CN116806818B

CN116806818B - Supramolecular hybrid hydrogel and preparation method thereof, pesticide and preparation method thereof

Info

Publication number: CN116806818B
Application number: CN202310572192.2A
Authority: CN
Inventors: 张玉辉; 刘晨爽; 王杰; 盛显良; 斯琴塔娜; 田野
Original assignee: Inner Mongolia Agricultural University
Current assignee: Inner Mongolia Agricultural University
Priority date: 2023-05-19
Filing date: 2023-05-19
Publication date: 2025-08-29
Anticipated expiration: 2043-05-19
Also published as: CN116806818A

Abstract

The present invention relates to an environmentally friendly supramolecular hybrid hydrogel with high pesticide release, which is constructed by utilizing the supramolecular complexation of a β-CD cavity and an arylazopyrazole group (AAP) and the electrostatic interaction between a laponite (LP) surface and a positively charged group. Agrochemicals can be loaded on the hydrogel, and the release of the agrochemicals can be controlled. Under continuous ultraviolet irradiation, the cumulative release of the agrochemicals can reach more than 60%. In addition, the supramolecular hybrid hydrogel after releasing the agrochemicals can also adsorb heavy metal ions in the soil, reduce environmental pollution, and be more environmentally friendly.

Description

Supermolecule hybridized hydrogel and preparation method thereof, pesticide and preparation method thereof

Technical Field

The invention relates to the technical field of hydrogels, in particular to a supermolecule hybrid hydrogel, a preparation method thereof, a pesticide and a preparation method thereof.

Background

In recent years, the controlled release technology has the advantages of reducing pesticide loss, reducing pesticide consumption, reducing environmental pollution and the like, and is considered as a promising strategy for improving pesticide utilization efficiency and solving environmental problems. At present, pesticide delivery systems based on mesoporous silica nanoparticles, carbon nanomaterials, polymer micelles and metal/metal oxide nanoparticles have been constructed, and the utilization efficiency of pesticides is improved, but the preparation of these systems still has the problems of poor biodegradability of raw materials, toxicity of organic solvents, insufficient release of pesticides and the like.

Therefore, there is a need to develop an environment-friendly pesticide controlled release system with high pesticide release.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an environment-friendly supermolecule hybrid hydrogel with high pesticide release amount.

It is another object of the present invention to provide a method for preparing the supramolecular hybrid hydrogel.

It is a further object of the present invention to provide a pesticide comprising said supramolecular hybrid hydrogel.

It is a further object of the present invention to provide a process for the preparation of said pesticide.

In order to achieve the above object, the present invention provides the following technical solutions.

In a first aspect, the present invention provides a supramolecular hybrid hydrogel comprising laponite, arylazopyrazole modified hyaluronic acid and a β -cyclodextrin modified with positively charged groups;

the arylazo pyrazole modified hyaluronic acid has the following structural formula:

Wherein R is methyl, hydroxyl or halogen, q is an integer of 0-5, m is 100-110, and n is 690-700;

The beta-cyclodextrin modified with positively charged groups has the following structural formula:

wherein R' is the positively charged group.

The supermolecule hybridized hydrogel is environment-friendly and light-responsive polysaccharide-based supermolecule hybridized hydrogel, can be loaded with agricultural chemicals, can control the release of the agricultural chemicals, and can achieve the accumulated release amount of the agricultural chemicals of more than 60% under the continuous ultraviolet irradiation. In addition, the supermolecule hybridized hydrogel after releasing agricultural chemicals can adsorb heavy metal ions in soil, so that environmental pollution is reduced.

The invention utilizes the supermolecular complexation of beta-cyclodextrin (beta-CD) cavity and aryl azo pyrazole group (AAP) and the electrostatic interaction of hectorite (LP) surface and positively charged group to construct hyaluronic acid group supermolecule hybrid hydrogel. The system HAs some inherent characteristics that (1) nano clay is a very promising drug delivery material, the incorporation of LP and biocompatible polymer Hyaluronic Acid (HA) can form a stable three-dimensional hydrogel network, the stable three-dimensional hydrogel network HAs good mechanical strength and performance, including high drug loading capacity, water solubility and biocompatibility of agricultural chemicals are improved, and the sustained release of the drug is improved, (2) the stimulus response release of the agricultural chemicals is targeted, and host-object pairs of beta-cyclodextrin and AAP are introduced as stimulus response sites, because the host-object pairs have light response to ultraviolet light, so that the supermolecule hybridized hydrogel can be controlled to release through the transformation of light-controlled gel-sol, and (3) after the HA releases the pesticide, rich carboxyl groups of the HA can further form a complex with heavy metal ions. Therefore, the supermolecule hybridized hydrogel provided by the invention can provide a new choice for precise agriculture.

In some embodiments of the invention, m may be 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, or 110. Preferably, m is 100-105.

In some embodiments of the invention, n may be 690, 691, 692, 693, 694, 695, 696, 697, 698, 699, or 700. Preferably, n is 690-695.

In the present invention, q represents the number of substituents R on the phenyl group. Preferably q is an integer from 0 to 2.

In some embodiments of the invention, the positively charged group R' is one of the following structures:

wherein t is an integer of 0 to 2. Preferably, the positively charged group R' is The positive charge on the guanidino group is readily electrostatically bound to the negatively charged hectorite to facilitate the construction of a crosslinked cellular hydrogel structure.

In some embodiments of the invention, the arylazo pyrazole modified hyaluronic acid isThe beta-cyclodextrin modified with positively charged groups is

The "aryl" in the "arylazo pyrazole" is preferably an unsubstituted phenyl group. Due to the limited size of the β -CD cavity, the selection of unsubstituted phenylazopyrazoles is more advantageous for the complexation of this group with the β -CD cavity, thus forming a stable host-guest pair.

In some embodiments of the invention, the mass ratio of the arylazo pyrazole modified hyaluronic acid, the beta-cyclodextrin modified with positively charged groups, and the laponite is (0.05-0.1): 0.01-0.05): 1.

The mass ratio of the three substances is controlled, which is beneficial to constructing the supermolecule hybridized hydrogel with a three-dimensional network structure.

In some embodiments, the mass ratio of the arylazo pyrazole modified hyaluronic acid, the β -cyclodextrin modified with positively charged groups, and the laponite may be 0.05:0.01:1, 0.06:0.02:1, 0.07:0.03:1, 0.08:0.04:1, 0.09:0.05:1, 0.1:0.05:1.

In some embodiments of the invention, R may be methyl. q may be an integer from 0 to 2. m may be 103 and n may be 694.

In a second aspect, the present invention provides a method for preparing the supramolecular hybrid hydrogel, see fig. 1, comprising the steps of:

Hyaluronic acid in the presence of a base Carboxyl activating agentReacting to obtain aryl azo pyrazole modified hyaluronic acid, wherein R is methyl, hydroxyl or halogen, q is an integer of 0-5, m is 100-110, and n is 690-700;

Dissolving the arylazo pyrazole modified hyaluronic acid and the beta-cyclodextrin modified with positively charged groups in a solvent to obtain clathrate solution, and

And mixing hectorite, a stripping agent and the inclusion compound solution, and stirring until the mixture loses fluidity, thus obtaining the supermolecule hybrid hydrogel.

The preparation method provided by the invention has the advantages of simple process and strong repeatability, and is suitable for large-scale industrial production.

In some embodiments of the invention, the base may be one or more of triethylamine, 4-dimethylaminopyridine, 1-hydroxybenzotriazole. Facilitating carboxyl groups in hyaluronic acid in the presence of a baseAmino groups in (a) are reacted.

In some embodiments of the invention, the carboxyl activating agent may be one or more of ethyl chloroformate, isobutyl chloroformate, N-hydroxysuccinimide. The carboxyl activator is used for activating carboxyl in hyaluronic acid, so that the reactivity of the carboxyl can be obviously improved, and the hyaluronic acid can be more quickly matched with the carboxylThe amino group in the (B) is reacted, the reaction rate is improved, the reaction time is shortened, and the time cost is saved.

In some embodiments of the invention, the release agent may be sodium polyacrylate. The hectorite is a layered material, and the stripping agent is added to strip the hectorite into nano-sheets with negative charges, so that electrostatic interaction between the positive charge groups and the hectorite is improved, and the structure of the supermolecule hybrid hydrogel is stabilized.

In some embodiments of the invention, the solvent used to prepare the clathrate solution may be one or more of water, dimethyl sulfoxide.

In some embodiments of the present invention, the arylazo pyrazole modified hyaluronic acid is prepared by adding the hyaluronic acid to a solvent, heating to dissolve, cooling to 20-30deg.C, adding the base, stirring, adding the carboxyl activator, continuing stirring, and addingAfter the reaction is completed, water is added for dilution, and freeze-drying is performed after dialysis.

Preferably, the solvent used for dissolving the hyaluronic acid is one or more of dimethyl sulfoxide, methanol, and ethanol. The volume to mass ratio of solvent to hyaluronic acid may be 40-60ml:500mg, for example 40ml:500mg, 45ml:500mg, 50ml:500mg, 55ml:500mg or 60ml:500mg.

Preferably, the heating temperature may be 50-70 ℃, e.g. may be 50 ℃, 55 ℃, 60 ℃, 65 ℃ or 70 ℃. Preferably, the alkali is added followed by stirring for 5-20min, e.g. 5min, 10min, 15min or 20min. Preferably, the carboxyl activator is added and stirred for 30min-90min, e.g., 30min, 40min, 50min, 60min, 70min, 80min or 90min. Preferably, addThe reaction is then stirred for 12-36h, for example 12h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h or 36h. Preferably, the volume ratio of water to the solvent used to dissolve the hyaluronic acid upon dilution with water may be (0.8-1.2): 1, for example 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1.

Preferably, the hyaluronic acid, the base, the carboxyl activator andThe molar ratio of (1-1.5): (6-7): (3-4): (0.5-1), alternatively (1-1.5): (6.5-7): (3.5-4): (0.5-1), for example may be 1.32:6.6:3.96:0.66. The molar ratio is optimized, the quantity of carboxyl groups participating in the reaction in the hyaluronic acid is controlled within the range of 10-15%, and the formation of the supramolecular hybrid hydrogel is facilitated. The excessive or small amount of the polymer is unfavorable for the formation of the supermolecule hybridized hydrogel.

Preferably, the dialysis comprises dialysis with sodium chloride solution followed by dialysis with water. Preferably, the concentration of the sodium chloride solution may be 0.05M to 0.15M, for example 0.05M, 0.1M or 0.15M. The dialysis time of the sodium chloride solution may be 12-48 hours, for example 20-30 hours. The water dialysis time may be 6-8 days, for example 6 days, 7 days or 8 days.

Preferably, the compoundsCommercially available or prepared according to methods reported in the literature. For example, can be prepared by a method comprising the step of reacting a compound under an inert atmosphereBenzotriazol-1-yloxy tris (dimethylamino) phosphonium hexafluorophosphate, N-diisopropylethylamine and N-BOC ethylenediamine in solvent, separating by column chromatography, purifying to obtain compound

In some embodiments of the invention, the modification has positively charged groupsThe beta-cyclodextrin of (2) can be prepared by a process comprising the steps of:

Firstly, carrying out iodination on natural beta-cyclodextrin to obtain 6-site periodate beta-cyclodextrin, then heating the 6-site periodate beta-cyclodextrin with sodium azide and sodium iodide in a solvent to obtain 6-site periodate beta-cyclodextrin, then adding ammonium hydroxide under the action of triphenylphosphine to react to obtain 6-site periodate beta-cyclodextrin, and finally reacting with 1H-pyrazole carboxamide hydrochloride to obtain hepta- (6-deoxy-6-guanidyl) -beta-cyclodextrin.

firstly, carrying out iodination on natural beta-cyclodextrin to obtain 6-position periodate beta-cyclodextrin, and then, reacting the 6-position periodate beta-cyclodextrin with 1-methylimidazole to obtain the hepta- (6-deoxy-6-methylimidazole) -beta-cyclodextrin.

firstly, carrying out iodination on natural beta-cyclodextrin to obtain 6-position periodate beta-cyclodextrin, and then, reacting the 6-position periodate beta-cyclodextrin with polyamine (such as ethylenediamine, diethylenetriamine and triethylenetetramine) to obtain the hepta- (6-deoxy-6-polyamine) -beta-cyclodextrin.

In some embodiments of the invention, the inclusion compound solution is prepared by dissolving the arylazo pyrazole modified hyaluronic acid and the beta-cyclodextrin modified with positively charged groups in water and sonicating.

Preferably, the ultrasound time may be 3-10min, for example 3min, 4min, 5min, 6min, 7min, 8min, 9min or 10min.

In some embodiments of the invention, the mixture is prepared by suspending hectorite in water, adding a stripping agent after stirring, and adding the clathrate solution after continuing stirring.

Preferably, the mass ratio of the laponite to the exfoliating agent may be 50mg (1.5-2.0 mg), for example 50mg:1.5mg, 50mg:1.6mg, 50mg:1.7mg, 50mg:1.8mg, 50mg:1.9mg or 50mg:2.0mg.

Preferably, the mass to volume ratio of hectorite to water may be 50mg (1-3 mL), such as 50mg:1mL, 50mg:1.5mL, 50mg:2mL, 50mg:2.5mL, or 50mg:3mL.

Preferably, the hectorite is suspended in water and stirred for 5-20min, such as 5min, 10min, 15min or 20min. Preferably, the stripping agent is added and stirring is continued for 5-20min, such as 5min, 10min, 15min or 20min. Adding the clathrate solution and continuing stirring until the mixture loses fluidity.

In the present invention, the steps of stirring, mixing, reacting, etc. of the present invention are carried out at a temperature of 20 to 30℃unless otherwise specified.

In a third aspect, the present invention provides a pesticide comprising the supramolecular hybrid hydrogel of the first aspect of the invention and an agrochemical loaded thereon.

In some embodiments of the invention, the agrochemical may be one or more of naphthalene acetic acid, gibberellin, indole acetic acid, paclobutrazol, ethephon, and the like.

In a fourth aspect, the present invention provides a method for preparing the pesticide, comprising the steps of:

the supramolecular hybrid hydrogels according to the first aspect of the invention are dried and mixed with agrochemicals.

In some embodiments of the invention, the mass ratio of supramolecular hybrid hydrogels to agrochemicals may be 1 (0.02-0.06), for example, 1:0.02, 1:0.03, 1:0.04, 1:0.05, or 1:0.06.

Compared with the prior art, the invention has the beneficial effects that:

The invention provides an environment-friendly supramolecular hybrid hydrogel with high pesticide release, which is formed by utilizing the supermolecular complexation of a beta-CD cavity and an aryl azo pyrazole group (AAP) and the electrostatic interaction of the surface of hectorite (LP) and a positively charged group. The hydrogel can be loaded with agricultural chemicals, and can control the release of the agricultural chemicals, and the accumulated release amount of the agricultural chemicals can reach more than 60% under the continuous ultraviolet irradiation. In addition, the supermolecule hybridized hydrogel after releasing agricultural chemicals can adsorb heavy metal ions in soil, so that the environmental pollution is reduced, and the environment is protected.

Drawings

FIG. 1 is a schematic representation of the preparation and application of a supramolecular hybrid hydrogel according to an embodiment of the present invention.

FIG. 2 is a ¹ HNMR profile of phenylazo pyrazole modified hyaluronic acid in D ₂ O at 25 ℃.

FIG. 3 (a) is a diagram showing a state where laponite is dispersed in water with the aid of sodium polyacrylate (the inorganic component laponite in the supramolecular hydrogel accounts for 90.54% by weight).

FIG. 3 (b) is a state diagram of the supramolecular hybrid hydrogel of example 1 (LP/HA-AAP-Guano-CD=2/0.21 wt%, LP/HA-AAP-Guano-CD represents the mass percent ratio of inorganic component (hectorite) to organic component (HA-AAP-Guano-CD) in the supramolecular hydrogel.

FIG. 3 (c) is a state diagram of the supramolecular hybrid hydrogel of FIG. 3 (b) after irradiation with 365nm ultraviolet light.

FIG. 3 (d) is a scanning electron microscope image of the supermolecule hybrid hydrogel of example 1 after lyophilization.

FIG. 3 (e) is an injection photograph of the supramolecular hybrid hydrogel of example 1.

FIG. 4 is a Zeta potential analysis chart of each sample.

FIG. 5 (a) shows the storage modulus (G ') and loss modulus (G') of the supramolecular hybrid hydrogels of example 1 as a function of frequency.

FIG. 5 (b) is a chart showing strain sweep testing of the supramolecular hybrid hydrogels of example 1.

FIG. 5 (c) is a continuous step strain test chart of the supramolecular hybrid hydrogel of example 1.

FIG. 5 (d) is a temperature scan test chart of the supramolecular hybrid hydrogel of example 1.

FIG. 6 (a) shows the UV/visible absorption spectrum of HA-AAP-beta-CD inclusion complex under UV irradiation (365 nm).

FIG. 6 (b) shows the UV/visible absorption spectrum of the HA-AAP-beta-CD clathrate under visible light irradiation (520 nm) at 25 ℃.

FIG. 7 (a) shows the UV/visible absorption of NAA in aqueous solutions of 0.01, 0.02, 0.03, 0.04, 0.05 mg/mL.

Fig. 7 (b) shows a standard curve of NAA concentration at λ=282 nm absorption peak.

FIG. 7 (c) shows the cumulative release of NAA from HA-AAP-Guano-CD@LP hydrogel under dark and ultraviolet light.

FIG. 7 (d) shows the UV/visible absorption of FITC in 0.00125, 0.0025, 0.005, 0.01, 0.02mg/mL aqueous solutions.

Fig. 7 (e) shows a standard curve of FITC concentration at the absorption peak at λ=491 nm.

FIG. 7 (f) shows the cumulative release of FITC in the hydrogel under dark and ultraviolet radiation.

FIG. 8 (a) shows representative photographs of cabbage of each treatment group at the end of cultivation, wherein each treatment group was 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free GA group, 4) GA-loaded HA-AAP-Guano-CD@LP hydrogel group.

FIG. 8 (b) shows the germination curves of the control, hA-AAP-Guano-CD@LP hydrogel, GA and GA-loaded HA-AAP-Guano-CD@LP hydrogel treated cabbages.

FIG. 8 (c) shows the stem length and shoot height of the cabbage for each treatment group at the end of cultivation.

FIG. 8 (d) shows the fresh weights of the cabbages of each treatment group at the end of the cultivation.

FIG. 8 (e) shows the dry weight of cabbage for each treatment group at the end of cultivation.

FIG. 9 (a) shows representative photographs of alfalfa from each of the treatment groups 1) the control group, 2) the HA-AAP-Guano-CD@LP hydrogel group, 3) the free GA group, and 4) the GA-loaded HA-AAP-Guano-CD@LP hydrogel group.

FIG. 9 (b) shows the germination curves of the control, hA-AAP-Guano-CD@LP hydrogel, GA and GA-loaded HA-AAP-Guano-CD@LP hydrogel treated alfalfa.

FIG. 9 (c) shows the stem length and shoot height of alfalfa for each treatment group at the end of cultivation.

FIG. 9 (d) shows the fresh weights of alfalfa for each treatment group at the end of cultivation.

FIG. 9 (e) shows the dry weight of alfalfa for each treatment group at the end of the incubation.

FIG. 10 (a) shows representative photographs of cabbage of each treatment group at the end of cultivation, wherein each treatment group is 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free NAA group, 4) NAA-loaded HA-AAP-Guano-CD@LP hydrogel group.

FIG. 10 (b) shows the stem length and shoot height of the cabbage for each treatment group at the end of cultivation.

FIG. 10 (c) shows the fresh weights of the cabbages of each treatment group at the end of the cultivation.

FIG. 10 (d) shows the dry weight of cabbage for each treatment group at the end of cultivation.

FIG. 11 (a) shows representative photographs of alfalfa from each treatment group at the end of the incubation, wherein each treatment group was 1) a control group, 2) a HA-AAP-Guano-CD@LP hydrogel group, 3) a free NAA group, 4) a NAA-loaded HA-AAP-Guano-CD@LP hydrogel group.

FIG. 11 (b) shows the stem length and seedling height of alfalfa in each treatment group at the end of cultivation.

FIG. 11 (c) shows the fresh weights of alfalfa for each treatment group at the end of cultivation.

FIG. 11 (d) shows the dry weight of alfalfa for each treatment group at the end of cultivation.

Fig. 12 (a) shows the adsorption curve of Cu (II) at 25 ℃ for the controlled release sol and the corresponding photograph of the freeze-dried sol after Cu (II) adsorption.

Fig. 12 (b) shows a pseudo-first order kinetic model.

Fig. 12 (c) shows a pseudo-secondary kinetic model.

FIG. 12 (d) shows the UV-visible spectra of CuSO ₄ solutions at 0.002, 0.0025, 0.004, 0.005, 0.01 mg/mL.

Fig. 12 (e) shows a concentration standard curve of Cu (II) at λ=601 nm absorption peak.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

Unless defined otherwise, technical terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The experimental reagents used in the following examples are all conventional biochemical reagents unless otherwise specified, the raw materials, instruments, equipment and the like used in the following examples are all commercially available or available by the existing methods, the experimental reagent dosages are all the reagent dosages in the conventional experimental operation unless otherwise specified, and the experimental methods are all the conventional methods unless otherwise specified.

The main reagents and instruments used in the examples are shown in tables 1-2 below.

TABLE 1 Experimental reagents

Table 2 laboratory apparatus

(1) Preparation of supramolecular hybrid hydrogels

Example 1

(1) Synthesis of (E) -N- (2-aminoethyl) -2- (3, 5-dimethyl-4- (phenyldiazenyl) -1H-pyrazol-1-yl) acetamide

The compound is prepared(516 Mg,0.493 mmol) was dissolved in 20mL of N, N-dimethylformamide, deaerated with N ₂ for 15min, 1.056g of benzotriazol-1-yloxytris (dimethylamino) phosphonium hexafluorophosphate and 1.043mL of N, N-diisopropylethylamine and 384. Mu.LN-BOC ethylenediamine were added to the solution, and reacted for 16h under the protection of room temperature N ₂, the solvent was distilled off, the residue was dissolved in 20mL of ethyl acetate, washed with 20mL of water and then with 20mL of physiological saline, dried over anhydrous magnesium sulfate, distilled off with dichloromethane: methanol (50:1) column chromatography, and the resulting product was purified by stirring overnight at room temperature in 15mL of methanol, 1mL of acetyl chloride, and then separated and purified by dichloromethane: methanol (10:1) column chromatography.

(2) Synthesis of phenylazo pyrazole modified hyaluronic acid (HA-AAP)

Hyaluronic acid was added to 50mL of dimethyl sulfoxide (DMSO)(M=103, n=694) (500 mg,1.32 mmol), heated to 60 ℃, and cooled to room temperature after complete dissolution of HA. Triethylamine (0.92 mL,6.6 mmol) was added and stirred at room temperature for 10min. Ethyl chloroformate (0.377 mL,3.96 mmol) was added thereto, stirring was continued at room temperature for 1h, and then(198.1 Mg,0.66 mmol) and stirring was continued at room temperature for 24h. 50mL of deionized water was added to the system to dilute, and the resulting solution was dialyzed against 0.1M sodium chloride for 24h and then against excess deionized water for 7 days. After lyophilization, phenyl azo pyrazole modified hyaluronic acid yellow powder is obtained.

FIG. 2 is a 1H NMR spectrum of phenylazo pyrazole modified hyaluronic acid. 1H NMR (400 MHz, D ₂ O, ppm): delta 2.02 (s, 3H, HA methyl H), 2.44-2.53 (m, 0.79H, H on pyrazolomethyl group on phenylazo pyrazole), 3.14-4.22 (m, 12.53H, H on HA and phenylazo pyrazole methylene group), 4.41-4.51 (m, 2H, H on HA), 7.48-7.57 (m, 0.60H, H on phenyl group on phenylazo pyrazole), 7.78-7.80 (m, 0.39H, H on phenyl group on phenylazo pyrazole).

FIG. 2 shows characteristic proton signals of phenyl and methyl groups on arylazo pyrazole units around chemical shifts of 7.15-7.80ppm and 2.44-2.53ppm, wherein 2.0ppm and 4.5ppm of proton signals are assigned to HA, indicating successful grafting of AAP onto the HA chains. From the integration of the methyl proton peak area and the n-acetyl proton peak area of HA at 2.0ppm, it can be calculated that one AAP is modified per 7.6 HA polysaccharide units, i.e. about 13% of the HA carboxyl groups react with the AAP.

(3) Synthesis of guanidine-modified beta-cyclodextrin (Guano-CD)

Triphenylphosphine (21 g,80 mmol) and iodine (20.2 g,80 mmol) were first dissolved in DMF (80 mL), natural β -cyclodextrin (4.32 g,26.6 molar equivalents) was added, and the solution was stirred at 80℃for 15h. Concentrated to half volume in vacuo and the pH was adjusted to 9-10. Sodium methoxide in methanol (3M, 30 mL) was added while cooling, and the solution was kept at room temperature for 30min to break the formate formed in the reaction, after which it was poured into ice water (1.5L). The precipitate was collected by filtration to give the 6-periodate-cyclodextrin. The 6-position periodate beta-cyclodextrin is dissolved in DMF, sodium azide and sodium iodide are added and stirred for reaction for 18h at 110 ℃, and then the reaction mixture is cooled to room temperature. And precipitating a reaction product, washing with acetone, and finally drying in vacuum at room temperature to obtain the 6-position total azido beta-cyclodextrin.

Beta-cyclodextrin (1.5 g,1.29 mmol) was dissolved in DMF (2.2 mL). Triphenylphosphine (Ph 3P) (0.36 g,1.37 mmol) was added and stirred vigorously at room temperature for 2h. Ammonium hydroxide (0.26 mL) was then added and stirring continued for 18h. The reaction mixture was then cooled to room temperature. The reaction product precipitated, was washed with acetone (200 mL) and finally dried under vacuum at room temperature to give hepta (6-amino-6-deoxy) - β -cyclodextrin.

Seven (6-amino-6-deoxy) - β -cyclodextrin (0.667 g,0.59 mmol) is dispersed in dry dimethylformamide (0.6 mL), and 1H-pyrazole carboxamide hydrochloride (2.3 eq, 0.72mmol,0.11 g) and N, N-Diisopropylethylamine (DIPEA) (4.65 molar equivalents, 1.45mmol,0.20 mL) are added to the mixture. Stirring is carried out for 8H under a nitrogen atmosphere at 70℃and then the same amounts of 1H-pyrazole carboxamide hydrochloride and DIPEA as before are added for the second time. And stirring was continued under nitrogen at 70 ℃ for 14h. Diethyl ether (15 mL) was then added dropwise, the resulting suspension was stirred for an additional 2h, the solvent was decanted, and the viscous solid collected was dissolved in a very small amount of water (0.3 mL). Ethanol was added to precipitate a white material, which was filtered and dried in vacuo. The precipitate was redissolved in water, the pH was adjusted to 8.5 with sodium bicarbonate, the solution was washed with chloroform (3X 5 mL), then treated with Dowex type I resin (Cl ^- exchanger) and lyophilized to give hepta- (6-deoxy-6-guanidino) -beta-cyclodextrin.

(4) Synthetic clathrate solution

Beta-cyclodextrin (1.7 mg, 1.189. Mu.M) modified with guanidine groups and phenyl azo pyrazole modified hyaluronic acid (3.7 mg, 0.011. Mu.M) were dissolved in 0.5mL of deionized water, and sonicated for 5min to prepare a HA-AAP-Guano-CD inclusion compound solution.

(5) Synthesis of supramolecular hybrid hydrogel HA-AAP-Guano-CD@LP

50Mg of hectorite (LP) was suspended in 2mL of deionized water and stirred at room temperature for 10min, then 1.7mg of 250. Mu.L of sodium polyacrylate solution was added and stirred for 10min, while stirring, the entire amount of clathrate solution prepared in step 4 was added and stirring continued for 10min until the mixture lost fluidity, and then a free-standing supramolecular hybrid hydrogel was formed.

Example 2

A supramolecular hybrid hydrogel was prepared as in example 1, except that step (1) was synthesized using (E) -N- (2-aminoethyl) -2- (3, 5-dimethyl-4- (p-tolyldiazenyl) -1H-pyrazol-1-yl) acetamide

The compound is prepared(516 Mg,0.493 mmol) was dissolved in 20mL of N, N-dimethylformamide, N2 was used for degassing for 15min, 1.056g of benzotriazol-1-yloxytris (dimethylamino) phosphonium hexafluorophosphate and 1.043mL of N, N-diisopropylethylamine and 384. Mu.LN-BOC ethylenediamine were added to the solution, and reacted under the protection of room temperature N2 for 16h, the solvent was distilled off soon, the residue was dissolved in 20mL of ethyl acetate, washed with 20mL of water and then with 20mL of physiological saline, dried over anhydrous magnesium sulfate, distilled off soon, and the obtained product was purified by column chromatography with methylene chloride: methanol (50:1) and dissolved in 15mL of methanol at 0℃in 1mL of acetyl chloride, the ice bath was removed after 1h, the mixture was stirred overnight at room temperature, and then purified by column chromatography with methylene chloride: methanol (10:1).

Example 3

A supramolecular hybrid hydrogel was prepared as in example 1, except that step (1) was synthesized using (E) -N- (2-aminoethyl) -2- (4- ((4-hydroxyphenyl) diazenyl) -3, 5-dimethyl-1H-pyrazol-1-yl) acetamide

Example 4

A supramolecular hybrid hydrogel was prepared as in example 1, except that step (1) was synthesized using (E) -N- (2-aminoethyl) -2- (4- ((4-fluorophenyl) diazenyl) -3, 5-dimethyl-1H-pyrazol-1-yl) acetamide

Example 5

A supramolecular hybrid hydrogel was prepared as in example 1, except that step (3) was synthesized with an imidazole-modified beta-cyclodextrin (Guano-CD)

Triphenylphosphine (21 g,80 mmol) and iodine (20.2 g,80 mmol) were first dissolved in DMF (80 mL), natural β -cyclodextrin (4.32 g,26.6 molar equivalents) was added, and the solution was stirred at 80℃for 15h. Concentrated to half the volume in vacuo and the pH was adjusted to 9-10. Sodium methoxide in methanol (3M, 30 mL) was added while cooling. The solution was kept at room temperature for 30min to break the formate formed in the reaction, after which it was poured into ice water (1.5L). The precipitate was collected by filtration to give the 6-periodate-cyclodextrin. The 6-position periodate β -cyclodextrin (500 mg,0.26 mmol) was dissolved in 1-methylimidazole (3.0 mL,45.0 mmol) and the reaction mixture was stirred under argon at 80℃for 48h. The resulting solution was poured into acetone (100 mL). The precipitate formed was collected by filtration and then recrystallized from water to give a translucent flaky solid of hepta- (6-deoxy-6-methylimidazole) -beta-cyclodextrin.

Example 6

A supramolecular hybrid hydrogel was prepared as in example 1, except that step (3) was synthesized with a poly-amino group modified beta-cyclodextrin (Guano-CD) where t is 0.

Triphenylphosphine (21 g,80 mmol) and iodine (20.2 g,80 mmol) were first dissolved in DMF (80 mL), natural β -cyclodextrin (4.32 g,26.6 molar equivalents) was added, and the solution was stirred at 80℃for 15h. Concentrated to half the volume in vacuo and the pH was adjusted to 9-10. Sodium methoxide in methanol (3M, 30 mL) was added while cooling. The solution was kept at room temperature for 30min to break the formate formed in the reaction, after which it was poured into ice water (1.5L). The precipitate was collected by filtration to give the 6-periodate-cyclodextrin. The 6-position periodate beta-cyclodextrin (2 g,1.05 mmol) and 30mL ethylenediamine were then added to a 100mL dry round bottom flask, the dissolved solids were stirred under nitrogen atmosphere and the temperature was raised to 80 ℃ for 18h with continuous stirring. A portion of the polyamine was removed by rotary evaporation and the residue was added dropwise to acetone (about 200 mL) with stirring. At this time, white precipitate appeared. After filtration, a white solid was obtained and dissolved in a small amount of distilled water. In this manner, the operation was repeated twice, and finally, the white solid obtained by suction filtration was dried in a vacuum oven for 8 hours to obtain a white powdery solid, i.e., the target compound.

Comparative example 1

The preparation was carried out in the same manner as in example 1 except that laponite was replaced with montmorillonite, and as a result, no gel state was observed. It can be seen that hectorite has a significant effect on the gel state formation.

(2) Supermolecular hybrid hydrogel characterization analysis of examples 1-6

As shown in fig. 3 (a), it was confirmed that LP alone was uniformly dispersed in water with the aid of sodium polyacrylate, and no gel state was observed. As shown in FIG. 3 (b), a supramolecular hybrid hydrogel was prepared in example 1. From FIGS. 3 (a) and 3 (b), it can be seen that the arylazo pyrazole groups in HA-AAP can enter the cyclodextrin cavity to enrich the guanidine groups together and promote the interaction of the guanidine groups with the LP surface, thereby forming the supramolecular polysaccharide hybrid hydrogel. As shown in FIG. 3 (c), the supramolecular hybrid hydrogel exhibits a sol phenomenon after irradiation with 365nm ultraviolet rays. As shown in fig. 3 (d), the lyophilized supramolecular hybrid hydrogel exists in the form of a crosslinked porous network, which is critical for the loading of agrochemicals. FIG. 3 (e) shows that the supramolecular hybrid hydrogel is sheared and thinned, and has good injection function.

The results of the other examples are similar to those of example 1.

(3) Zeta potential test of supramolecular hybrid hydrogels of examples 1-6

The Zeta potential was measured using deionized water to prepare Guano-CD, hA-AAP, hectorite nanodispersion (LP), hA-AAP-Guano-CD clathrate, and supramolecular hybrid hydrogel (all from example 1) suspensions of the same concentrations, three replicates per sample, and averaged.

As shown in FIG. 4, the electrostatic interaction between HA-AAP-Guano-CD and LP was verified by Zeta potential test, the Zeta potential of Guano-CD was +13.90mV, the Zeta potential of HA-AAP was-15.23 mV, and the Zeta potential of HA-AAP-Guano-CD inclusion complex was +2.62mV, demonstrating the binding of HA-AAP-Guano-CD to each other by host-guest interaction, and the Zeta potential of HA-AAP-Guano-CD@LP hydrogel increased from-33.7 mV to-29.5 mV relative to the naked LP, indicating that positively charged HA-AAP-Guano-CD inclusion complex was successfully coated on negatively charged LP by electrostatic interaction.

The results of the other examples are similar to those of example 1.

(4) Characterization of the morphology of the supramolecular hybrid hydrogels of examples 1-6

The microscopic morphology of the supramolecular hybrid hydrogels of example 1 was analyzed using a scanning electron microscope. Samples were prepared using the lyophilized hydrogels, and the surfaces thereof were subjected to a metal spraying treatment, and the structural characteristics of the interior of the hydrogels were observed in a scanning electron microscope SEM as shown in fig. 3 (d).

The results of the other examples are similar to those of example 1.

(5) Rheological Property testing of supramolecular hybrid hydrogels of examples 1-6

Firstly, setting different experimental parameters, adding about 1mL of sample to a sample table, setting a gap between a test flat plate and the sample table to be 1mm, moving the test flat plate to a measuring position, scraping redundant sample by a scraper when the sample waiting for scraping is displayed, putting down a heat preservation cover, and starting a test after the temperature is stable. The mechanical properties of the 4 hydrogels were tested respectively (1) frequency sweep test of testing the storage modulus and loss modulus of the hydrogels at 25℃under a constant strain of 0.5% in the frequency range of 0.628-100rad/s, (2) strain sweep test of testing the storage modulus and loss modulus of the hydrogels at 25℃under a constant frequency of 6.28rad/s in the strain range of 0.1% -100%, (3) continuous step strain test of testing the storage modulus and loss modulus of the hydrogels at 25℃under a constant frequency of 6.28rad/s at intervals of 93s in the strain range of 0.1% and 100%, (4) temperature strain test of testing the storage modulus and loss modulus of the hydrogels at a constant strain of 0.1% and a constant frequency of 6.28rad/s in the range of 25℃to 75 ℃.

The mechanical properties of HA-AAP-Guano-CD@LP of example 1 were investigated by rheology testing. FIG. 5 (a) shows the storage modulus (G ') and loss modulus (G') as a function of frequency, with the storage modulus (G ') value of HA-AAP-Guano-CD@LP consistently greater than the loss modulus (G') over a wide frequency range, indicating that HA-AAP-Guano-CD@LP is more stable to formation. Further, strain sweep testing of HA-AAP-Guano-cd@lp as shown in fig. 5 (b), when the strain amplitude sweep is fixed at ω=6.28 rad/s, the hydrogel undergoes a gel-sol phase transition at the critical strain region γ=56.3%, indicating that the gel network structure is disrupted. Further, the continuous step-strain test is shown in fig. 5 (c), where the G' value of the hydrogel is reduced and the hydrogel is converted to a sol state under a larger amplitude oscillating force of γ=100%, ω=6.28 rad/s. When the amplitude is reduced by γ=0.1%, ω=6.28 rad/s, the G' and G "values quickly return to the original values within 95s, and the system returns to the gel state. The thermal stability of HA-AAP-Guano-cd@lp was also tested and the rheological properties at 70 ℃ were determined as in fig. 5 (d), with G' values greater than G "when the temperature was heated from 25 ℃ to 70 ℃, no phase change being observed even when heated to 70 ℃. Unlike other conventional supramolecular hydrogels, the HA-AAP-Guano-cd@lp supramolecular hybrid hydrogels have very high thermal stability, indicating that the photosensitivity of the supramolecular hydrogels is not affected by the heating-cooling process. These results demonstrate that the integration of the HA-AAP-Guano-CD supramolecular complex with the LP nanoclay can produce hybrid hydrogels that are both environmentally friendly and have good mechanical strength and high stability.

The results of the other examples are similar to those of example 1.

(6) Light response experiments of the clathrate of examples 1-6

Taking example 1 as an example, to avoid the effect of guanidine groups on Guano-CD on UV absorption wavelength, a HA-AAP-beta-CD clathrate was prepared using recrystallized beta-CD instead of Guano-CD, and the clathrate was used to verify the light response characteristics of HA-AAP-Guano-CD. The HA-AAP-beta-CD inclusion compound solution is irradiated for a period of time under 365nm ultraviolet light, and ultraviolet visible spectra under different times are measured respectively. And then the HA-AAP-beta-CD inclusion compound solution irradiated by ultraviolet light is irradiated for a period of time under 520nm visible light, and ultraviolet visible spectra in different periods of time are respectively measured again, so that the cis-trans isomerization of the aryl azo pyrazole group is verified.

As shown in FIG. 6, the photo-response characteristics of HA-AAP-beta-CD inclusion compound were studied in deionized water, the cis-trans isomerization and photochromic actions were successfully verified under the alternate irradiation of ultraviolet light and visible light, the absorption peak at 330nm was decreased under the irradiation of 365nm ultraviolet light, a new ultraviolet absorption peak appeared between 400 and 500nm, the color of the solution was gradually deepened, the aryl azo pyrazole unit was changed from cis structure to trans structure, and the ultraviolet/visible absorption spectrum of the system was not changed after the irradiation for 3min, so that the photostable was achieved (as shown in FIG. 6 (a)). Then after the 520nm visible light irradiation is carried out for 13min, the aryl azo pyrazole unit is recovered from the trans structure to the cis structure, and the ultraviolet/visible absorption spectrum is recovered to the previous state, and the color of the system solution is gradually reduced to the original state (as shown in fig. 6 (b)). Aryl azo pyrazole units in cis form tend to bind strongly to β -CD, while trans forms tend to be detached from the cavity. The results indicate that cis-trans isomerisation of the arylazo pyrazole units modulates the association or dissociation of the inclusion complex, resulting in a sol-gel transition of the HA-AAP-Guano-cd@lp hydrogel, releasing the payload.

The preparation method of the HA-AAP-beta-CD inclusion compound solution comprises the following steps:

Recrystallized beta-cyclodextrin (0.9 mg, 0.8. Mu.M) and phenylazopyrazole modified hyaluronic acid (2.4 mg, 0.007. Mu.M, from example 1) were dissolved in 6mL of deionized water and sonicated for 5min to prepare a HA-AAP-beta-CD clathrate solution.

The results of the other examples are similar to those of example 1.

(7) Application studies of supramolecular hybrid hydrogels of examples 1-6

7.1 Supports of agrochemicals on the supramolecular hybrid hydrogels HA-AAP-Guano-CD@LP of examples 1-6

The model pesticides were loaded onto the supermolecule hybrid hydrogel of example 1 using a pre-load method with alpha-naphthylacetic acid (NAA) and Gibberellin (GA) as model pesticides, taking NAA loading as an example. The freeze-dried hydrogel is soaked in 1mg/mL of NAA solution with the concentration of 2.75mL, so that the NAA-loaded hydrogel is obtained after the NAA-loaded hydrogel is fully swelled, and the NAA-loaded hydrogel is freeze-dried for later use. The GA is preloaded in the same manner as NAA. NAA:GA:

load factor (%) =100× (C ₀V₀-C₁V₁)/m

Encapsulation efficiency (%) =100× (C ₀V₀-C₁V₁)/C₀V₀

Wherein C ₀、C₁ is NAA concentration or GA concentration of the solution before and after loading, V ₀ is the volume of the solution before loading, V ₁ is the volume of the solution after loading, and m is the weight of the freeze-dried hydrogel. The concentration of NAA or GA in the solution was determined by UV-visible spectroscopy.

NAA and GA were selected as model pesticides due to the three-dimensional network structure in the hydrogel and preloaded into the network of the hydrogel. According to the formula, the loading rate and the encapsulation rate of the supramolecular hydrogel to NAA are respectively 4.59% and 100%, and the loading rate and the encapsulation rate of the supramolecular hydrogel to GA are respectively 4.59% and 100%.

The results of the other examples are similar to those of example 1.

7.2 Light responsive Release of NAA and GA

The light-responsive release behavior of the supramolecular hybrid hydrogels of example 1 (from experimental section 7.1) loaded with NAA or GA at room temperature was investigated by dialysis. Taking light response release of NAA as an example, placing a sample (namely supermolecule hybridized hydrogel loaded with NAA or GA) with a certain mass into a dialysis bag (the molecular weight cut-off is Mw=500-1000), sealing, soaking in 30mL of deionized water, stirring at room temperature for dialysis, inducing release under 365nm ultraviolet light irradiation, taking the dark sample as a control group, sucking 2mL of dialysate at 0min, 5min, 10min, 20min, 40min, 60min, 80min, 100min, 120min, 140min, 160min, 180min, 200min, 220min and 240min respectively, adding fresh deionized water with the same volume, ensuring that the dialyzed deionized water is always 30mL, measuring absorbance by a standard curve method, and calculating and analyzing the release amount of pesticide.

Experiments were performed by simulating sunlight irradiation with 365nm ultraviolet lamps, and the controlled release behavior under illumination stimulation was studied by periodically recording the ultraviolet-visible spectrum. Based on the calculation method of lambert beer law, the cumulative release rates of NAA and GA are calculated. NAA, among others, is a commonly used broad-spectrum plant growth regulator that promotes cell division and expansion to increase plant root and stem growth. Subsequently, the time dependence and light-triggered release behavior of NAA in supramolecular hydrogels were studied, and the UV-visible absorption spectrum at 282nm at different concentrations was plotted to form NAA standard curves (as shown in FIGS. 7 (a) and (b)), from which it was found that NAA-loaded hydrogels had a cumulative release of 63% after being left in the dark for 4 hours, and a cumulative release of 85% under sustained UV irradiation (as shown in FIG. 7 (c)), indicating that NAA-loaded supramolecular hybrid hydrogels had good UV responsiveness.

Next, in order to demonstrate the diversity of the hydrogels for drug loading, the auxin GA, another auxin, gibberellin (GA), which can stimulate leaf and stem growth by increasing the number of auxins in plants and promoting cell division and expansion, was selected and encapsulated as another model pesticide. Since the ultraviolet-visible absorption peak of GA has a low peak intensity, it is difficult to calculate the cargo and release capacity in supramolecular hydrogels. Therefore, fluorescein Isothiocyanate (FITC) is selected as a model cargo, and the loading capacity and light-operated release behavior of GA in the hydrogel are evaluated, and the experimental steps are the same as NAA. The photo-responsive release behavior of the hydrogels to FITC was evaluated by the same method as for NAA described above, and the UV-visible absorption spectra at 495nm at different concentrations were plotted as FITC standard curves (FIGS. 7 (d) and (e)), from which it was seen that FITC-loaded hydrogels had a cumulative release of 42% after 4 hours of placement in the dark and a cumulative release of 63% under sustained UV irradiation (as shown in FIG. 7 (f)).

The results show that the supermolecule hybridized hydrogel provides a very promising platform for photoinitiated agrochemical release. The light-dependent release not only improves the utilization efficiency of pesticides, but also reduces the toxicity to the environment, which indicates that the HA-AAP-Guano-CD@LP is likely to become a controllable release system for modern agriculture.

The results of the other examples are similar to those of example 1.

7.3 Experiments on plant growth controlled by supramolecular hybrid hydrogels of examples 1-6

After verifying the release of the photoresponsive drug of the supramolecular hybrid hydrogel, the regulation and control capability of the supramolecular hybrid hydrogel on plant growth was continuously studied. The method uses Chinese cabbage and alfalfa as plant models, and co-cultures with supramolecular hybrid hydrogel loaded with agricultural chemicals to study the differences of germination rate, stem length, seedling height, dry weight and fresh weight of seeds, so as to reflect the regulation effect of the supramolecular hybrid hydrogel carrier on plant growth.

Experimental method

Picking full Chinese cabbage seeds and alfalfa seeds respectively, soaking in 2% sodium hypochlorite solution for 5min, washing with sterile water for 3 times to remove sodium hypochlorite on the surfaces of the seeds, soaking the treated seeds in 45 ℃ warm water for 30min, sowing on culture dishes, and repeating for 3 times for 20 seeds per culture dish. Then, 1mL of ultrapure water (control), hA-AAP-Guano-CD@LP hydrogel of example 1, free agrochemical (GA concentration: 0.02mg/mL, NAA concentration: 0.02 mg/mL) and agrochemical-loaded hydrogel (concentration equivalent to free GA and NAA, agrochemicals loaded on the hydrogel in accordance with the method described above) were added to the petri dishes, respectively, GA groups were added on day 0 and day 2, and NAA groups were added on day 2 and day 4 after a certain bud was cultivated. All dishes were incubated for 14h at 25℃under light and 10h in the dark. And (5) periodically recording germination conditions of the cabbage seeds and the alfalfa seeds. After the cultivation, the stem height, plant height, fresh weight and dry weight were measured (NNA group cultivation for 6 days, GA group cultivation for 5 days).

7.3.1 Study of the effect of GA-loaded supramolecular hybrid hydrogels (GA@ hydrogels) on chinese cabbage.

FIG. 8 (a) shows representative photographs of the cabbages of each treatment group, and it can be seen from the figures that the growth of the cabbages of group 4 (GA@ hydrogels) is the best.

As shown in FIG. 8 (b), in the early stage of seed germination, the germination rate of cabbage seeds in the GA@ hydrogel group and the free GA group is higher than that of cabbage seeds in the control group and the HA-AAP-Guano-CD@LP hydrogel group, which shows that under the stimulation of illumination, the GA-loaded supramolecular polysaccharide hybrid hydrogel can release GA with good biological activity, and the seeds treated by the HA-AAP-Guano-CD@LP hydrogel group have no obvious difference from the control group, which shows that the germination rate of the seeds is not obviously influenced by the separate HA-AAP-Guano-CD@LP drug carrier. The germination rate of 4 groups reaches the highest within 28 h. After 5 days of culture, the stem length and plant height of each group were recorded and evaluated.

As shown in FIG. 8 (c), the stem lengths of the free GA group and GA@ hydrogel group were 2.35 times and 2.46 times, respectively, that of the control group, and the plant heights were 1.48 times and 1.94 times, respectively. Meanwhile, the stem length and the plant height of the hydrogel group are slightly higher than those of the control group, which shows that the hydrogel has no obvious promotion effect on the stem length and the plant height, but has good biocompatibility. These phenomena further confirm that GA-loaded HA-AAP-Guano-CD@LP can release GA under the stimulation of light, and GA@ hydrogel has obvious promotion effect on the stem length and plant height of Chinese cabbage. Next, after the cultivation is completed, the fresh weight and dry weight of each group of Chinese cabbage seedlings are recorded and counted for analysis.

As can be seen from fig. 8 (d) and 8 (e), the fresh weight and dry weight of the GA group and GA@ hydrogel group were higher than those of the control group, indicating that GA can enhance organic matter accumulation and promote plant growth.

The results of the other examples are similar to those of example 1.

7.3.2 Study of the effect of GA-loaded supramolecular hybrid hydrogels (GA@ hydrogels) on alfalfa.

Similarly, the promotion effect on alfalfa is consistent with that of Chinese cabbage.

FIG. 9 (a) shows representative photographs of alfalfa from each treatment group, from which it can be seen that alfalfa from group 4 (GA@ hydrogels) grew best.

As shown in FIG. 9 (b), the germination rate of alfalfa treated with GA@ hydrogel group and free GA group was slightly higher than that of control group and hydrogel group at the initial stage of germination.

As shown in FIG. 9 (c), the alfalfa stem length and plant height were measured, the stem lengths of the free GA group and GA@ hydrogel group were 1.61 times and 1.63 times, respectively, that of the control group, and the plant heights were 1.86 times and 1.88 times, respectively, that also confirmed the promotion effect of light-dependent release GA of HA-AAP-Guano-CD@LP supermolecular hybrid hydrogels on alfalfa growth.

As shown in fig. 9 (d) and 9 (e), the fresh weight and dry weight of alfalfa were evaluated, and the fresh weight and dry weight of the free GA and GA@ hydrogel-treated groups were higher than those of the control group, indicating that the accumulation of organic matter of the chinese cabbage after the addition of GA and GA@ hydrogel treatment was enhanced.

The results of the other examples are similar to those of example 1.

7.3.3 Study of the effect of NAA-loaded supramolecular hybrid hydrogels (NAA@hydrogels) on cabbage.

The regulation and control capability of the obtained hydrogel on plant growth is further proved by researching the influence of NAA-loaded HA-AAP-Guano-CD@LP on the growth of Chinese cabbage.

Unlike GA, the main role of NAA is to promote root growth. Thus, the differences in stem length, plant height, dry weight and fresh weight were measured at the end of the culture.

FIG. 10 (a) shows representative photographs of the cabbages of each treatment group, from which it can be seen that the growth of the cabbages of group 4 (NAA@hydrogel) is best.

As shown in FIG. 10 (b), the NAA@hydrogel group has a better promoting effect on plant growth by analyzing the growth results of the Chinese cabbage, namely, the stem length and plant height of the NAA@hydrogel group and the free NAA group are obviously higher than those of the control group, and the plant heights of the NAA@hydrogel group and the free NAA group are respectively 2.22 times and 1.77 times higher than those of the control group, and the corresponding stem lengths are respectively 1.76 times and 1.28 times higher than those of the control group.

Fig. 10 (c) and (d) compare the fresh and dry weights of the cabbages, and the fresh and dry weights of the NAA-loaded hydrogel treatment groups were 1.28 times and 1.26 times, respectively, that of the control group, and also higher than the free NAA treatment group.

The results of the other examples are similar to those of example 1.

7.3.4 Study of the effect of NAA-loaded supramolecular hybrid hydrogels (NAA@hydrogels) on alfalfa.

The effect of NAA-loaded HA-AAP-Guano-CD@LP on alfalfa stem length, plant height, dry weight and fresh weight was evaluated.

As shown in fig. 11 (a) and (b), it can be directly observed that the naa@hydrogel group and the free NAA group grew more vigorously than the alfalfa of the control group and the hydrogel group, the stem length and the plant height of the naa@hydrogel group were 1.76 times and 1.72 times that of the control group respectively, which are obviously higher than those of the free NAA treated group, and the stem length and the plant height of the hydrogel group and the control group are basically consistent, and it is obvious that the naa@hydrogel group and the free NAA group show remarkable growth advantages relative to the control group, and have promotion effect on the growth of the alfalfa.

Statistical analysis was performed on fresh and dry weights of alfalfa as in fig. 11 (c) and (d), with the naa@hydrogel group significantly higher than the other three groups. The method shows that the damage to the internal structure of the hydrogel under the catalysis of illumination can continuously release the naphthylacetic acid drug to promote the growth of alfalfa.

The results of the other examples are similar to those of example 1.

(8) Analysis of adsorption performance of supramolecular hybrid hydrogel to heavy metal ions after releasing agrochemicals

Experimental method

(1) The Cu (II) standard solution preparation reagent comprises 0.5g/mL citric acid solution, 1:1 ammonia water solution and 0.1% dicyclo-ethanone oxalyl-dipalmonds solution (0.5 g dicyclo-ethanone oxalyl-dipalmonds are weighed and added into 50mL ethanol to be warmed to 60 ℃, and the mixture is transferred into a 500mL volumetric flask after being dissolved, and the volume is fixed to a scale mark).

(2) Drawing a Cu (II) standard curve, namely accurately adding 2.0mL, 2.4mL, 2.8mL, 3.2mL and a CuSO ₄ standard solution with the concentration of 10 mug/mL into 5 volumetric flasks of 100mL respectively, sequentially adding the prepared 4mL citric acid, 8mL ammonia water and 20mL bicyclooxalyl dippalm into the standard solution, shaking and shaking uniformly to fix the volume to a scale mark, testing the absorbance by using a double-beam ultraviolet spectrophotometer, and drawing the standard curve.

(3) The supramolecular hybrid hydrogel was loaded with alpha-naphthylacetic acid (NAA) on the supramolecular hybrid hydrogel HA-AAP-Guano-CD@LP of example 1 according to the methods of experimental part 7.1 and 7.2, and induced to release for 4 hours under irradiation of 365nm ultraviolet light, to obtain a hydrogel after NAA release. (confirmation of correctness) the performance of capturing heavy metal ions was tested using hydrogels after NAA release. 5mg of the lyophilized sol was immersed in a 10mLCuSO ₄ mg/mL solution, placed on a constant temperature shaker, and shaken at 25℃for 5h at 100 rpm/min. The concentration of Cu (II) after adsorption was determined by a bis (cyclohexanone) oxalyldihydrazone complex colorimetric method. The absorbance value of Cu (II) at a wavelength of 610nm was measured using a double beam uv spectrophotometer, and the adsorption capacity was calculated as follows using standard curve analysis:

q_t＝(C₀-C_t)V/m

Wherein q _t (mg/g) is the adsorption quantity at time t, C ₀ and C _t (mg/mL) are the initial concentration and the residual concentration of Cu ²⁺ at time t respectively, V (mL) is the volume of Cu ²⁺ solution, and m (g) is the mass of the hydrogel after freeze drying.

Adsorption kinetics the adsorption process was studied by pseudo-primary and pseudo-secondary adsorption kinetics models.

Pseudo first order dynamics model:

log(q_e-q_t)＝logq_e-K₁t/2.303

Pseudo-secondary dynamics model:

t/q_t＝1/K₂q²+t/q_e

Wherein q _e and q _t are respectively the adsorption quantity (mg/g) of heavy metal ions in an equilibrium state and at time t (min), K ₁ is the rate constant of the pseudo-first-order adsorption process (min ^-1);K₂ is the pseudo-second-order rate constant [ g (mg/min) ^-1 ].

Since Cu (II) ions are one of the most toxic metal contaminants to humans and all living systems, cu (II) ions were selected as model ions to evaluate their trapping ability. As the photoresponse of the agrochemical is released, the arylazo pyrazole group is converted from trans to cis, causing dissociation of the host-guest complex and the hydrogel, thereby causing a gel-sol phase transition of the hybrid hydrogel. And the HA chain after the sol still contains excessive carboxyl groups, so that the HA chain can be further used as a potential adsorbent for synergistically adsorbing heavy metal ions.

The standard curves of Cu (II) (FIGS. 12 (d) and (e)) were plotted according to the ultraviolet-visible absorption spectra at 610nm at different concentrations, and as shown in FIG. 12 (a), the adsorption amount was increased from 142.57mg/g to 249.89mg/g in 300min according to the standard curve of Cu (II), and then the adsorption amount was not significantly changed with the increase of the contact time. The results show that as the adsorption time is prolonged, the number of effective adsorption sites on the sol gradually decreases until saturation is reached. Subsequently, kinetic studies were performed on the adsorption process using pseudo-primary and pseudo-secondary models.

As can be seen from fig. 12 (b) and (c) and table 3 below, the correlation coefficient R ² = 0.9978 of the pseudo-secondary model fitting is higher than the correlation coefficient R ² = 0.9734 of the pseudo-primary model fitting, indicating that the adsorption kinetics of the resulting sol to Cu (II) have a good correlation with the pseudo-secondary model. The calculated adsorption capacity of the pseudo-secondary model is 263.16mg/g, which is equivalent to 249.89mg/g of the experimental adsorption capacity. Together, these results demonstrate that the adsorption process is driven by chemical adsorption of Cu (II) ions complexed with the surface of functional groups such as carboxyl groups on the surface of the sol, combined with the photosensitive controlled release phenomenon of agrochemicals, further demonstrating the synergistic adsorption of the prepared sol on heavy metal ions.

TABLE 3 adsorption kinetics model correlation coefficients

The results of the other examples are similar to those of example 1.

In summary, the invention constructs the environment-friendly light-responsive supermolecule hybrid hydrogel based on the host-guest and electrostatic interactions among the aryl azo pyrazole modified hyaluronic acid, the beta-cyclodextrin modified with the positive charge group and the LP, which is used for plant growth regulation and heavy metal ion adsorption, and can effectively load agricultural chemicals into the three-dimensional network structure of the hydrogel, thereby showing good light-responsive pesticide release, plant growth regulation and synergistic adsorption of heavy metal ions. The supermolecule hybridized hydrogel successfully solves three key problems in principle, namely (1) enabling agricultural chemicals to have good biocompatibility, (2) controlling drug release, avoiding excessive use of the agricultural chemicals, and (3) cooperatively adsorbing heavy metal ions, and reducing environmental pollution. The environment-friendly photosensitive polysaccharide-based supermolecule hybrid hydrogel provided by the invention can provide a new choice for improving the utilization efficiency of agricultural chemicals and solving the environmental problems in modern agriculture.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A supramolecular hybrid hydrogel comprising laponite, hyaluronic acid modified with an arylazopyrazole, and β-cyclodextrin modified with a positively charged group;

The arylazopyrazole-modified hyaluronic acid has the following structural formula:

wherein R is methyl, hydroxy or halogen, q is an integer from 0 to 5, m is from 100 to 110, and n is from 690 to 700;

The β-cyclodextrin modified with positively charged groups has the following structural formula:

Wherein, R' is the positively charged group;

The supramolecular hybrid hydrogel is obtained by a preparation method comprising the following steps:

Hyaluronic acid in the presence of alkali Carboxyl activators and Reaction to obtain arylazopyrazole-modified hyaluronic acid, wherein R is methyl, hydroxyl or halogen, q is an integer of 0-5, m is 100-110, and n is 690-700;

dissolving the arylazopyrazole-modified hyaluronic acid and the β-cyclodextrin modified with a positively charged group in a solvent to prepare an inclusion complex solution; and

The hectorite, the stripping agent and the inclusion compound solution are mixed and stirred until the mixture loses fluidity to obtain the supramolecular hybrid hydrogel.

2. The supramolecular hybrid hydrogel according to claim 1, wherein the positively charged group R' is one of the following structures:

Wherein t is an integer from 0 to 2.

3. The supramolecular hybrid hydrogel according to claim 1 or 2, wherein the arylazopyrazole-modified hyaluronic acid is The β-cyclodextrin modified with positively charged groups is

4. The supramolecular hybrid hydrogel according to claim 1 or 2, characterized in that the mass ratio of the arylazopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the hectorite is (0.05-0.1):(0.01-0.05):1.

5. The method for preparing the supramolecular hybrid hydrogel according to any one of claims 1 to 4, characterized in that it comprises the following steps:

6. The preparation method according to claim 5, characterized in that the mass ratio of the arylazopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the hectorite is (0.05-0.1):(0.01-0.05):1.

7. The preparation method according to claim 5 or 6, characterized in that:

The base is one or more of triethylamine, 4-dimethylaminopyridine, and 1-hydroxybenzotriazole;

The carboxyl activator is one or more of ethyl chloroformate, isobutyl chloroformate, and N-hydroxysuccinimide;

The stripping agent is sodium polyacrylate;

The solvent is one or more of water and dimethyl sulfoxide.

8. The preparation method according to claim 5 or 6, characterized in that:

The preparation of the arylazopyrazole modified hyaluronic acid comprises: adding the hyaluronic acid to a solvent, heating to dissolve, cooling to 20-30° C., adding the base, stirring, adding the carboxyl activator, continuing stirring, and adding After the reaction was completed, water was added to dilute the product, dialyzed and then freeze-dried.

9 . The preparation method according to claim 8 , wherein the solvent used to dissolve the hyaluronic acid is one or more of dimethyl sulfoxide, methanol, and ethanol.

10. The preparation method according to claim 8, wherein the hyaluronic acid, the base, the carboxyl activator and The molar ratio is (1-1.5):(6-7):(3-4):(0.5-1).

11. The preparation method according to claim 8, wherein the dialysis comprises: first dialysis with sodium chloride solution, and then dialysis with water;

The preparation of the inclusion complex solution comprises: dissolving the arylazopyrazole-modified hyaluronic acid and the β-cyclodextrin modified with a positively charged group in water, and sonicating;

The preparation of the mixture comprises: suspending hectorite in water, stirring, adding a stripping agent, continuing stirring, and adding the inclusion compound solution.

12 . The preparation method according to claim 5 , wherein the mass ratio of the hectorite to the stripping agent is 50 mg:(1.5-2.0 mg).

13. A pesticide, characterized by comprising the supramolecular hybrid hydrogel according to any one of claims 1 to 4 and agricultural chemicals loaded thereon.

14. The method for preparing the pesticide according to claim 13, characterized in that it comprises the following steps:

The supramolecular hybrid hydrogel according to any one of claims 1 to 4 is dried and then mixed with agricultural chemicals.