The tight controls over temperature, silk concentration, buffers and salt concentrations, physical agitation, and purification allow us to precisely develop silk compositions with a variety of performance criteria. Isolation of these populations by charge and size reveals new characteristics, like high solubility and stability in solution over time in these populations. the purification method allows us to isolate silk/modified polypeptide compositions that display biological activities and could be used for therapeutic purposes. Silk is a complex natural biomaterial that has the potential to be utilized in various applications such as the development of implantable medical devices, and the development of soluble polypeptide compositions of medical value. Additionally, it was demonstrated that silk peptides have anti-genotoxic effects. However, silk, in its natural form, is not soluble, and silk polypeptide compositions, without the proper processing, display poor solubility in solution and tend to self-assemble and aggregate over time. The kinetics of this self-assembly is unpredictable, and highly depends on the composition of the silk polypeptides/modified composition. Novel silk/modified polypeptide compositions were produced and specific populations were isolated within these compositions. The isolation process allows for control of the properties of the silk compositions and development of products with predictable and desired characteristics. Generation of Mid Skid silk/modified polypeptide compositions. Silk is washed to remove sericin at 100˚C and 60˚C with sodium carbonate and then dried at 60˚C. The silk is then dissolved in 9.3 M Lithium Bromide at 103˚C for 1 hour. This dissolution step controls not only molecular weight but also the polypeptide modifications creating the natural/modified silk compositions. The silk is then filtered to remove undissolved debris and purified using 10 kDa cutoff PES hollow fiber membranes and concentrated using the same process leaving only natural/modified silk composite in solution with pure water. Every unit ops is tightly controlled for temperature, time, concentrations, agitation, and shear. Isolation of Mid Skid/modified polypeptide compositions Isolation of the AS101-AS105 silk/modified polypeptide composition component of Mid Skid silk/modified polypeptide composition. To isolate AS101-AS105, Mid Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-eluate (Figs.108, 109A, and 109B). Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH=8.0. The silk was centrifuged and filtered before loading to the Q-Sepharose column, to remove any preformed aggregates. The silk compositions were loaded onto the Q-Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl2). The eluted fractions were pulled together and are referred to as the Q-elution fraction. The Q-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Figs. 110A-110B & 111). Mid Skid silk preparation solutions have a characteristic yellow hue. The Q-elution fraction has a strong yellow hue, while the flowthrough fraction is transparent, and tends to self-assemble very quickly. The Q-elution silk compositions that are fractionated by size exclusion also had a yellow hue. When silk formulations AS101-AS105 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average Mw, and a different Polydispersity (PDI) value (Figs.110A-110B, Table 95). In general, AS101 has the highest Mw (60949 Da), while AS105 has the lowest Mw (32804 Da). The PDI values display a differential change as well. The PDI value of AS101 is relatively low (1.1347), and AS105 is higher (1.3937) (Figs. 110A-110B, Table O). Unfractionated Mid Skid silk has an average Mw of 29265, indicating that most of the peptide population tends to have lower molecular weight than fractions AS101-AS105. The polydispersity of unfractionated Mid Skid silk is 1.6985 – significantly higher than the values of fractions AS101-AS105. This indicated that the unfractionated Mid Skid silk is composed of a much diverse peptide population compared to fractions AS101- AS105, where the majority of the peptide populations have lower molecular weight. AS101-AS105 silk compositions demonstrate that majority of the peptide populations are relatively uniform by dynamic light scattering and show gradual particle size distribution. In dynamic light scattering analysis (Zetasizer Pro, Figs.113A-113C, Table 94), AS101-AS105 showed two peaks for each fraction, where the intensity is higher for the smaller size distribution compared to the larger size distribution peak. Comparing to unfractionated Mid Skid (Fig.113B), which has two populations that are very close in intensity, it is evident that the Q-SEC fractionation enriched the populations that are of smaller hydrodynamic radius, and the separation between different fractions is efficient, as can be seen by the gradual decrease in size from fraction to fraction (Figs.113A-113B , Table 94). AS101 has the largest Z-average (21.905 d. nm), then AS102 (18.735 d. nm), and so on (Table 94), demonstrating the efficiency of the fractionation by size of the Q-elution fraction. Self-Assembly of Low and Mid Skid/modified polypeptide compositions Self-assembly assay and data derived from it. To study the stability of silk/modified peptide compositions in solution, Self- Assembly assays were performed at a concentration of 5 mg/mL. The absorbance at 550 nm curves of the self-assembly assays are sigmoid and they can be described as logistic curves. The typical logistic function is:

Amax is the maximum density of the gel formed k is the Self-Assembly Rate Factor (SARF) t0.5 is the time point at which 50% of the gel has formed e is the exponential equation for the specific curve (see Fig.111 the red dotted lines for a better demonstration of how these factors from the Self-Assembly experiments were calculated) Another parameter introduced to characterize the propensity of silk to form gels is the Self- Assembly Factor (FSAF) which is:

Using the experimental data from the Self-Assembly assays that were performed with the various novel isolated silk polypeptides, these parameters were calculated and used to dissect their properties (Fig.111). Four parameters were focused on, collectively refered to as Self-Assembly kinetic factors; the Self-Assembly Rate Factor (SARF), Amax, t0.5, and the Self-Assembly Factor (SAF) (Fig.111). The SARF shows how fast silk self-assembles to form gel after the reaction begins or the gelation nuclei have formed; Amax shows how dense is the gel that is formed after self-assembly is complete, t0.5 shows how long it takes for the self-assembly reaction to reach the point where gel density is A_max/2 and SAF shows the propensity of silk to self-assemble (Fig.111). AS101-AS105 self-assemble in different kinetics to form a gel, while the Q-elution fraction self-assembles poorly. Silk compositions AS101-AS105 were tested for their ability to self-assemble and form a gel. The starting material for generating silk compositions AS101-AS105 was the Q- elution fraction (Fig.108), which did not demonstrate significant self-assembly (Fig.111). However, silk compositions AS101-AS105, derived from the Q-elution fraction, self- assembled to form a gel in different kinetics (Fig.111, Table 96). This indicates that separating the higher-molecular-weight peptide populations from the lower-molecular-weight peptide population in Q-elution fraction allows them to self-assemble to form a gel. AS101 reached the lowest Amax, meaning the formed gel was the least dense. AS105 silk composition had the highest t0.5 value: the formation of the gel took the longest, and the gelation nuclei took longer to form. The collected Q-flowthrough fraction self-assembles exceptionally fast and forms the densest gel of all fractions. While fractionating silk by anion exchange, the flowthrough fraction (Q-FT) was collected (Fig.109A) and demonstrated spontaneous slow self-assembly in 4 ˚C. To compare the self-assembly capabilities of Q-FT to Mid Skid silk and the further fractionated silk compositions, the Q-FT in the self-assembly assay was tested. The Q-FT fraction showed extraordinary capability of self-assembly under the assay’s conditions and started to self- assemble in less than 1 h (Fig.111, Table 96). The density of the formed gel was the highest of all silk compositions tested. These results show that the uncharged/positively charged silk compositions/modified peptides that were separated from the negatively charged population by anion exchange have a much higher tendency to self-assemble. Materials and Methods used for the generation and characterization of AS101-AS105. Anion exchange chromatography of silk. Mid Skid silk was provided by the manufacturing team at a concentration of 60 mg/mL.50 mM Tris, pH=8.0 buffer was added to the Mid Skid silk, and the silk was centrifuged at 16000 rpm (rotor JA-18, Beckman coulter, average of 28100 xg), at 4 ˚C, for 30 min to separate formed aggregates from soluble silk. The supernatant was collected and filtered through a 0.22 µm PES filter. For silk fractionation Q-Sepharose prepacked columns connected to an AKTA pure 25 L or HiPrep Q FF 16/1020 mL Column were used. All buffers used were filtered through a 0.22 μm PES filter and degassed with sonication. Centrifuged and filtered Mid Skid silk was loaded on HiPrep Q FF 16/1020 mL column, washed with 10 column volumes of 50 mM Tris pH=8.0, 10 column volumes of 50 mM Tris pH=8.0, 500 mM CaCl2 and finally 10 column volumes of 50 mM Tris pH=8.0.150 mL of centrifuged Mid Skid silk were loaded on the column with a flow rate of 5 mL/min. The flow-through was collected. The column was washed with 50 mM Tris pH=8.0 until the absorbance at 280 nm [A280] got to 100 AU. Bound protein was eluted in one step with 50 mM Tris pH=8.0, 500 mM CaCl2 and all fractions with absorbance [A280] >500AU were pooled together. The Q-elution fraction (the eluate) was then used for further fractionation by size exclusion chromatography. Size Exclusion Chromatography of Silk. The Mid Skid silk eluate fraction of the Q-Sepharose anion exchange chromatography (Q-elution) was the starting material for size exclusion chromatography. The eluate was loaded onto a HiLoad 26/600 Superdex 200 pg gel filtration column for fractionation, using the AKTA Pure 25 L system. All buffers used during fractionation were filtered through 0.22 µm PES filter as well and were degassed. The Mid Skid silk was loaded on the Superdex 200 gel filtration column, and was run with 50 mM Tris, 200 mM CaCl2, pH=8.0, to fractionate the Q-elution Mid Skid silk. The eluted silk compositions were collected in 10 ml fractions. Fractions 6-10 (AS101, AS102, AS103, AS104, AS105) were collected, and have relatively narrow range of molecular weight. The fractions were placed in 3.5 kDa cutoff dialysis bags, and were concentrated by covering the dialysis bags with polyethylene glycol 35000 Da. Then, fractions in the dialysis bags were immersed in 160X volumes of 50 mM Tris pH=8.0 overnight, and then were immersed in a new batch of 160X volume of 50 mM Tris pH=8.0. Samples were kept at 4 ˚C until they were used. Analytical/Protein Characterization methods. Protein Concentration Determination. Protein concentration was determined by absorbance at 220 nm or 280 nm. Solubilized silk preparations were diluted until A280 was between 0.1-1. In this range the absorbance correlates linearly with the concentration of silk in the solution and the correlation is 1AU=1mg/mL soluble silk proteins. Final concentrations in the initial silk solution were calculated after adjustment for the dilution used for the absorbance measurement. Analytical Size Exclusion Chromatography. Analytical Size Exclusion Chromatography is performed as described in detail in the document EMED-QCP-SILK1-002. Analysis was performed in a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm connected to an Agilent 1260 Infinity II HPLC system with an Agilent G7162A RID Refractive Index Detector. The mobile phase used for the analysis was a solution of 0.1 M NaCl, 12.5 mM Na₂HPO₄, pH 7 (the pH was adjusted with phosphoric acid and filtered through a 0.2μm PES filter into a clean glass media bottle).25μL of sample were loaded on the column and the analysis was performed at 25 °C with a flow rate of 1 mL/min for 20 min. Calculation of the molecular weight of each sample was done using Agilent Technologies Open LAB CDS ChemStation Edition for LC & LC/MS Systems software Cirrus SEC data collection and molecular weight analysis software. SDS polyacrylamide gel. Mid Skid silk fractions were loaded onto a Mini-Protean TGX precast gel, 4-20%, with a protein marker Trident Prestained Protein Ladder for molecular weight reference. The SDS polyacrylamide gel was stained using ReadyBlue™ Protein stain gel. Gels were immersed in ReadyBlue™ solution for 1 h, then destained with DI/RO water. Self-Assembly Assay. The silk Self Assembly Assay (SAF) was performed in 35% v/v 2-propanol and 50mM CH₃COONa pH=5. Each reaction was done in a final volume of 200 μL. Total silk protein concentration was 5 mg/mL. First the buffer of 50 mM CH₃COONa pH=5.0, 35% v/v 2-propanol was prepared. Then DI/RO water was added so that after the addition of the volume of silk protein required to reach a final concentration of 5 mg/mL the total volume would be 200 μL. The protein was added last and mixed with very gentle pipetting to reduce shearing force. The protein mixtures were placed in wells of flat-bottom 96-well plates and a layer of 100 μL of Mineral Oil carefully, so as to not create any bubbles. Absorbance was recorded at 550 nm for 24 h. Recorded values were exported in Excel files for storage and further analysis. Dynamic Light Scattering analysis of silk compositions. Mid Skid silk compositions were diluted to a concentration of 1 mg/mL and filtered with a 0.22 µm PES syringe filter. All measurements were performed with a Malvern Zetasizer Pro Red Label, detection angle of 173˚. The Red Label system operates with a 10 mW He-Ne laser (633 nm). The software used is ZS XPLORER version 3.2.1.11. All measurements were done with 4.2 ml polystyrol/polystyrene transparent cuvettes. samples were measured at 25 ˚C, with 120 sec of equilibration time. The intensity size distributions, autocorrelation, and Z-average were measured. Tables

Table 94: Z-average of AS101-AS105 calculated by Dynamic Light Scattering. The Z- average value of each silk/modified polypeptide composition was calculated by the Zetasizer Pro. Shown here are the Z-average values of each silk composition. The abbreviation d. nm refers to the diameter in nanometers.

Table 95: Molecular weight (Mw) and Polydispersity (PDI) values of silk compositions AS101-AS105. Silk/modified polypeptide compositions AS101, AS102, AS103, AS104, AS105, and unfractionated Mid Skid silk were analyzed by size exclusion chromatography (SEC) column with HPLC, and values of molecular weights (Mw) and Polydispersity (PDI) are indicated. A A A A A Q M

Table 96: Calculated self-assembly parameters of silk compositions/modified peptides. For detailed description of how these factors are calculated, please see Description of Invention section, Self-Assembly. Q-FT, flowthrough fraction collected during anion exchange chromatography using a Q column. Example 42: Absolute Weight Average Molecular Weight and Polydispersity of Low, Mid, and High Molecular Weight Silk by SEC-MALS Development of Low, Mid, and High Molecular Weight Silk Summary of Methodologies to Measure Molecular Weight This example discusses the measurement of molar mass moments, specifically Mw, by SEC-MALS. Molar mass can be used interchangeably with the term “molecular weight”. For the sake of clarity, molar mass will be used in this example. Measuring Molar Mass Moments by SEC-RI The methodology previously used for molar mass determination was SEC-RI. The following section is intended to describe the differences of the two methods and how both can exist in future fillings. As both methods produce a reported value of weight-averaged molecular weight (Mw), it is recommended that the Mw values be redefined as “absolute Mw” for SEC-MALS and “relative Mw” for SEC-RI. Summary SEC is a mode of chromatographic separation and, on its own, cannot provide an absolute molar mass. Instead, SEC can provide a relative molar mass of a protein (or polymer) against a calibration curve of standard; this conventional calibration method provides a relative molar mass. SEC is often paired with a RI detector which is concentration-sensitive and molar- mass-insensitive. Additional Information: With SEC, molecules are separated by hydrodynamic size (larger molecules having a shorter retention time than smaller molecules) which is correlated to molar mass. Herein, the retention time of the protein of interest is related to the calibration curve comprised of proteins or polymers of known molar mass. The caveat is that the unique structure or shape of a protein will impact the retention time in SEC; this may lead to erroneous reported molecular weights especially if the protein of interest differs significantly from the calibration curve. However, this method is commonly used as an industry-standard as LS detectors and such SEC-MALS has not been universally adopted as the singular molecular weight determination method. Measuring Molar Mass Moments by SEC-MALS This example reports molecular weight and polydispersity as measured by Size Exclusion Chromatography-Multi-Angle Light Scattering (SEC-MALS) for fractionated silk. SEC-MALS produces an absolute weight averaged molar mass (Mw) measurement as compared to the relative molar mass measurement produced by a conventional calibration method such as SEC-RI. Two detectors were used in the calculation of molar mass moments by SEC-MALS in this document: a refractive index (RI) detector and light scattering (LS) detector. RI detector provides the concentration of the protein. LS detector provides the weight-average molar mass (Mw) of the protein directly and absolutely; the intensity of scattered light is directly proportionate to the Mw of the molecule. LS is the most widely used technique for determining Mw. Calculation of Molar Mass Moments The calculation of molar mass moments uses the following variables: ni, Mi, and ci. Mi, and ci are directly measured by SEC-MALS. Note that the subscript “i” indicates that the value is calculated at each slice of peak of interest. • ni is the number of molecules • Mi is the molecular mass of the molecules (measured by LS detector) • c_i is the concentration of material as measured by the concentration detector (measured by RI detector) Number-average molar mass, Mn, is related to an arithmetic mean where the total mass is divided by the number of molecules.

For the weight-average molecular mass, Mw:

Calculation of Polydispersity Index (PDI) The ratio of Mw and Mn produces the PDI value as calculated by ASTRA software. A polydisperse macromolecule has a PDI > 1.05 and a monodisperse macromolecular has a PDI < 1.05 (Error! Reference source not found.). Results For Low Molecular Weight silk (Low MW Silk), the method of manufacturing has little impact on Mw but can lead to marked difference in PDI. The weight-average molecular weight range for Low MW Silk was 35.9 to 41.2 kDa (Table ). The average Mw was 38.4 kDa (5% RSD) for Low MW Silk. More significant differences were measured by PDI where Low MW silk produced with the Benchtop Method had the highest PDI (2.051) while the PDI was roughly 1.5 for other lots of Low MW Silk. The polydispersity range for Low MW Silk was 1.416 to 2.051. For Mid Molecular Weight silk (Mid MW Silk), the method of manufacturing has little impact on Mw but can lead to marked difference in PDI. The weight-average molecular weight range for Mid MW Silk was 51.8 to 85.5 kDa (Table ). The average Mw was 73.8 kDa (18% RSD) for Mid MW Silk. Mid MW Silk produced on the Benchtop had the lowest Mw. The polydispersity range for Mid MW Silk was 1.445 to 1.799. The dissolution time is a critical factor in determining the Molecular Weight of High Molecular Weight Silk (High MW Silk). The weight-average molecular weight range for High MW Silk was 67.6 to 95.1 kDa with the longer dissolution time producing a material with lower Mw and higher PDI (Table ). The PDI was 1.566 and 1.39 for the longer and shorter dissolution times, respectively. Analytical Methods Analysis was performed with a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm with guard column connected to an Agilent 1260 Infinity II HPLC system with Wyatt LS and RI detectors (Table ). Table 97. HPLC Instrument Configuration Sa Sa Q C U L RI

The mobile phase used for the analysis was a solution of 12.5 mM Na₂HPO₄, 100 mM NaCl titrated to a final pH of 7.0 ± 0.2 with H3PO4. Before installing mobile phase on the HPLC, the solvent was filtered through a 0.22 μm PES filter into a clean glass bottle. A summary of critical method parameters is described in Table 98. Table 98. SEC-MALS Critical Method Parameters C Ta Fl ^C U R A ¹I

Data Analysis All silk samples were processed in software ASTRA 7.3.2 following vendor recommended procedures. Reportable values of Mw, Mn, and PDI were derived from software ASTRA 7.3.2. Additional data analysis and production of figures were performed in GraphPad Prism 9 version 9.5.1 and Adobe Illustrator version 27.5. Tables Table 99. Summary of Mw and PDI for Low, Mid, and High Molecular Weight Silk _L _M _M M M M _M _M _M

_W _W M M M M M

Table 100. Summary of Molecular Weight Ranges for Low, Mid, and High Molecular Weight Silk _L M M M M M ^M _M ^M W W _M

_M

Example 43: Absolute Weight Average Molecular Weight and Polydispersity of Low Skid silk/ modified polypeptide compositions and Mid Skid silk/modified polypeptide compositions by Size Exclusion Chromatography-Multi-Angle Light Scattering (SEC- MALS) Development of Mid Skid silk/modified polypeptide compositions The development of modified polypeptide compositions of Low and Mid Skid Silk have been previously discussed as the generation of Low and Mid Skid Silk and the subsequent isolation of their modified polypeptide compositions. Summary of Methodologies to Measure Molecular Weight This document discusses the measurement of molar mass moments, specifically Mw, by SEC-MALS. Molar mass can be used interchangeably with the term “molecular weight”. For the sake of clarity, molar mass will be used in this document. Measuring Molar Mass Moments by SEC-RI The method previously used for molar mass determination was SEC-RI. The following section is intended to describe the differences of the two methods and how both can exist in future fillings. As both methods produce a reported value of weight-averaged molecular weight (Mw), it is recommended that the Mw values be redefined as “absolute Mw” for SEC- MALS and “relative Mw” for SEC-RI. Alternatively, the values derived from SEC-RI can be referred to as Mw without the additional qualifier (“relative”) for the sake of continuity between the fillings. Summary: SEC, “size exclusion chromatography”, is a mode of chromatographic separation and, on its own, cannot provide an absolute molar mass. Instead, SEC can provide a relative molar mass of a protein (or polymer) against a calibration curve of standard; this conventional calibration method provides a relative molar mass. SEC is often paired with a RI detector which is concentration-sensitive and molar-mass-insensitive. Additional Information: With SEC, molecules are separated by hydrodynamic size (larger molecules having a shorter retention time than smaller molecules) which is correlated to molar mass. Herein, the retention time of the protein of interest is related to the calibration curve comprised of proteins or polymers of known molar mass. The caveat is that the unique structure or shape of a protein will impact the retention time in SEC; this may lead to erroneous reported molecular weights especially if the protein of interest differs significantly from the calibration curve. However, this method is commonly used as an industry-standard as LS detectors and such SEC-MALS has not been universally adopted as the singular molecular weight determination method. Measuring Molar Mass Moments by SEC-MALS This document reports molecular weight and polydispersity as measured by SEC- MALS for fractionated silk. SEC-MALS produces an absolute weight averaged molar mass (Mw) measurement as compared to the relative molar mass measurement produced by a conventional calibration method such as SEC-RI. Two detectors were used in the calculation of molar mass moments by SEC-MALS in this document: a refractive index (RI) detector and light scattering (LS) detector. RI detector provides the concentration of the protein. LS detector provides the weight-average molar mass (Mw) of the protein directly and absolutely; the intensity of scattered light is directly proportionate to the Mw of the molecule. LS is the most widely used technique for determining Mw. Calculation of Molar Mass Moments The calculation of molar mass moments uses the following variables: n_i, M_i, and c_i. M_i, and c_i are directly measured by SEC-MALS. Note that the subscript “i” indicates that the value is calculated at each slice of peak of interest. ● n_i is the number of molecules ● M_i is the molecular mass of the molecules (measured by LS detector) ● c_i is the concentration of material as measured by the concentration detector (measured by RI detector) Number-average molar mass, Mn, is related to an arithmetic mean where the total mass is divided by the number of molecules.

For the weight-average molecular mass, Mw:

Calculation of Polydispersity Index (PDI) The PDI is the ratio of Mw and Mn as calculated by the program ASTRA. A macromolecule is considered to be polydisperse if the PDI > 1.05.

Results Low Skid silk/modified polypeptide compositions isolated by charge and size, AS77-AS81 To isolate AS77-AS81 Low Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-eluate. Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH 8.0. The silk was centrifuged and filtered before loading to the Q-Sepharose column, to remove any pre-formed aggregates. The silk compositions were loaded onto the Q-Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl₂). The eluted fractions were pulled together and are referred to as the Q-elution fraction. The Q-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions. Low Skid silk preparation solutions have a characteristic yellow hue. The Q-elution fraction has a strong yellow hue, while the flowthrough fraction is transparent, and tends to self-assemble very quickly. The Q-elution silk compositions that are fractionated by size exclusion also had a yellow hue. When silk formulations AS77-AS81 are analyzed with an analytical SEC-MALS (see materials and methods) with HPLC, the weight average molecular weight range of the 118.2 to 61.1 kDa with AS77 having the highest Mw and AS81 having the lowest Mw (Figure AL and Table W). There was not a strong trend relating the PDI and fraction number but all are polydisperse (PDI > 1.05). The PDI of unfractionated LS skid was significantly higher than the PDI of AS77-81 indicating the unfractionated silk has a more diverse peptide population. Low Skid silk/modified polypeptide compositions isolated by size: AS82-AS89 To isolate AS82-AS89 Low Skid silk/modified polypeptide compositions were fractioned using HiLoad 26/600 Superdex 200 pg size exclusion chromatography column. Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH 8.0. The silk was centrifuged and filtered before loading to the HiLoad 26/600 Superdex 200 pg column, to remove any pre-formed aggregates. The silk compositions were fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions. When silk formulations AS82- AS89 are analyzed with an analytical SEC-MALS (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average Mw and PDI values. Distinct populations were isolated by size, by fractionating Low Skid silk/modified polypeptides by preparatory scale size exclusion chromatography by FPLC; these fractions are AS82-AS89. A high-resolution separation of five silk compositions was achieved– AS82, AS83, AS84, AS85, and AS86. These silk compositions differ from one another by their average size; AS82 is the largest (100.9 kDa) and AS86 is the smallest of this set (51.5 kDa) (Figs.117A- 117B and Table 104). Three additional fractions, AS87-AS89, were less resolved as the resolution of the Superdex 200 is not optimal for separating proteins smaller than 44 kDa. Fractions AS87, AS88, and AS89 were significantly smaller than AS82-AS86 with Mw of 18.2, 18.5 and 11.1 kDa, respectively. This higher polydispersity of AS87-AS89 is indicative of the reduced resolution and in agreement with the size measured by DLS. Low Skid silk/modified polypeptide compositions isolated by charge, hydrophobicity, and size: AS90-AS94 and AS95-AS100 To isolate AS90-AS100 Low Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following hydrophobic interactions (HIC) chromatography, followed by HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-HIC-eluate (AS90-94) and of the Q-HIC- flowthrough (AS95-100). Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH 8.0. The silk was centrifuged and filtered before loading to the Q- Sepharose column, to remove any preformed aggregates. The silk compositions were loaded onto the Q-Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl₂). The eluted fractions were pulled together and are referred to as the Q-elution fraction. The Q- flowthrough fraction is colorless and tends to aggregate. The Q-elution was further fractionated by using a Butyl ImpRes column, which separates polypeptides based on hydrophobicity. The chromatography was performed in the presence of 300 mM ammonium sulfate, to expose hydrophobic regions within the silk polypeptides. The highly charged flowthrough fraction (Q-HIC-flowthrough) was collected for further fractionation by size exclusion chromatography. The more hydrophobic, bound silk peptides were eluted using 50 mM Tris, pH 8.0 in the absence of ammonium sulfate, to reverse the exposure of the hydrophobic regions in silk polypeptides, which results in their release from the Butyl ImpRes column. The Q-HIC-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Table 104 and Figs.119A- 119B). The fractions that were isolated are AS90-AS94. Then, the Q-HIC-flowthrough fraction was fractionated as well by the HiLoad 26/600 Superdex 200 pg, resulting in the generation of AS95-AS100. The Q-HIC Elution fraction is composed of higher-molecular-weight peptide composition, while the silk peptides that compose the Q-HIC Flowthrough fraction are eluted later, indicating smaller molecular weights (Table 105, Figs.119A- 119B and 120A- 120B). Unfractionated Low Skid silk has an average Mw of 41.2 kDa, indicating that most of the peptide population tends to have lower molecular weight than fractions AS90-AS94 (Table 105). Additionally, the PDI of unfractionated silk is significantly higher than the resultant fractions supporting that unfractionated Low Skid silk is composed of a much diverse polypeptide population compared to fractions AS90-AS100 (Table 105). Mid Skid silk/modified polypeptide compositions isolated by charge and size: AS101- AS105 To isolate AS101-AS105, Mid Skid silk/modified polypeptide compositions were fractioned using anion exchange chromatography (Q-Sepharose chromatography), following HiLoad 26/600 Superdex 200 pg size exclusion chromatography of the Q-eluate. Prior to chromatography, Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH 8.0. The silk was centrifuged and filtered before loading to the Q-Sepharose column, to remove any preformed aggregates. The silk compositions were loaded onto the Q- Sepharose column, and the flowthrough fraction was collected. The negatively charged silk compositions were eluted using high salt buffer (50 mM Tris, 500 mM CaCl2). The eluted fractions were pulled together and are referred to as the Q-elution fraction. The Q-elution was further fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions. Mid Skid silk preparation solutions have a characteristic yellow hue. The Q-elution fraction has a strong yellow hue, while the flowthrough fraction is transparent, and tends to self-assemble very quickly. The Q-elution silk compositions that are fractionated by size exclusion also had a yellow hue. When silk formulations AS101-AS105 are analyzed with an analytical SEC-MALS (see materials and methods) with HPLC, each of the silk formulations demonstrates a unique average Mw and Polydispersity (PDI) value (Figs.121A- 121B and Table 106). In general, AS101 has the highest Mw (101.5 kDa), while AS105 has the lowest Mw (48.9 kDa). Unlike Mw, there was no clear trend in PDI as related to fraction number. Unfractionated Mid Skid silk has an average Mw of 81.9 kDa, indicating that most of the peptide population tends to have lower molecular weight than fractions AS101-AS105. The polydispersity of unfractionated Mid Skid silk is 1.697 – significantly higher than the values of fractions AS101- AS105. This indicated that the unfractionated Mid Skid silk is composed of a much diverse peptide population compared to fractions AS101-AS105, where the majority of the peptide populations have lower molecular weight. Note: it has been observed that Mid MW Silk (and subsequent fractions) will aggregate over time. This is also corroborated by the SAF assay. The samples were tested a few months after fractionation which is reflected in the Mw and PDI values reported by the SEC-MALS assay as compared to the SEC-RI assay Mid Skid silk/modified polypeptide compositions isolated by size: AS106-AS111 To isolate AS106-AS111 Mid Skid silk/modified polypeptide compositions was fractioned using HiLoad 26/600 Superdex 200 pg size exclusion chromatography column (Figs.114 & 117A-117B). Tris was added to the silk preparations to a final concentration of 50 mM Tris–HCl, pH=8.0. The silk was centrifuged and filtered before loading to the HiLoad 26/600 Superdex 200 pg column, to remove any preformed aggregates. The silk compositions were fractionated by the HiLoad 26/600 Superdex 200 pg, where the largest polypeptide compositions were eluted first, and each following fraction had a population of lower molecular weight of silk compositions (Figs.119A-119B & 120A-120B). Mid Skid silk preparation solutions have a characteristic yellow hue, and the fractionated silk compositions had a light- yellow hue. When silk formulations AS106-AS111 are analyzed with an analytical SEC column (see materials and methods) with HPLC, each of the silk formulations demonstrates a different average molecular weight, and a different Polydispersity (PDI) value (Table 107 and Figs.122A- 122B). In general, AS106 has the highest molecular weight (204.4 kDa), while AS111 has the lowest molecular weight (67.4 kDa). There is not a strong trend between PDI and fraction number. Unfractionated Mid Skid silk has the highest PDI, 1.697, indicating a broad and diverse peptide population sizes. Note: it has been observed that Mid MW Silk (and subsequent fractions) will aggregate over time. This is also corroborated by the SAF assay. The samples were tested a few months after fractionation which is reflected in the Mw and PDI values reported by the SEC-MALS assay as compared to the SEC-RI assay. Analytical Methods Analytical SEC-MALS Analysis was performed with a PolySep GFC P-4000 LC Column, 300 mm x 7.8 mm (Phenomenex, Part No. CH0-9229) with guard column connected to an Agilent 1260 Infinity II HPLC system with Wyatt LS and RI detectors (Table 101). Table 101. HPLC Instrument Configuration

Sa Sa Q C U L RI

The mobile phase used for the analysis was a solution of 12.5 mM Na₂HPO₄, 100 mM NaCl titrated to a final pH of 7.0 ± 0.2 with H3PO4. Before installing mobile phase on the HPLC, the solvent was filtered through a 0.22 μm PES filter into a clean glass bottle. A summary of critical method parameters is described in Table 102. Table 102. SEC-MALS Critical Method Parameters C Ta Fl C U

R A ¹

Data Analysis All silk samples were processed in software ASTRA 7.3.2 following vendor recommended procedures. Reportable values of Mw, Mn, and PDI were derived from software ASTRA 7.3.2. Additional data analysis and production of figures were performed in GraphPad Prism 9 version 9.5.1and Adobe Illustrator version 27.5. Fractionated Low Skid Silk Unfractionated Low Skid Silk had a Mw of 41.2 and PDI of 1.575. Tables Table 103. Summary of Mw and PDI for fractionated Low Skid Silk by Q-SEC (AS77-AS81)

Table 104. Summary of Mw and PDI for fractionated Low Skid Silk by SEC (AS82-AS89)

Table 105. Summary of Mw and PDI for fractionated Low Skid Silk by Q-HIC-SEC (AS90- AS100) (

Table 106. Summary of Mw and PDI for fractionated Mid Skid Silk by Q-SEC (AS101-AS105)

Table 107. Summary of Mw and PDI for fractionated Mid Skid Silk by SEC (AS106-AS111)

Example 44: Basecoat and Topcoat Components for Coating System Below are examples of the amount of various products that may be included in the topcoat and basecoat in accordance with a coating system described herein. Table 108. Basecoat and Topcoat Grams per sq. ft. C L5 ba L0 top

Example 45: Cellulose Stabilized Silicone Hand Modifier in a Semi-Polar Solvent Described herein is an emulsification of a silanol/amino-polysiloxane mixture to prevent moisture separation and discoloration in leathers after milling as part of the leather finishing process. The L0822 topcoat in the L1 finishing system while delivering superior CFR performance, is lacking in hand feel. While there exist current products on the market such as SIL/T99, CERAL FI/62, and many other silicones, they are normally used for polyurethane topcoats. When they are used in a cellulose based topcoat, they cause discoloration and optical defects. Because of this, another silicone-based hand modifier product is needed to deliver the similar “silky” hand feel from the other products without discoloration happening after milling. There are two main causes of this incompatibility of current silicone hand modifiers available on the market and the L0822 topcoat product. The first issue is the solvent-based nature of the L0822 topcoat product, its inherent hydrophobicity translates to poor combability with water-borne silicone emulsions used for commonly utilize polyurethane topcoats. The second issue arises from the nature of the silicone used in the currently available hand modifier products. These silicones are typically polydimethylsilicone based, or silanols which are not compatible with cellulose based films. These two issues cause discoloration and other optical issues in topcoat finishes after milling. To solve this, a mixture of amino-functionalized silicones was determined to be the optimal polymeric mixture to deliver a desirable hand feel without discoloring the topcoat. In particular, out of the amino functionalized polysiloxanes tested, aminoethylaminopropyl-based polysiloxanes performed best. While some of these were available in water dispersions, only the solvent compatible versions were able to deliver the performance required. However, the instability of this mixture of aminoethylaminopropyl-based polysiloxanes when exposed to air for an extended period of time combined with its intolerance for temperature changes required further stabilization. The commercially available product requires nitrogen blanketing to remain shelf stable for extended periods of time, or the use of toxic highly non-polar organic solvents to remain in dispersion. This cellulose stabilized emulsion was developed to give an air stable and temperature stable hand modifier which can be dispersed in more polar organic solvents and is capable of delivering a “silky” hand feel without causing discoloration in the L0822 topcoat. Preparation of A971 Hand Modifying Agent For The L1 Cellulose Based Finishing System To start, 200 kDa Ethyl Cellulose (EC) is dissolved into 1-methoxy-2-propanol (MP) at a concentration of 6.07% solid mass. This solution is mixed with an overhead mixer and a Cowles blade. After the ethyl cellulose is fully dissolved into the solvent, Silamine DG-22 supplied by Siltech Corporation (DG-22) is added in to the solution in a ratio of 1:7 DG-22 to EC/MP solution. The final concentration of all components should be 12.5% DG-22, 5% EC, and 82.5% MP. The solution is then mixed with the Cowles blade until desired viscosity is reached (between 2000cP and 3000cP at room temperature). In the topcoat, the hand modifier can be added at a concentration between 1% and 8%. However, as will be seen in the data below, an optimal concentration of 4% delivers the best hand feel without affecting topcoat performance. As can be seen in Table109, as the concentration of hand modifier in the topcoat increases there is no change in degree in discoloration (∆∆E). Furthermore, the increase in hand modifier does improve hand feel. At 4% it gives the optimal “silky” equivalent of other available products (SIL/T99, BYK, and Ceral FI/62). In terms of finishing performance, after processing there does not appear to be any effect on the Bally Flex, but as the concentration of hand modifier increases the CFR does improve. Table 109. The performance of hand modifier in the topcoat as a functional of concentration (0-4% by mass) in terms of discoloration, hand feel, and leather performance after milling. The concentration curve was also compared to the other hand modifier products on the market. C 0% ) 1% ) 2% ) 4% ) 1% 1% 1% C 0% ) 1% ) 2% ) 4% ) 1% 1% 1%

C 0% ) 1% ) 2% ) 4% ) 1% 1% 1%

The optimal concentration of DG-22 and EC added to the hand modifier to produce a stable topcoat without compromising the performance was determined to be a 5 to 2.5. The final hand modifier total solid mass should be of 17.5% in the hand modifier. In terms of cellulose concentration in the hand modifier, as can be seen in Table B, increasing the concentration of ethyl cellulose does improve the discoloration after milling. However, it also increases the viscosity of the hand modifier solution as can be seen in Table 5. In particular, at a concentration of 8.5% EC the solution has such a high viscosity it will not disperse into the topcoat solution within an hour of overhead mixing. In terms of hand feel, the concentration of ethyl cellulose had no effect on the hand feel of the finished product. Table 110. The performance of hand modifier in the topcoat as a functional of cellulose concentration in the hand modifier (2.5-8.5% by mass of hand modifier). NOTE, the sample containing 8.5% ethyl cellulose had such a high viscosity it was unable to fully dissolve in the topcoat. Co 1% _(Di 1% 1% 1% Co 1% (Di 1% 1% 1%

In terms of the concentration of DG-22 in the topcoat, as can be seen in Table 111, changing the concentration of DG-22 in the topcoat has no effect on the degree of discoloration. However, decreasing the concentration of DG-22 does negatively impact the hand feel of the finished product, which makes intuitive sense, because DG-22 is the active component. This means the concentration of hand modifier in the topcoat must be scaled to the concentration of DG-22 in the hand modifier to deliver the desired hand feel for the final product. As can be seen in Table 112, when scaled proportional to the concentration of DG- 22, the desired hand feel is reached. Table 111. The performance of hand modifier in the topcoat as a functional of silicone concentration in the hand modifier (between 0 and 25% DG-22) Co 1% 1% 1% 0% Co 1% 1% 1% 0% Co 1% 1% 1% 0%

Table 112. The performance of hand modifier in the topcoat as a functional of silicone concentration in the topcoat. Scaled for total final mass of DG-22 in the topcoat. C 1% 1% 1% 2% 4% 8% 4% 8% 16 C 1% 1% 1% ^2% _4%

8% 4% 8% 16 C 1% 1% 1% 2% 4% 8% 4% 8% 16

Table 113. The viscosity of the hand modifier solution as a function of silicone and ethyl cellulose concentration. DG-22 EC Concentration Concentrati EC Concentration C 50% 8.5% 50% 7.5% 50% 5% 50% 2.5% DG-22 Concentration 50% 5% 25% 5% 12.5% 5% 6.25% 5%

In terms of shelf-life stability, when changing the concentrations of DG-22 and EC, the optimal concentrations in the hand modifier are 12.5% DG-22 and 5% EC. This formulation delivers a stable and clear solution after both 2 weeks at room temperature (Table 114) while delivering more DG-22 to the topcoat than a 6.25% DG-22 formulation. From an EC standpoint 5% EC stabilizes the solution short term better than 2.5% while not becoming hazy or drastically increasing the viscosity (as can be seen in Table 114 and Table 113). At room temperature, after one month no separation occurred in the hand modifier solution, however, after only two days the DG-22 product on its own separated out without nitrogen blanketing. Furthermore, after one week at room temperature the DG-22 product formed an unusable gel while no change could be recorded in the hand modifier. Under heat accelerated aging, the hand modifier remained stable and clear after 32 days at 40°C while DG-22 on its own gelled out after only 4 days. In terms of variations in viscosity, at room temperature the viscosity of the hand modifier solution decreased by 5.8% and at 40°C it decreased by 9.9% after 2 weeks. Table 114. Short term shelf life stability data of the varying concentrations of EC and DG-22 in the hand modifier to determine the optimal ratio for stability. Co

Table 115. Long term shelf-life stability data of the hand modifier compared to the Silamine DG-22 silicone on its own, evaluated at both room temperature and at an accelerated aging temperature of 40°C. Sa 1 2 || 1 2 || 1 1

When tested for temperature stability, the utilization of the methoxypropanol solvent in conjunction with the ethyl cellulose emulsion stabilizer are able to increase stability. At higher temperatures, 50°C, the addition of methoxypropanol on its own has no bearing on either the solution stability or the performance of the auxiliary in the topcoat. Both with and without methoxypropanol, at extreme temperatures (10°C and 50°C) the solution gels or separates out making it poorly compatible with dispersion in the topcoat. The addition of ethyl cellulose appears to preserve both the auxiliary stability and performance on the leather, in particular hand feel and even appearance. At both a low concentration (2.5% EC) and high concentration (5% EC) added to the auxiliary a phase change is prevented (gelation or separation) or optical change (haziness). Table 116. Overnight freezing and heating data for varying combinations of DG-22, EC and MP.

Silamine DG-22 was chosen as the main form of silicone because of it’s minimal degree of discoloration after milling. As can be seen in Table 117, after milling, it delivers the smallest degree of discoloration of all amino functionalized silicones. Table 117. Comparison in Performance to Alternative Silicones for use as a hand modifier. Si 1% 1% 1% 1%

1% 1% 1% 1% 1% 1% 1% 1%

Example 46: Plasticizer System for Activated Silk™ L1 Biofinishing System A polyurethane dispersion (PUD) can be in a solvent system as plasticizer to prevent cracking in leathers after milling as part of the leather finishing process. Milling is a key and a common practice at tanneries to soften leather after finishing is completed. Milling is a mechanical softening process in which leather is tumbled upon in a dry drum where temperature and humidity are controlled. Milled leather usually gives better feel/touch and easy processibility for certain applications. Although an acceptable softness depends on the final application, the minimum viable products (MVP) for the Activated Silk™ L1 Biofinishing system is set to 5 hours; achieving 10 hours of milling is highly recommended. The Activated Silk™ L1 Biofinishing system have not shown sufficient softening due to the rigidity of a cellulose based topcoat that was designed to provide dry and wet rub resistance. Therefore, a plasticizer(s) or a plasticizing material is necessitated to deliver sufficient softening after milling. Numerous conventional plasticizers as a single component or multiple components have been tested as the film-casts and on the leather at various concentrations (1.25-20% relative to the topcoat’s solid amount) (Table 118) with 2.5% topcoat (Hereafter, the percentages are described as relative to the topcoat’s solid amount). Although they form soft films when casted, they failed during milling. Failing is defined as cracks, white lines, dot or sometimes discoloration on the leather surface (Fig.128). At lower concentrations (1.25-5%) of the plasticizers, the coating on the leather is still stiff and it starts forming cracks and lines after milling. However, at higher concentrations (10-20%) of the plasticizers, the coatings can become too soft and the films lose their integrity, and sometimes cannot form a film. The coatings could also easily delaminated or be torn apart after milling. Besides, cracks, lines, or delamination; use of high amount of plasticizer could lead to a very oily finish which is not acceptable in some applications. In addition, other performance tests such as color fastness-to-rubbing, flexing, tape or water drop tests must be delivered at desired levels. Table 119 shows some examples of conventional plasticizers and the systems at various concentrations with low performance. Table 118: Conventional plasticizers with low performance at/after milling. RI _S Gly rici ^But Me rici Me ^Cet n-B rici Gly (ac rici Pro rici

BE Di( gly dib Die gly dib Pol gly dib Pol gly dib Gly _trib C1 ben Pro gly dib

Table 119. Some examples of low performance conventional plasticizers and the systems at various concentrations. ^Co Ca Ca Ca Iso Gly Ep Dii Tri Ac Ca Di(

Besides conventional plasticizers, PUDs traditionally used for water-borne systems were also evaluated. There are three main types of PUDs: Polyester, polyether, and polycarbonate. Polyurethanes are copolymers consisting of soft and hard segments. The soft segment giving flexibility and elasticity is typically a polyether or polyester polyol while the hard segment giving strength to the polymer is made of a diisocyanate and chain extender. It has been shown that the type and content of the soft segment play a crucial a role on the crystallinity of polyurethane. Since the L1 topcoat is delivered in organic solvents, the foremost requirement for a PUD to be considered as a candidate is that it must be soluble/dispersible and sprayable in the solvent system. Some PUDs are not soluble/dispersible/sprayable or sprayable even at limited concentrations. After meeting the first requirement in the topcoat solvent, some PUDs could fail the milling process (Table 120). Various PUDs were tested at 0.5-2.5% solid concentrations. With the available information about the type of PUD from the suppliers, the general types of failed PUDs are polyester, polycarbonate, or blends of polyester and/or polycarbonate. It is noted that while polycarbonate-based PUDs have great water and chemical resistance, they have limited flexibility and does not pass milling. A polyether-based PUD gives more flexibility compared to a polyester-based PUD by suppressing the crystallization of the polymer due to the flexible ether-linkages. Moreover, dispersing a PU in water can be carried out by either using external emulsifiers or incorporating emulsifying segments into the PU backbone. The latter can be provided by polyether groups since they possess ionic and hydrophilic regions which gives high stability to dispersions compared to non-polyether derivatives. Also, polyether-based PUDs have excellent hydrolysis resistance compared to that of polyester analogue since ester groups are susceptible to hydrolysis. Activated Silk™ L1 Biofinishing system is a composite system utilizing a polyether- based PUD and Activated Silk™ as a basecoat and a cellulose based topcoat. It has been previously observed that polyether-based PUD/Activated Silk™ solution has high compatibility to leather and the cellulose-based topcoat. While PUDs are water-based and they typically offer low color fastness-to-rubbing performance and fail water drop tests, the synergy of the polyether-based PUDs with Activated Silk™ L1 Biofinishing system’s composite offers a high performing system at low concentration solids enabling thin applications to improve haptics. Table 120: PUD plasticizers PU Var Im Im Im Im Im Im Im Im Im Jon WT WT WT WT Aq PU PU Ha Ha Ha Bio PU Hei Hei

How to prepare a plasticizing agent for the L1 biofinishing system: Dilute the 5% Activated Silk™ L1 biofinishing system topcoat (L0822) with an alcohol (ethanol, isopropanol, methoxypropanol, etc.) down to 2.5%. To this solution, a polyether- based PUD or polyether-based PUD blends are added at a concentration between 0.5 – 2.5%. The solution is then mixed with the Cowles blade, a paddle or a stir bar depending on the batch size until homogenous. Table 121. The topcoat performances of polyether-based PUDs along with milling results. _PU Per 1.2 2.5 10 0.6 1% 1.2 2.5 10 2.5 10

Blend of polyether-based PU to provide different haptics: Another unequivocally desired task for a coating is to achieve some haptic properties such as a soft touch. The concept of soft touch is usually defined as the processing of signals detected by the neural receptors in the skin upon contact with a surface because of the generation of the frictional forces in-between. Since the measurement of the softness of coatings by an instrument is challenging, the most common technique is still to assess the coating personally by hand touch of individuals. Soft touch features of the polyether-based PUDs plasticizers in the Activated Silk™ L1 biosystem were also investigated after milling. It was noticed that not all the polyether-based PUDs give the same touch (Table E). For instance, while HEIM 3317 gives the softest feel, PU 2450 gives the lowest. It can be speculated that a parameter called as “100% modulus” for the films might be the reason (limited data from the suppliers).100% modulus is defined as a force required for short elongation. The lower the 100% modulus, the softer the feeling. Blending can also help improving the softness of the lowest ones synergistically. Adding a small amount of the softest one into the lowest soft one (PU 2450) can improve the touch of the lowest one greatly. For example, blend of Biopur 5000 and HEIM 3317 gives a smoother touch compared to Biopur 5000 alone. Another finding was that the processing conditions have an impact on the softness. As the ironing temperature increases the feel changes from a dry-smooth to soft-smooth. Table 121. Haptics of some PUDs with the topcoat at various processing conditions. ^PU PU Bio Hei Bio PU

The efficacy of this invention is that the performance of polyether-based PUDs and blends even at low concentrations is superior to that of the conventional plasticizers and can provide a range of haptics via different processing conditions. Example 47: Matting Agent 1-Part Matting Agent System This is a change from the formulation A in a few ways: • One part formulation • Addition of hydrophilic fumed silica for stability Without wishing to be bound by any particular theory, it is believed that replacement of Triacetin with Diacetin makes it more miscible such that it can be made into a one part. C A 3 A R D D A W T

Example 48: Activated Silk™ Paper Release Transfer Leather Figures 129A and 129 B illustrates the process for forming a pattern on leather using paper release. Biodegradable chemistries are used for pre-skin, skin, basecoat and topcoat. Release paper is textured and acts as a mold to final desired pattern. The pattern is carried through the basecoat and topcoat layer. As shown in Fig.129A, a “Pre-skin” layer is applied to leather and the “Skin” layer is applied to leather and dried. Both of these can be applied via spray or roller coated. Then the pre-skin and skin layers are laminated together using temperature and pressure via a rotopress. The release paper used for applying the L1 basecoat and then dried. Then the L1 topcoat is applied by spraying or rollercoater and dried. A basecoat/ topcoat composition is then formed. A rotopress can be used as needed in any of the steps above. As shown in Fig.129B, an optional pre-ground, ground and/or adhesive layer can be applied to leather via spray or roller coated. Then the “Basecoat” layer is applied to release paper via spray or roller coated. Release paper is optionally embossed with a relief pattern. Then the release paper is applied with Basecoat, via a roller, e.g., via rotopress as needed. The release paper can then be removed for reuse. The optional embossing / relief pattern is transferred in a durable fashion to the top of the Basecoat layer. Topcoat is then applied via spray or rollercoater. Basecoat/topcoat composite is formed. A rotopress can be used as needed. The optional embossing / relief pattern is retained in a durable fashion to the top of the Topcoat layer. The Activated Silk™ Topcoat layer is lower in solids concentration than a traditional topcoat (1.5 – 3% vs.15- 35%). When applied to Activated Silk™ L1 basecoat, it creates a composite. Both features enable better flexibility and ultimately adhesion to the below layers (see Figs 131A and 131B). Example 49: Alternative Activated Silk™ Paper Release Transfer for Large Defect or Snuff Leather Figure 130 illustrates the process for forming a pattern on leather for a large defect or snuff leather. Biodegradable chemistries can be used for stucco, pre-skin, skin, basecoat and topcoat. Release paper is textured and acts as a mold to final desired pattern. The pattern is carried through the basecoat and topcoat layer. For large defect or snuff leather that needs grain rebuild or correction, stucco can be applied prior to the skin layer. Both of these can be applied via spray or roller coated. Then the pre-skin and skin layers are laminated together using temperature and pressure via a rotopress. The release paper is used for applying the L1 basecoat which can then be dried. Then the L1 topcoat is applied by spraying or rollercoater and dried. A basecoat/ topcoat composition/composite is then formed. A rotopress can be used as needed in any of the steps above. Laminated skin (Pre-skin and skin) fills in defects on the leather. The Activated Silk™ Topcoat layer is lower in solids concentration than a traditional topcoat (1.5 – 3% vs.15- 35%). When applied to Activated Silk™ L1 basecoat, it creates a composite. Once applied to Activated Silk™ L1 basecoat, it creates a composite as previously shown in Example 31 (SEM images of leather samples tested with BSE (SE2) . Both features enable better flexibility and ultimately adhesion to the below layers (see Figs 131A and 131B). Table 122. Application Rates for Substrates St S s

Table 132. Optional Ingredient List for Each Layer Discussed in Examples 48 and 49 Ba To Sk So

All patents, patent applications, and published references cited herein are hereby incorporated by reference in their entirety. While the methods of the present disclosure have been described in connection with the specific embodiments thereof, it will be understood that it is capable of further modification. Further, this application is intended to cover any variations, uses, or adaptations of the methods of the present disclosure, including such departures from the present disclosure as come within known or customary practice in the art to which the methods of the present disclosure pertain. REFERENCES Abdel-Naby, W., Cole, B., Liu, A., Liu, J., Wan, P., Guaiquil, V. H., Schreiner, R., Infanger, D., Lawrence, B. D., & Rosenblatt, M. I. (2017). Silk-derived protein enhances corneal epithelial migration, adhesion, and proliferation. Investigative Ophthalmology and Visual Science, 58(3), 1425–1433. https://doi.org/10.1167/iovs.16-19957 Fitsialos, G., Chassot, A.-A., Turchi, L., Dayem, M. A., LeBrigand, K., Moreilhon, C., Meneguzzi, G., Buscà, R., Mari, B., Barbry, P., & Ponzio, G. (2007). Transcriptional signature of epidermal keratinocytes subjected to in vitro scratch wounding reveals selective roles for ERK1/2, p38, and phosphatidylinositol 3-kinase signaling pathways. The Journal of Biological Chemistry, 282(20), 15090–15102. https://doi.org/10.1074/jbc.M606094200 Huang, C., Rajfur, Z., Borchers, C., Schaller, M. D., & Jacobson, K. (2003). JNK phosphorylates paxillin and regulates cell migration. Nature, 424(6945), 219–223. https://doi.org/10.1038/nature01745 Klemke, R. L., Cai, S., Giannini, A. L., Gallagher, P. J., de Lanerolle, P., & Cheresh, D. A. (1997). Regulation of cell motility by mitogen-activated protein kinase. The Journal of Cell Biology, 137(2), 481–492. https://doi.org/10.1083/jcb.137.2.481 Körner P. Hydrothermal Degradation of Amino Acids. ChemSusChem. 2021;14(22):4947–57. Lee, M.-H., Koria, P., Qu, J., & Andreadis, S. T. (2009). JNK phosphorylates beta- catenin and regulates adherens junctions. FASEB Journal^: Official Publication of the Federation of American Societies for Experimental Biology, 23(11), 3874–3883. https://doi.org/10.1096/fj.08-117804 Martínez-Mora, C., Mrowiec, A., García-Vizcaíno, E. M., Alcaraz, A., Cenis, J. L., & Nicolás, F. J. (2012). Fibroin and sericin from Bombyx mori Silk stimulate cell migration through upregulation and phosphorylation of c-Jun. PLoS ONE, 7(7). https://doi.org/10.1371/journal.pone.0042271 Onder, O. C., Batool, S. R. & Nazeer, M. A. Self-assembled silk fibroin hydrogels: from preparation to biomedical applications. Mater. Adv.3, 6920–6949 (2022). Park, K.-J., Jin, H.-H. & Hyun, C.-K. Antigenotoxicity of peptides produced from silk fibroin. Process Biochem.38, 411–418 (2002). Pearson, G., Robinson, F., Beers Gibson, T., Xu, B. E., Karandikar, M., Berman, K., & Cobb, M. H. (2001). Mitogen-activated protein (MAP) kinase pathways: regulation and physiological functions. Endocrine Reviews, 22(2), 153–183. https://doi.org/10.1210/edrv.22.2.0428 Ruiz-Lozano, R. E., Hernandez-Camarena, J. C., Loya-Garcia, D., Merayo-Lloves, J., & Rodriguez-Garcia, A. (2021). The molecular basis of neurotrophic keratopathy: Diagnostic and therapeutic implications. A review. In Ocular Surface (Vol.19). Elsevier Inc. https://doi.org/10.1016/j.jtos.2020.09.007 Sah, M. K. & Pramanik, K. Regenerated Silk Fibroin from B. mori Silk Cocoon for Tissue Engineering Applications. Int. J. Environ. Sci. Dev.404–408 (2010) Stupack, D. G., Cho, S. Y., & Klemke, R. L. (2000). Molecular signaling mechanisms of cell migration and invasion. Immunologic Research, 21(2–3), 83–88. https://doi.org/10.1385/IR:21:2-3:83 Vepari, C., & Kaplan, D. L. (2007). Silk as a biomaterial. Progress in Polymer Science (Oxford), 32(8–9), 991–1007. https://doi.org/10.1016/j.progpolymsci.2007.05.013

Claims

1. An article comprising a substrate and a coating, wherein the coating comprises a base layer comprising a first polymeric macromolecular species or polymer and a top layer comprising a second polymeric macromolecular species or polymer, wherein the base layer comprises mechanically engineered topographical features on a surface opposite to the substrate, wherein the engineered topographical features have width and/or depth dimensions on a scale of from about 0 pm to about 250 pm. wherein a portion of the base layer and a portion of the top layer form a composite layer which substantially represents and/or retains the topographical features of the base layer.

2. The article of claim 1, further comprising one or more additional layers disposed between the substrate and the base layer, the additional layers selected from a preground layer, a ground layer, and an adhesive layer.

3. The article of claim 2, wherein the base layer topographical features are substantially different from any non-engineered topographical features of the substrate, the preground layer, the ground layer, and/or the adhesive layer.

4. The article of claim 2 or 3, wherein the composite layer topographical features are substantially different from any non-engineered topographical features of the substrate, the preground layer, the ground layer, and/or the adhesive layer.

5. The article of any one of claims 1 to 4, wherein the composite layer comprises a portion of the first polymeric macromolecular species or polymer and a portion of the second polymeric macromolecular species or polymer.

6. The article of any one of claims 1 to 5, wherein the mechanically engineered topographical features comprise one or more of mechanically engineered embossed features, mechanically engineered relieved features, mechanically engineered recessed features, mechanically engineered imprinted features, and/or mechanically engineered repetitive features.

7. The article of any one of claims 1 to 5, wherein the mechanically engineered topographical features comprise one or more of mechanically engineered imprinted features and/or mechanically engineered imparted patterns.

8. The article of any one of claims 1 to 5, wherein the mechanically engineered topographical features comprise one or more of mechanically engineered imprinted grain patterns.

9. The article of any one of claims 1 to 5, wherein the mechanically engineered topographical features comprise one or more mechanically engineered imprinted fine grain features having a grain depth between 0-100 μm.

10. The article of any one of claims 1 to 5, wherein the mechanically engineered topographical features comprise one or more mechanically engineered imprinted coarse grain features having a grain depth between 100-150 μm.

11. The article of any one of claims 1 to 10, wherein the composite layer comprises a portion of the base layer and a portion of the top layer which are physically and/or chemically entangled, and/or physically and/or chemically crosslinked, and/or chemically and/or physically integrated.

12. The article of any one of claims 4 to 11, wherein the adhesive layer comprises and/or is generated by one or more of an acrylic dispersion, a polyurethane dispersion, a waterborne urethane-acrylic hybrid dispersion (HPDS), a wax, an oil in water emulsion, and/or a poly siloxane.

13. The article of any one of claims 1 to 12, wherein the first polymeric macromolecular species or polymer compnses a protein component.

14. The article of claim 13, wherein the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, com zein, wheat gluten, pectin, chitin, casein, and/or whey.

15. The article of any one of claims 1 to 13, wherein the base layer comprises and/or is generated by one or more of a polyurethane dispersion, a wax, an oil in water emulsion, and/or a protein binder.

16. The article of any one of claims 1 to 13, wherein the first polymeric macromolecular species or polymer comprises a poly lactic acid (PLA) component, and/or a poly(lactic-co-gly colic acid) (PLGA) component.

17. The article of any one of claims 1 to 16, wherein the first polymeric macromolecular species or polymer comprises a biodegradable polymer.

18. The article of any one of claims 1 to 17, wherein the base layer has a thickness between about 10 pm and about 35 pm.

19. The article of any one of claims 1 to 18, wherein the second polymeric macromolecular species or polymer comprises one or more of a cellulose derivative, an aliphatic or aromatic polyurethane, a silanol/ amino-poly siloxane emulsions, a crosslinked PU, treated silicas, and/or a protein component.

20. The article of claim 19. wherein the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, com zein, wheat gluten, pectin, chitin, casein, and/or whey.

21. The article of any one of claims 1 to 20, wherein the second polymeric macromolecular species or polymer comprises a biodegradable polymer.

22. The article of any one of claims 1 to 21, wherein the second polymeric macromolecular species or polymer comprises a cellulose and/or cellulose derivative component.

23. The article of claim 22, wherein the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose.

24. The article of claim 23, wherein the cellulose derivative is ethyl cellulose.

25. The article of claim 23 or 24. wherein the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%, or from 48.0% to 49.5%.

26. The article of claim 24 or 25, wherein the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5. 1.5 to 2, 2 to 2.5, or 2.5 to 3.

27. The article of any one of claims 24 to 26, wherein a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%, of between about 5% and less than about 100%, of between about 10% and about 20%, between about 20% and about 30%. between about 30% and about 40%. between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%, between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%.

28. The article of any one of claims 24 to 26, wherein a second structure of the cellulose derivative comprises a degree of crystallinity of less than about 99%. less than about 98%, less than about 97%, less than about 96%, less than about 95%, less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%. less than about 84%. less than about 83%. less than about 82%, less than about 81%, less than about 80%, less than about 79%, less than about 78%, less than about 77%, less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%. less than about 71%. less than about 70%. less than about 69%, less than about 68%, less than about 67%, less than about 66%, less than about 65%, less than about 64%, less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%, less than about 45%, less than about 44%, less than about 43%, less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%. less than about 32%. less than about 31%. less than about 30% less than about 29%, less than about 28%, less than about 27%, less than about 26%, less than about 25%, less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%. or less than about 10%.

29. The article of any one of claims 1 to 28, wherein the top layer has a thickness between about 5 μm and about 10 μm.

30. The article of any one of claims 1 to 29, wherein the thickness ratio between the base layer and the top layer ranges from about 10: 1 to about 1:1.

31. The article of any one of claims 1 to 30, wherein the top layer does not include an adhesive material or cross-linker.

32. The article of any one of claims 1 to 31, wherein the first polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite layer.

33. The article of any one of claims 1 to 31, wherein the second polymeric macromolecular species or polymer is distributed anisotropically over a cross section of the composite layer.

34. The article of any one of claims 1 to 33, wherein the substrate comprises an irregular surface.

35. The article of any one of claims 1 to 33, wherein the substrate comprises topographical features which are not mechanically engineered.

36. The article of any one of claims 1 to 35, wherein the coating has a thickness between about 10 μm and about 1000 μm.

37. The article of any one of claims 1 to 36, wherein the amount of coating on the substrate is between about 0.01 g/ft² and about 25 g/ft².

38. The article of any one of claims 1 to 37, wherein the substrate comprises a substantially flexible material.

39. The article of any one of claims 1 to 38, wherein the substrate comprises a leather material or a textile material.

40. The article of any one of claims 1 to 39, wherein the substrate comprises one or more of collagen, fibroin, keratin, cellulose, and/or lignin.

41. The article of any one of claims 1 to 40, wherein the coating comprises one or more mattifying agent.

42. The article of any one of claims 1 to 40, wherein the coating comprises one or more plasticizer.

43. The article of any one of claims 1 to 42, wherein the coating comprises a plurality of modified fibroin fragments, each comprising one or more amino acid residue modifications selected from an asparagine to aspartic acid modification, a glutamine to glutamic acid modification, and a methionine to methionine oxide modification.

44. The article of claim 43, wherein a plurality of modified fibroin fragments comprises one modification.

45. The article of claim 43, wherein a plurality of modified fibroin fragments comprises two modifications.

46. The article of claim 43, wherein a plurality of modified fibroin fragments comprises three modifications.

47. The article of any one of claims 43 to 46, wherein an asparagine to aspartic acid modification is at one or more positions selected from N23. N28, N 108, N 118, N 136, N 186, N200, N204, N240, N248, N68, N70, N77, N5262, N93, N132, N149, N172, N174, N202, N105, N4191,

48. The article of any one of claims 43 to 46, wherein a glutamine to glutamic acid modification is at one or more positions selected from Q24, Q149, Q202. Q58, Q139, Q275, Q5216. Q255, and Q 125,

49. The article of any one of claims 43 to 46, wherein a methionine to methionine oxide modification is at the M64 position.

50. The article of any one of claims 43 to 49, wherein each modification is independently ranging in the composition between about 1% to about 99%.

51. The article of any one of claims 43 to 50, wherein a % modification is defined as (number of modified fibroin fragments having a modification at a specific position divided by the total number of modified fibroin fragments which include the specific position, modified or unmodified) x 100.

52. A method of coating a substrate with a composite coat, the method comprising applying to the substrate a base layer coating composition through a release paper method, wherein the release paper forms a plurality of mechanically engineered topographical features on the base layer opposite to a surface applied to the substrate, wherein the engineered topographical features have width and/or depth dimensions on a scale of from about 0 pm to about 250 μm, and applying atop layer coating composition.

53. The method of claim 52, further comprising applying to the substrate one or more additional layers coating compositions prior to applying the base layer coating composition, the additional layers selected from a preground layer, a ground layer, and an adhesive layer.

54. The method of claim 52 or 53, wherein an adhesive layer coating composition comprises one or more of an acrylic dispersion, a polyurethane dispersion, a waterborne urethane-acrylic hybrid dispersion (HPDS), a wax, an oil in water emulsion, and/or a polysiloxane

55. The method of any one of claims 52 to 54, wherein a base layer coating composition comprises a protein component.

56. The method of claim 55, wherein the protein component comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, com zein, wheat gluten, pectin, chitin, casein, and/or whey.

57. The method of any one of claims 52 to 56, wherein a base layer coating composition comprises one or more of a polyurethane dispersion, a wax, an oil in water emulsion, and/or a protein binder.

58. The method of any one of claims 52 to 56, wherein a base layer coating composition comprises a poly lactic acid (PLA) component, and/or a poly(lactic-co-glycolic acid) (PLGA) component.

59. The method of any one of claims 52 to 56. wherein a base layer coating composition comprises a biodegradable polymer.

60. The method of any one of claims 52 to 59, wherein a top layer coating composition comprises one or more of a cellulose derivative, an aliphatic or aromatic polyurethane, a silanol/amino-polysiloxane emulsions, a crosslinked PU, treated silicas, and/or a protein component.

61. The method of claim 60, wherein a top layer coating composition comprises one or more of silk fibroin proteins or fragments, collagen, elastin, gelatin, com zein, wheat gluten, pectin, chitin, casein, and/or whey.

62. The method of any one of claims 52 to 61, wherein a top layer coating composition a biodegradable polymer.

63. The method of any one of claims 52 to 61, wherein a top layer coating composition comprises a cellulose and/or cellulose derivative component.

64. The method of claim 63, wherein the cellulose derivative is selected from methyl cellulose, ethyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, cellulose triacetate, cellulose propionate, cellulose nitrate, cellulose sulfate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and microcrystalline cellulose.

65. The method of claim 63, wherein the cellulose derivative is ethyl cellulose.

66. The method of claim 64 or 65. wherein the ethoxyl content in ethyl cellulose is from 45.0% to 49.5%, from 45.0% to 46.0%, from 45.0% to 47.0%, from 47.0% to 48.0%. or from 48.0% to 49.5%.

67. The method of claim 65 or 66, wherein the degree of substitution of the ethyl cellulose is 0.5 to 1, 1 to 1.5. 1.5 to 2, 2 to 2.5, or 2.5 to 3.

68. The method of any one of claims 65 to 67. wherein a second structure of the cellulose derivative comprises a degree of crystallinity of less than 100%, of between about 5% and less than about 100%, of between about 10% and about 20%, between about 20% and about 30%. between about 30% and about 40%, between about 40% and about 50%, between about 50% and about 60%, between about 60% and about 70%. between about 70% and about 80%, between about 80% and about 90%, between about 90% and about 99%, or between about 90% and about 100%.

69. The method of any one of claims 65 to 67, wherein a second structure of the cellulose derivative comprises a degree of crystallinity’ of less than about 99%, less than about 98%. less than about 97%. less than about 96%. less than about 95%. less than about 94%, less than about 93%, less than about 92%, less than about 91%, less than about 90%, less than about 89%, less than about 88%, less than about 87%, less than about 86%, less than about 85%. less than about 84%. less than about 83%. less than about 82%. less than about 81%. less than about 80%. less than about 79%. less than about 78%. less than about 77%. less than about 76%, less than about 75%, less than about 74%, less than about 73%, less than about 72%. less than about 71%. less than about 70%. less than about 69%. less than about 68%. less than about 67%. less than about 66%. less than about 65%. less than about 64%. less than about 63%, less than about 62%, less than about 61%, less than about 60%, less than about 59%, less than about 58%, less than about 57%, less than about 56%, less than about 55%, less than about 54%, less than about 53%, less than about 52%, less than about 51%, less than about 50% less than about 49%, less than about 48%, less than about 47%, less than about 46%. less than about 45%. less than about 44%. less than about 43%. less than about 42%, less than about 41%, less than about 40%, less than about 39%, less than about 38%, less than about 37%, less than about 36%, less than about 35%, less than about 34%, less than about 33%. less than about 32%. less than about 31%. less than about 30% less than about 29%. less than about 28%. less than about 27%. less than about 26%. less than about 25%. less than about 24%, less than about 23%, less than about 22%, less than about 21%, less than about 20% less than about 19%, less than about 18%, less than about 17%, less than about 16%, less than about 15%, less than about 14%, less than about 13%, less than about 12%, less than about 11%, or less than about 10%.

70. The method of any one of claims 52 to 69. wherein the substrate comprises a substantially flexible material.

71. The method of any one of claims 52 to 69, wherein the substrate comprises a leather material or a textile material.

72. The method of any one of claims 52 to 69. wherein the substrate comprises one or more of collagen, fibroin, keratin, cellulose, and/or lignin.

73. The method of any one of claims 52 to 72, wherein a coating composition comprises a mattifying agent.

74. The method of any one of claims 52 to 72. wherein a coating composition comprises a plasticizer.

75. The method of any one of claims 52 to 74, wherein a coating composition comprises a plurality of modified fibroin fragments, each comprising one or more amino acid residue modifications selected from an asparagine to aspartic acid modification, a glutamine to glutamic acid modification, and a methionine to methionine oxide modification.

76. The method of claim 75, wherein a plurality of modified fibroin fragments comprises one modification.

77. The method of claim 75, wherein a plurality of modified fibroin fragments comprises two modifications.

78. The method of claim 75, wherein a plurality of modified fibroin fragments comprises three modifications.

79. The method of any one of claims 75 to 78, wherein an asparagine to aspartic acid modification is at one or more positions selected from N23, N28, N108, N118, N136, N186, N200, N204, N240, N248, N68, N70, N77, N5262, N93, N132, N149, N172, N174, N202, N105, N4191.

80. The method of any one of claims 75 to 78. wherein a glutamine to glutamic acid modification is at one or more positions selected from Q24, Q149, Q202, Q58, Q139, Q275, Q5216, Q255, and Q125.

81. The method of any one of claims 75 to 78, wherein a methionine to methionine oxide modification is at the M64 position.

82. The method of any one of claims 75 to 81, wherein each modification is independently ranging in the composition between about 1% to about 99%.

83. The method of any one of claims 75 to 82, wherein a % modification is defined as (number of modified fibroin fragments having a modification at a specific position divided by the total number of modified fibroin fragments which include the specific position, modified or unmodified) x 100.

84. The method of any one of claims 52 to 83, wherein a coating composition further comprises a solvent component.

85. The method of claim 84, wherein the solvent component comprises an alcohol and/or an alcohol derivative.

86. The method of claim 84 or 85, wherein the solvent component comprises one or more of an alcohol, an ether, a ketone, an aldehyde, and/or a ketal.

87. The method of any one of claims 84 to 86. wherein the solvent component is from about 75% w/w to about 99% w/w of the coating composition, from about 80% w/w to about 98% w/w of the coating composition, from about 85% w/w to about 97.5% w/w of the coating composition, or from about 85% w/w to about 95% w/w of the coating composition.

88. The method of any one of claims 84 to 87, wherein the solvent component comprises one or more of methanol, ethanol, n-propanol, 2-propanol. n-butanol, 2-butanoL pentanol, hexanol, acetone, butanone, methoxypropanol, di-isopropylidene glycerol, 2,2- dimethyl-4-hydroxymethyl- 1,3 -dioxolane, 2,2-dimethyl-1,3-dioxolane-4-methanol, or any combination thereof.

89. The method of any one of claims 52 to 88, wherein a coating composition comprises one or more of a polyethylene glycol (PEG) component, a polypropylene glycol (PPG) component, and/or a polyether component.

90. The method of any one of claims 52 to 88, wherein a coating composition comprises one or more of fatty acid or fatty acid derived amide, and/or a monoglyceride, diglyceride, and/or triglyceride.

91. The method of any one of claims 52 to 88. wherein a coating composition comprises one or more of a triethylene glycol monomethyl ether component, a diethylene glycol butyl ether component, a diethylene glycol ethyl ether component, a dimethyl tetradecanedi oate component, an erucamide component, and/or a glyceryl stearate component.

92. The method of any one of claims 52 to 91, wherein a coating composition comprises water.

93. The method of any one of claims 52 to 92, wherein a coating composition comprises a mattifying agent.

94. The method of any one of claims 52 to 92. wherein a coating composition comprises a plasticizer.

95. The method of any one of claims 52 to 94, further comprising one or more pressing steps, and/or one or more drying or partial drying steps.

96. The method of any one of claims 52 to 95. wherein a first coating composition is partially polymerized, partially dried, and/or partially cured before a second coating composition is applied.

97. The method of any one of claims 52 to 96, wherein a coating composition is applied at a rate from about 0.5 mL/ft² to about 5 mL/ft².

98. An article comprising a substrate and a coating, the article made by a method of any one of claims 52 to 97.