CN114716724B - Bionic intelligent hydrogel based on cuttlefish bone and preparation method thereof - Google Patents

Abstract

The invention discloses a bionic intelligent hydrogel based on cuttlefish bones and a preparation method thereof. According to the method, cuttlefish bones are used as raw materials, and through the steps of deproteinization, decalcification and the like, a chitin semitransparent film with a layered structure is obtained, and then the chitin semitransparent film and a temperature-sensitive polymer are used for constructing the intelligent hydrogel with a gradient structure. The hydrogel prepared by the invention has good temperature sensitivity, and can be reversibly bent and changed in transparency under the influence of temperature. The preparation method of the invention has simple operation and lower cost. The prepared hydrogel has multiple response characteristics and has a good application prospect in the field of intelligent driving. Not only provides a new way for the intelligent utilization of ocean wastes such as cuttlefish bones, but also provides a new idea for constructing novel bionic intelligent hydrogel.

Description

A biomimetic intelligent hydrogel based on cuttlebone and its preparation method

technical field

The invention relates to a bionic intelligent hydrogel based on cuttlebone and a preparation method thereof. The cuttlebone with a layered structure is used as a raw material, and a translucent chitin film with a layered structure is left after removing protein and calcium carbonate. Composite with temperature-sensitive polymers to build a heat-stimuli dual-response smart hydrogel with a gradient structure, which belongs to the field of smart polymer materials.

Background technique

Smart material is a new type of functional material that rapidly responds to changes in the surrounding environment by autonomously changing its structure, properties, and functions. It is the fourth generation of materials after natural materials, synthetic polymer materials, and artificially designed materials. Smart hydrogels are one of them. Based on the three-dimensional network structure and environmental sensitivity of hydrogels, smart hydrogels have been applied in memory materials, soft robots, biosensors, drug delivery and other fields. widespread attention.

Cuttlefish is the fastest swimming invertebrate in the ocean. Cuttlefish bone is a natural porous layered material with the advantages of light weight and high strength. Its main components are calcium carbonate, chitin and protein. At present, there are not many studies on cuttlebone, and most of them focus on the research and analysis of the mechanical properties of the internal microstructure of cuttlebone. With the gradual emphasis on the development and utilization of renewable resources, it is necessary to carry out subsequent research, development and application of cuttlebone.

Building poly(N-isopropylacrylamide) (PNIPAM) hydrogels with gradient distributions of polymer chains, crosslink densities, fillers, or pores in monolayer poly-N-isopropylacrylamide (PNIPAM) hydrogels is a way to construct smart temperature-responsive hydrogels. Bao-Yi Wu et al. used the mask method to prepare PNIPAM hydrogels with gradient structure by using the limited penetration ability of light in the material to realize the shape response under temperature stimulation (Wu B-Y, Le X-X, Jian Y-K, Lu W, Yang Z-Y, Zheng Z-K, et al. pH and thermodual-responsive fluorescent hydrogel actuator. Macromol Rapid Commun 2019; 40:1800648.); Taka-aki Asoh et al. Constructed PNIPAM with a gradient structure by using added filling substances to move in a specific electric field Hydrogels (Asoh T-a, Matsusaki M, Kaneko T, Akashi M.Fabrication of temperature-responsive bending hydrogels with a nanostructured gradient. AdvMater2008; 20:2080–3.); Yang Liu et al. use the added filling material to move in a specific magnetic field Construction of PNIPAM hydrogels with gradient structures (Liu Y, Takafuji M, Ihara H, Zhu M, Yang M, Gu K, et al. Programmable responsive shaping behavior induced by visible multi-dimensional gradients of magnetic nanoparticles. Soft Matter 2012; 8 :3295–9.); Rongcong Luo et al. used precipitation to construct PNIPAM hydrogels with gradient structures (Luo R, Wu J, Dinh N-D, Chen C-H. Gradient porous elastic hydrogels with shape-memory property and anisotropic responses for programmable locomotion. Adv Funct Mater 2015;25:7272–9.). However, few people have explored the use of the layered structure of biomass itself to construct smart-driven hydrogels.

Contents of the invention

In order to explore a new method for constructing intelligently driven hydrogels, the present invention creatively utilizes the characteristics of the difference in strength and swelling degree between chitin films and temperature-sensitive polymers, and uses cuttlefish bone and temperature-sensitive polymers as raw materials to prepare A new type of intelligent actuation hydrogel. The hydrogel undergoes a reversible shape bending change under the influence of temperature in water. In addition, since the temperature-sensitive polymer runs through the entire hydrogel network system, the transparency of the hydrogel will also change with the change of temperature. The preparation method of the invention has simple operation and low cost. The prepared hydrogel has multiple response characteristics and has a good application prospect in the field of intelligent driving.

The technical scheme adopted in the present invention is as follows:

A method for preparing a biomimetic intelligent hydrogel based on cuttlebone, comprising the following steps:

(1) Cuttlefish bone slices: Cut the cuttlefish bone into a shape of 2-10cm in length, 1-5cm in width, and 0.2-2cm in thickness;

(2) Pretreatment of cuttlebone: remove the protein and calcium carbonate in cuttlebone to obtain a layered translucent chitin film with a thickness of 2-20mm, then wash it with deionized water and ethanol solution until neutral, and remove it by vacuuming Air bubbles in the film, then place it in an oven at 45-55°C for 1-5 hours to dry to form a semi-dry film with a thickness of 0.2-2mm.

(3) Preparation of hydrogel prepolymer: Mix the temperature-sensitive polymer monomer, water, pore forming agent, crosslinking agent, and photoinitiator uniformly under dark conditions to obtain a uniform and transparent prepolymer solution. The mass ratio of the monomer, water, pore forming agent, crosslinking agent and photoinitiator of the temperature-sensitive polymer is (25～400):(15～2400):(20～400):(1～15 ): (1.2～20). Put the semi-dry film obtained in step (2) into the prepolymer solution to avoid light and vacuumize for 10-40 minutes, and pass nitrogen gas for 5-20 minutes.

(4) Take out the film, place it in the silica gel model between the two press plates, pour the prepolymer solution into the template, seal it with a clip, put it in an ice-water bath, and irradiate it with ultraviolet light for 10-30 minutes to obtain the cuttlefish-based Bone-inspired smart hydrogels.

Further, in the preparation method provided by the present invention, the cuttlebone in step (1) is marine waste cuttlebone.

Further, in the preparation method provided by the present invention, the semi-dry film in step (2) is a chitin translucent film with a layered structure.

Further, in the preparation method provided by the present invention, the specific method for removing the protein and calcium carbonate in the cuttlebone described in step (2) is: boil the cuttlefish bone with a sodium hydroxide solution with a mass volume ratio of 1% to 5% for 1 to 10 minutes. The protein in the cuttlebone was removed for 3 hours, then washed with deionized water until neutral, then soaked in 3% to 7% hydrochloric acid solution by mass ratio for 12 to 30 hours to remove calcium carbonate, and then washed with deionized water and ethanol until neutral.

Further, in the preparation method provided by the present invention, in step (3), the chitin semi-dry film is immersed in the prepolymer solution, and treated by vacuum filtration for 10-40 minutes.

Further, in the preparation method provided by the present invention, the temperature-sensitive polymer described in step (3) includes poly-N-isopropylacrylamide (PNIPAM) and poly-N-acryloyl glycinamide (PNAGA) and other temperature-sensitive polymers. more than one of the species.

Furthermore, in the preparation method provided by the present invention, the pore-forming agent in step (3) is at least one of polyethylene glycol, silica gel particles and other substances. The hydrogel with porous structure can accelerate the volume change.

Furthermore, in the preparation method provided by the present invention, the crosslinking agent in step (3) is at least one of N,N'-methylenebisacrylamide, polyethylene glycol diacrylate and the like.

Further, in the preparation method provided by the present invention, the photoinitiator described in step (3) is one of 2-hydroxy-2-methylpropiophenone, trimethylbenzoyl-diphenylphosphine oxide (TPO), etc. above.

Further, in the preparation method provided by the present invention, the biomimetic smart hydrogel in step (4) is to construct a temperature-sensitive hydrogel with a gradient structure by adding a layered substance with chitin on one side.

Furthermore, in the preparation method provided by the present invention, the biomimetic smart hydrogel system in step (4) is an interpenetrating network hydrogel structure composed of chitin and thermosensitive polymers.

The present invention also provides a cuttlebone-based biomimetic intelligent hydrogel prepared by the above preparation method.

Furthermore, when the prepared hydrogel is placed in water at different temperatures, the transparency of the hydrogel will change.

Furthermore, when the prepared hydrogel is placed in water at different temperatures, the shape of the hydrogel will change reversibly.

In the present invention, the cuttlefish bone is deproteinized, calcium carbonate removed, washed with deionized water, and dried to obtain a translucent chitin film. It is observed through an electron microscope that its layered structure is preserved, and its strength reaches 42 MPa. Inspired by the "smart" behavior of biological temperature, the chitin film is filled on one side of the temperature-sensitive polymer hydrogel. Due to the difference in strength and swelling between the two, it can cause reversible shape changes, and at the same time Realize transition between transparent and opaque in smart hydrogels.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) In the present invention, the structure of chitin thin film is non-uniformly doped in the temperature-sensitive polymer hydrogel, so that the shape of the hydrogel changes accordingly when the temperature changes.

(2) The present invention uses temperature-sensitive polymer hydrogel as a raw material, which not only swells and shrinks due to temperature changes, but also changes its transparency with temperature changes.

(3) The hydrogel prepared by the present invention has the property that its transparency changes with the temperature change, and has the property that its shape changes with the temperature change, which can realize the multi-responsive function of the material. The preparation method of the invention has simple operation and low cost.

(4) The raw material used in the present invention is cuttlebone, which belongs to a kind of marine waste. The present invention cleverly utilizes its structure and composition to produce smart materials, which improves its use value and provides a new way of thinking.

Description of drawings

Fig. 1 is the schematic diagram of the preparation of the biomimetic intelligent hydrogel based on cuttlebone in Example 1 of the present invention;

Fig. 2 is the electron micrograph after removing protein and calcium carbonate in embodiment 1 cuttlefish bone;

Fig. 3 is the FT-IR figure of embodiment 1 cuttlefish bone and cuttlefish bone after removing protein and calcium carbonate;

Fig. 4 is the transparency figure of embodiment 1 biomimetic intelligent hydrogel under low temperature and high temperature situation;

Fig. 5 is a graph of the shape change with time of the biomimetic smart hydrogel of Example 1 in water at 40°C and 20°C.

Detailed ways

The technical solution of the present invention will be clearly and completely described below in conjunction with the technical process steps in the specific embodiments of the present invention, specific implementation conditions and materials, and the accompanying drawings. Apparently, the described embodiments are only some of the embodiments of the present invention and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Cut the cuttlefish bone into cuboids with a length of 4cm, a width of 1cm, and a thickness of 1.5cm. The sliced cuttlefish bones were soaked in 1% sodium hydroxide solution with a mass volume ratio and boiled for 1 h, then washed with deionized water until neutral, and then dried in an oven. Immerse the dried cuttlefish bone in a 3% hydrochloric acid solution by mass ratio for 12 hours, wash it with deionized water and ethanol successively to neutrality, remove the air bubbles in the sample by vacuuming, and then place it in an oven at 55°C for 1 hour until it is semi-dry film with a thickness of 1.5 mm.

Then a part of the sample was taken out and freeze-dried to observe its structure with a field emission scanning electron microscope. As shown in Figure 2, it was found that the cuttlebone after removing protein and calcium carbonate still retained a layered structure. Then carry out infrared analysis to the sample, the result is shown in Figure 3, the comparison spectrum shows that the remaining main component of cuttlebone after removing calcium carbonate and protein is chitin.

Weigh 3g of N-isopropylacrylamide, 3g of polyethylene glycol, 0.03g of N,N'-methylenebisacrylamide, 12uL of 2-hydroxy-2-methylpropiophenone, 24mL of water, mix and stir 5min to form a uniform and transparent PNIPAM prepolymer solution. Put the semi-dry film into the prepolymer solution to avoid light and vacuumize for 10 minutes, and pass nitrogen gas for 5 minutes. Take out the film and place it in a silica gel model sandwiched between two glass plates, then pour the PNIPAM prepolymer solution into the template and seal it with a clip. Put it into an ice-water bath, irradiate with ultraviolet light for 10 minutes to form a hydrogel, and obtain the biomimetic intelligent hydrogel based on cuttlebone.

The transparency of the prepared hydrogel is different when placed at 40°C and at 20°C, as shown in Figure 4, the transparency of the hydrogel reaches more than 80% at 20°C, and the hydrogel turns white at 40°C opaque. In addition, the hydrogel was placed in hot water at 40°C for 55 minutes, and its shape change was observed every 5 minutes. As shown in Figure 5, the shape of the hydrogel also gradually became curved, bending to the side not filled with chitin film . Subsequently, the curved hydrogel was placed in cold water at 20°C for 55 minutes, and its shape change was observed every 5 minutes. The shape of the hydrogel also slowly returned to its original shape from the side that was not filled with the chitin film. It shows that the prepared hydrogel has good temperature-sensitive properties, and under the influence of temperature, reversible bending and transparency changes will occur. The schematic diagram of the shape change of hydrogel is shown in Figure 1. The change of N-isopropylacrylamide based on temperature will lead to the change of volume. When the temperature rises and is higher than 32 °C, N-isopropylacrylamide The gel will shrink, but because one side of the hydrogel contains a chitin layered membrane, its volume will not change with temperature, and the asymmetric volume change of the overall hydrogel will cause the hydrogel to bend. When the temperature is lowered below 32 °C, the N-isopropylacrylamide hydrogel will swell and restore the overall hydrogel to its original shape.

Example 2

Cut the cuttlefish bone into cuboids with a length of 10cm, a width of 5cm and a thickness of 2cm. The sliced cuttlefish bones were soaked in a 3% sodium hydroxide solution and boiled for 2 hours, then washed with deionized water until neutral, and then dried in an oven. Immerse the dried cuttlefish bone in a 5% hydrochloric acid solution by mass ratio for 24 hours, wash it with deionized water and ethanol successively until neutral, remove air bubbles by vacuuming, and then place it in an oven at 50°C for 3 hours to form a semi-dry film , and its thickness is 2mm.

Weigh 5g of N-isopropylacrylamide, 4g of polyethylene glycol, 0.05g of N,N'-methylenebisacrylamide, 25uL of 2-hydroxy-2-methylpropiophenone, 30mL of water, mix and stir 5min to form a uniform and transparent PNIPAM prepolymer solution. Put the semi-dry film into the prepolymer solution to avoid light and vacuumize for 20 minutes, and pass nitrogen gas for 10 minutes. Take out the film and place it in a silica gel model sandwiched between two glass plates, then pour the PNIPAM prepolymer solution into the template and seal it with a clip. Put it into an ice-water bath, irradiate with ultraviolet light for 20 minutes to form a hydrogel, and obtain the biomimetic intelligent hydrogel based on cuttlebone.

The prepared hydrogel was placed in hot water at 40°C, and it was observed that its transparency changed from transparent to opaque, and its color changed from colorless to white. After standing for 20min, the hydrogel becomes bent and bends to the side not filled with the chitin film. The hydrogel was placed in cold water at 4°C. After 1 minute, the gel became transparent again, the color changed from white to colorless, and the shape of the hydrogel slowly returned to its original shape.

Example 3

Cut the cuttlefish bone into cuboids with a length of 8cm, a width of 2cm and a thickness of 1cm. The sliced cuttlefish bones were soaked in a 5% sodium hydroxide solution and boiled for 2.5 hours, then washed with deionized water until neutral, and then dried in an oven. Immerse the dried cuttlefish bone in a 6% hydrochloric acid solution by mass ratio for 26 hours, wash it with deionized water and ethanol successively until neutral, use vacuum to remove air bubbles, and then place it in an oven at 50°C for 4 hours to form a semi-dry film , and its thickness is 0.2mm.

Weigh 9g of N-isopropylacrylamide, 9g of silica gel particles, 0.1g of polyethylene glycol diacrylate, measure 40uL of trimethylbenzoyl-diphenylphosphine oxide, and 50mL of water, mix and stir for 5min to form a uniform Transparent PNIPAM prepolymer solution. Put the semi-dry film into the prepolymer solution to avoid light and vacuumize for 30 minutes, and pass nitrogen gas for 15 minutes. Take out the film and place it in a silica gel model sandwiched between two glass plates, then pour the PNIPAM prepolymer solution into the template and seal it with a clamp. Put it into an ice-water bath, irradiate with ultraviolet light for 30 minutes to form a hydrogel, and obtain the biomimetic intelligent hydrogel based on cuttlebone.

The prepared hydrogel was placed in hot water at 60°C, and it was observed that its transparency changed from transparent to opaque, and its color changed from colorless to white. After standing for 10 minutes, the hydrogel becomes bent and bends to the side not filled with the chitin film. The hydrogel was placed in cold water at 4°C. After 1 min, the gel became transparent again, and the color changed from white to colorless. The shape of the hydrogel also slowly returned to its original shape from the side not filled with the chitin film.

Example 4

Cut the cuttlefish bone into cuboids with a length of 2cm, a width of 1cm, and a thickness of 0.2cm. The sliced cuttlefish bones were soaked in a 4% sodium hydroxide solution and boiled for 3 hours, then washed with deionized water until neutral, and then dried in an oven. Immerse the dried cuttlefish bone in a 7% hydrochloric acid solution by mass for 30 hours, wash it with deionized water and ethanol successively until neutral, remove air bubbles by vacuuming, and then place it in an oven at 45°C for 5 hours to form a semi-dry film , and its thickness is 0.2mm.

Weigh 9g of N-acryloyl glycinamide, 10g of polyethylene glycol, 0.1g of polyethylene glycol diacrylate, measure 40uL of trimethylbenzoyl-diphenylphosphine oxide, 50mL of water, mix and stir for 5min, A uniform and transparent PNAGA prepolymer solution was formed. Put the semi-dry film into the prepolymer solution to avoid light and vacuumize for 40 minutes, and pass nitrogen gas for 20 minutes. Take out the film and place it in a silica gel model sandwiched between two glass plates, then pour the PNAGA prepolymer solution into the template and seal it with a clip. Put it into an ice-water bath, irradiate with ultraviolet light for 30 minutes to form a hydrogel, and obtain the biomimetic intelligent hydrogel based on cuttlebone.

The prepared hydrogel was placed in hot water at 60°C, and its transparency was observed to change from opaque to transparent. After standing for 10 minutes, the hydrogel becomes bent and bends to the side filled with the chitin film. The hydrogel was placed in cold water at 4°C, and the color of the gel also changed from transparent to opaque after 1 min. The shape of the hydrogel also slowly returned to its original shape from the side filled with the chitin film.

Notes to all technical personnel: Although the present invention has been described according to the above-mentioned specific embodiments, the inventive concept of the present invention is not limited to this invention, and any modification using the inventive concept will be included in the protection scope of the patent claims.

Claims (7)

1. The preparation method of the bionic intelligent hydrogel based on the cuttlefish bone is characterized by comprising the following steps of:

(1) Cuttlefish bone slice: cutting cuttlefish bones into a shape with the length of 2-10 cm, the width of 1-5 cm and the thickness of 0.2-2 cm;

(2) Pretreatment of cuttlefish bone: removing protein and calcium carbonate in the cuttlefish bone to obtain a layered semitransparent chitin film with the thickness of 2-20 mm, washing the layered semitransparent chitin film to be neutral by deionized water and ethanol solution, removing bubbles in the film by using a vacuumizing mode, and then placing the film in a 45-55 ℃ C oven for 1-5 hours to bake the film to form a half dry film;

(3) Preparing hydrogel polymer: uniformly mixing a monomer of a temperature-sensitive polymer, water, a pore-forming agent, a crosslinking agent and a photoinitiator under a light-shielding condition to obtain a uniform and transparent prepolymer solution, then placing the semi-dried film obtained in the step (2) into the prepolymer solution, performing vacuum filtration for 10-40 min under the light shielding condition, and introducing nitrogen for 5-20 min;

(4) Taking out the film, placing the film in a silica gel model between two pressing plates, pouring the prepolymer solution into a template, sealing the template by using a clamp, and placing the template in an ice water bath, and irradiating ultraviolet light for 10-30 min to obtain the bionic intelligent hydrogel based on the cuttlefish bone; the bionic intelligent hydrogel is a temperature-sensitive hydrogel with a gradient structure constructed by a method of adding a chitin lamellar substance on one side;

the temperature-sensitive polymer in the step (3) is more than one of poly N-isopropyl acrylamide and poly N-acryl glycinamide;

the mass ratio of the monomer, water, pore-forming agent, cross-linking agent and photoinitiator of the temperature-sensitive polymer in the step (3) is (25-400), 15-2400, 20-400, 1-15 and 1.2-20.

2. The method for preparing the bionic intelligent hydrogel based on the cuttlefish bone according to claim 1, wherein the specific method for removing protein and calcium carbonate in the cuttlefish bone in the step (2) is as follows: boiling the cuttlefish bone for 1-3 hours by adopting a sodium hydroxide solution with the mass-volume ratio of 1% -5% to remove protein, washing the cuttlefish bone to be neutral by using deionized water, soaking the cuttlefish bone for 12-30 hours by adopting a hydrochloric acid solution with the mass ratio of 3% -7% to remove calcium carbonate, and washing the cuttlefish bone to be neutral by using deionized water and ethanol.

3. The method for preparing the bionic intelligent hydrogel based on the cuttlefish bone, which is characterized in that the semi-dry film in the step (2) is a chitin semitransparent film with a layered structure.

4. The method for preparing the bionic intelligent hydrogel based on the cuttlefish bone, which is disclosed in claim 1, is characterized in that the pore-forming agent in the step (3) is more than one of polyethylene glycol and silica gel particles.

5. The method for preparing the bionic intelligent hydrogel based on the cuttlefish bone, which is disclosed in claim 1, is characterized in that the cross-linking agent in the step (3) is more than one of N, N' -methylene bisacrylamide and polyethylene glycol diacrylate.

6. The method for preparing the bionic intelligent hydrogel based on the cuttlefish bone, which is characterized in that the photoinitiator in the step (3) is more than one of 2-hydroxy-2-methyl propiophenone and trimethyl benzoyl-diphenyl phosphine oxide.

7. A bionic intelligent hydrogel based on cuttlefish bone prepared by the preparation method of any one of claims 1-6.