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

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

Technical Field

[0001] The present invention relates to the technical field of hydrogels, and in particular to a supramolecular hybrid hydrogel and a preparation method thereof, a pesticide and a preparation method thereof. Background Art

[0002] In recent years, controlled-release technology has been recognized as a promising strategy for improving pesticide utilization efficiency and addressing environmental issues due to its advantages in reducing pesticide losses, reducing pesticide usage, and minimizing environmental pollution. Currently, pesticide delivery systems based on mesoporous silica nanoparticles, carbon nanomaterials, polymer micelles, and metal / metal oxide nanoparticles have been constructed and have improved pesticide utilization efficiency. However, the preparation of these systems still faces challenges such as poor raw material biodegradability, toxic organic solvents, and insufficient pesticide release.

[0003] Therefore, it is necessary to develop an environmentally friendly pesticide controlled-release system with high pesticide release rate. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an environmentally friendly supramolecular hybrid hydrogel with high pesticide release.

[0005] Another object of the present invention is to provide a method for preparing the supramolecular hybrid hydrogel.

[0006] Another object of the present invention is to provide a pesticide comprising the supramolecular hybrid hydrogel.

[0007] Another object of the present invention is to provide a method for preparing the pesticide.

[0008] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0009] In a first aspect, the present invention provides a supramolecular hybrid hydrogel comprising laponite, hyaluronic acid modified with an arylazopyrazole, and β-cyclodextrin modified with a positively charged group;

[0010] The arylazopyrazole-modified hyaluronic acid has the following structural formula:

[0011]

[0012] 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;

[0013] The β-cyclodextrin modified with positively charged groups has the following structural formula:

[0014]

[0015] Wherein, R' is the positively charged group.

[0016] The supramolecular hybrid hydrogel of the present invention is an environmentally friendly, light-responsive polysaccharide-based supramolecular hybrid hydrogel that can load agrochemicals and control their release. Under continuous ultraviolet irradiation, the cumulative release of agrochemicals can reach over 60%. Furthermore, after releasing the agrochemicals, the supramolecular hybrid hydrogel can also adsorb heavy metal ions in the soil, reducing environmental pollution.

[0017] The present invention utilizes the supramolecular complexation of β-cyclodextrin (β-CD) cavity with arylazopyrazole groups (AAP) and the electrostatic interaction between the surface of laponite (LP) and positively charged groups to construct a hyaluronic acid-based supramolecular hybrid hydrogel. This system has some inherent characteristics: (1) Nanoclay is a promising drug delivery material. The incorporation of LP and the biocompatible polymer hyaluronic acid (HA) can form a stable three-dimensional hydrogel network with good mechanical strength and performance, including high drug loading, improved water solubility and biocompatibility of agrochemicals, and sustained drug release; (2) With the goal of stimuli-responsive release of agrochemicals, the host-guest pair of β-cyclodextrin and AAP is introduced as a stimuli-responsive site because it is photoresponsive to ultraviolet light, which enables the supramolecular hybrid hydrogel to control the release through photo-controlled gel-sol transition; (3) After the release of pesticides from HA, its abundant carboxyl groups can further form complexes with heavy metal ions. Therefore, the supramolecular hybrid hydrogel of the present invention may provide a new option for precision agriculture.

[0018] In some embodiments of the present invention, m may be 100, 101, 102, 103, 104, 105, 106, 107, 108, 109 or 110. Preferably, m is 100-105.

[0019] In some embodiments of the present invention, n may be 690, 691, 692, 693, 694, 695, 696, 697, 698, 699 or 700. Preferably, n is 690-695.

[0020] In the present invention, q represents the number of substituents R on the phenyl group. Preferably, q is an integer of 0-2.

[0021] In some embodiments of the present invention, the positively charged group R' is one of the following structures:

[0022] wherein t is an integer from 0 to 2. Preferably, the positively charged group R' is The positive charge on the guanidine group easily combines with the negatively charged hectorite through electrostatic interaction, which is conducive to the construction of a cross-linked porous hydrogel structure.

[0023] In some embodiments of the present invention, the arylazopyrazole-modified hyaluronic acid is The β-cyclodextrin modified with positively charged groups is

[0024] The "aryl" in "arylazopyrazole" is preferably an unsubstituted phenyl group. Due to the limited size of the β-CD cavity, the selection of an unsubstituted phenylazopyrazole is more conducive to the complexation of this group with the β-CD cavity, thereby forming a stable host-guest pair.

[0025] In some embodiments of the present invention, the mass ratio of the arylazopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the laponite is (0.05-0.1):(0.01-0.05):1.

[0026] Controlling the mass ratio of the three substances is beneficial to the construction of supramolecular hybrid hydrogels with three-dimensional network structures.

[0027] In some specific embodiments, the mass ratio of the aromatic azopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the hectorite can 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.

[0028] In some embodiments of the present invention, R may be a methyl group, q may be an integer from 0 to 2, m may be 103, and n may be 694.

[0029] In a second aspect, the present invention provides a method for preparing the supramolecular hybrid hydrogel, see Figure 1 , including the following steps:

[0030] 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;

[0031] 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

[0032] 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.

[0033] The preparation method of the present invention has simple process and strong repeatability and is suitable for large-scale industrial production.

[0034] In some embodiments of the present invention, the mass ratio of the arylazopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the laponite is (0.05-0.1):(0.01-0.05):1.

[0035] In some specific embodiments, the mass ratio of the aromatic azopyrazole-modified hyaluronic acid, the β-cyclodextrin modified with positively charged groups, and the hectorite can 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.

[0036] In some embodiments of the present invention, the base can be one or more of triethylamine, 4-dimethylaminopyridine, and 1-hydroxybenzotriazole. The amino reaction in

[0037] In some embodiments of the present invention, the carboxyl activator can be one or more of ethyl chloroformate, isobutyl chloroformate, and N-hydroxysuccinimide. Activating the carboxyl groups in hyaluronic acid with a carboxyl activator can significantly increase the reactivity of the carboxyl groups, allowing them to react more quickly with The amino reaction in the reaction can increase the reaction rate, shorten the reaction time and save time costs.

[0038] In some embodiments of the present invention, the exfoliating agent may be sodium polyacrylate. Hectorite is a layered material, and the addition of an exfoliating agent can exfoliate the hectorite into negatively charged nanosheets, which helps enhance the electrostatic interaction between the positively charged groups and the hectorite and stabilize the structure of the supramolecular hybrid hydrogel.

[0039] In some embodiments of the present invention, the solvent used to prepare the inclusion compound solution may be one or more of water and dimethyl sulfoxide.

[0040] In some embodiments of the present invention, 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.

[0041] Preferably, the solvent used to dissolve the hyaluronic acid is one or more of dimethyl sulfoxide, methanol, and ethanol. The volume-to-mass ratio of the solvent to the hyaluronic acid may be 40-60 mL:500 mg, for example, 40 mL:500 mg, 45 mL:500 mg, 50 mL:500 mg, 55 mL:500 mg, or 60 mL:500 mg.

[0042] Preferably, the heating temperature is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C. Preferably, the base is added and stirred for 5-20 minutes, for example, 5 minutes, 10 minutes, 15 minutes or 20 minutes. Preferably, the carboxyl activator is added and stirred for 30 minutes to 90 minutes, for example, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes or 90 minutes. Preferably, the base is added and stirred for 5-20 minutes, for example, 5 minutes, 10 minutes, 15 minutes or 20 minutes. The mixture is stirred and reacted for 12-36 hours, for example, 12 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours or 36 hours. Preferably, when diluted with water, the volume ratio of water to the solvent for dissolving the hyaluronic acid can be (0.8-1.2):1, for example, 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1.

[0043] Preferably, the hyaluronic acid, the base, the carboxyl activator and The molar ratio can be (1-1.5):(6-7):(3-4):(0.5-1), or alternatively (1-1.5):(6.5-7):(3.5-4):(0.5-1), for example, 1.32:6.6:3.96:0.66. By optimizing this molar ratio, the proportion of carboxyl groups in the hyaluronic acid involved in the reaction is controlled within the range of 10%-15%, which is conducive to the formation of supramolecular hybrid hydrogels. Excessive or insignificant proportions are not conducive to the formation of supramolecular hybrid hydrogels.

[0044] Preferably, the dialysis comprises: first dialysis with a sodium chloride solution, then dialysis with water. Preferably, the concentration of the sodium chloride solution can be 0.05M-0.15M, such as 0.05M, 0.1M, or 0.15M. The sodium chloride solution dialysis time can be 12-48 hours, such as 20-30 hours. The water dialysis time can be 6-8 days, such as 6 days, 7 days, or 8 days.

[0045] Preferably, the compound It can be purchased or prepared according to the method reported in the literature. For example, it can be prepared by a method comprising the following steps: under an inert atmosphere, Benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, N,N-diisopropylethylamine and N-BOC ethylenediamine react in a solvent; after column chromatography separation and purification, a compound is obtained.

[0046] In some embodiments of the present invention, the modification has a positively charged group The β-cyclodextrin can be prepared by a method comprising the following steps:

[0047] First, natural β-cyclodextrin is iodinated to obtain 6-periodinated β-cyclodextrin; then, it is heated with sodium azide and sodium iodide in a solvent to obtain 6-periodinated β-cyclodextrin; then, ammonium hydroxide is added under the action of triphenylphosphine to react to obtain 6-periodinated β-cyclodextrin, and finally, it is reacted with 1H-pyrazolecarboxamide hydrochloride to obtain heptadecano-(6-deoxy-6-guanidino)-β-cyclodextrin.

[0048] In some embodiments of the present invention, the modification has a positively charged group The β-cyclodextrin can be prepared by a method comprising the following steps:

[0049] First, natural beta-cyclodextrin is iodinated to obtain 6-periodinated beta-cyclodextrin; then the 6-periodinated beta-cyclodextrin is reacted with 1-methylimidazole to obtain heptakis-(6-deoxy-6-methylimidazole)-beta-cyclodextrin.

[0050] In some embodiments of the present invention, the modification has a positively charged group The β-cyclodextrin can be prepared by a method comprising the following steps:

[0051] First, natural β-cyclodextrin is iodinated to obtain 6-periodinated β-cyclodextrin; then the 6-periodinated β-cyclodextrin is reacted with polyamine (such as ethylenediamine, diethylenetriamine, triethylenetetramine) to obtain heptakis-(6-deoxy-6-polyamine)-β-cyclodextrin.

[0052] In some embodiments of the present invention, the preparation of the inclusion complex solution comprises: dissolving the arylazopyrazole-modified hyaluronic acid and the β-cyclodextrin modified with positively charged groups in water, and sonicating.

[0053] Preferably, the ultrasonic time may be 3-10 min, for example, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0054] In some embodiments of the present invention, the preparation of the mixture comprises: suspending hectorite in water, stirring, adding a stripping agent, and continuing to stir, then adding the inclusion compound solution.

[0055] Preferably, the mass ratio of the hectorite to the stripping agent may be 50 mg:(1.5-2.0 mg), for example, 50 mg:1.5 mg, 50 mg:1.6 mg, 50 mg:1.7 mg, 50 mg:1.8 mg, 50 mg:1.9 mg or 50 mg:2.0 mg.

[0056] Preferably, the mass volume ratio of the hectorite and water may be 50 mg:(1-3 mL), for example, 50 mg:1 mL, 50 mg:1.5 mL, 50 mg:2 mL, 50 mg:2.5 mL or 50 mg:3 mL.

[0057] Preferably, the hectorite is suspended in water and stirred for 5-20 minutes, for example, 5 minutes, 10 minutes, 15 minutes, or 20 minutes. Preferably, the stripping agent is added and stirring is continued for 5-20 minutes, for example, 5 minutes, 10 minutes, 15 minutes, or 20 minutes. The inclusion compound solution is added and stirring is continued until the mixture loses fluidity.

[0058] In the present invention, unless otherwise specified, the stirring, mixing, reaction and other operation steps of the present invention are carried out at a temperature of 20-30°C.

[0059] In a third aspect, the present invention provides a pesticide comprising the supramolecular hybrid hydrogel according to the first aspect of the present invention and agricultural chemicals loaded thereon.

[0060] In some embodiments of the present invention, the agricultural chemicals may be one or more of naphthaleneacetic acid, gibberellin, indoleacetic acid, paclobutrazol, ethephon, and the like.

[0061] In a fourth aspect, the present invention provides a method for preparing the pesticide, comprising the following steps:

[0062] The supramolecular hybrid hydrogel according to the first aspect of the present invention is dried and then mixed with agricultural chemicals.

[0063] In some embodiments of the present invention, the mass ratio of the supramolecular hybrid hydrogel to the agricultural chemical 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.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention provides an environmentally friendly supramolecular hybrid hydrogel with high pesticide release. This hydrogel is constructed by combining the supramolecular complexation of a β-CD cavity with an arylazopyrazole group (AAP) and the electrostatic interaction between a laponite (LP) surface and positively charged groups. The hydrogel can be loaded with agrochemicals and its release can be controlled. Under continuous ultraviolet irradiation, the cumulative release of the agrochemicals can reach over 60%. Furthermore, after releasing the agrochemicals, the supramolecular hybrid hydrogel can also adsorb heavy metal ions in the soil, reducing environmental pollution and enhancing environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1Schematic diagram of the preparation and application of supramolecular hybrid hydrogel according to one embodiment of the present invention.

[0067] Figure 2 The hyaluronic acid modified with phenylazopyrazole was dissolved in D2O at 25℃. 1 HNMR spectrum.

[0068] Figure 3 (a) is a diagram of the state of hectorite dispersed in water with the assistance of sodium polyacrylate (the mass percentage of the inorganic component hectorite in the supramolecular hydrogel is 90.54 weight %).

[0069] Figure 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 percentage ratio of the inorganic component (hectorite) to the organic component (HA-AAP-Guano-CD) in the supramolecular hydrogel).

[0070] Figure 3 (c) Figure 3 (b) Schematic diagram of the supramolecular hybrid hydrogel after irradiation with 365nm ultraviolet light.

[0071] Figure 3 (d) is a scanning electron microscope image of the supramolecular hybrid hydrogel after freeze-drying in Example 1.

[0072] Figure 3 (e) is a photo of the injection of the supramolecular hybrid hydrogel of Example 1.

[0073] Figure 4 Zeta potential analysis diagram of each sample.

[0074] Figure 5 (a) shows the storage modulus (G') and loss modulus (G") of the supramolecular hybrid hydrogel of Example 1 as a function of frequency.

[0075] Figure 5 (b) shows the strain scanning test diagram of the supramolecular hybrid hydrogel of Example 1.

[0076] Figure 5 (c) shows the continuous step strain test diagram of the supramolecular hybrid hydrogel of Example 1.

[0077] Figure 5 (d) shows the temperature scanning test diagram of the supramolecular hybrid hydrogel of Example 1.

[0078] Figure 6(a) shows the UV / visible absorption spectrum of HA-AAP-β-CD inclusion complex under UV irradiation (365 nm).

[0079] Figure 6 (b) shows the UV / visible absorption spectrum of the HA-AAP-β-CD inclusion complex under visible light irradiation (520 nm) at 25°C.

[0080] Figure 7 (a) UV / visible absorption of NAA in 0.01, 0.02, 0.03, 0.04, and 0.05 mg / mL aqueous solutions is given.

[0081] Figure 7 (b) shows the standard curve of NAA concentration at the absorption peak of λ = 282 nm.

[0082] Figure 7 (c) Cumulative release of NAA from HA-AAP-Guano-CD@LP hydrogel in the dark and under UV light irradiation is given.

[0083] Figure 7 (d) The UV / visible absorption of FITC in 0.00125, 0.0025, 0.005, 0.01, and 0.02 mg / mL aqueous solutions is given.

[0084] Figure 7 (e) shows the standard curve of FITC concentration at the absorption peak of λ = 491 nm.

[0085] Figure 7 (f) shows the cumulative release of FITC from the hydrogel in the dark and under UV irradiation.

[0086] Figure 8 (a) Representative photos of Chinese cabbage in each treatment group at the end of culture are shown; the treatment groups are: 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free GA group, and 4) GA-loaded HA-AAP-Guano-CD@LP hydrogel group.

[0087] Figure 8 (b) The germination curves of cabbage treated with the control group, HA-AAP-Guano-CD@LP hydrogel, GA, and GA-loaded HA-AAP-Guano-CD@LP hydrogel are shown.

[0088] Figure 8 (c) shows the stem length and seedling height of the Chinese cabbage in each treatment group at the end of the culture.

[0089] Figure 8 (d) shows the fresh weight of the Chinese cabbage of each treatment group at the end of the culture.

[0090] Figure 8 (e) Shows the dry weight of the Chinese cabbage of each treatment group at the end of the culture.

[0091] Figure 9 (a) Representative photos of alfalfa in each treatment group are shown; the treatment groups are: 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free GA group, and 4) HA-AAP-Guano-CD@LP hydrogel group loaded with GA.

[0092] Figure 9 (b) Shows the germination curves of alfalfa treated with the control group, HA-AAP-Guano-CD@LP hydrogel, GA, and GA-loaded HA-AAP-Guano-CD@LP hydrogel.

[0093] Figure 9 (c) shows the stem length and seedling height of alfalfa in each treatment group at the end of cultivation.

[0094] Figure 9 (d) shows the fresh weight of alfalfa in each treatment group at the end of incubation.

[0095] Figure 9 (e) shows the dry weight of alfalfa in each treatment group at the end of incubation.

[0096] Figure 10 (a) Representative photos of Chinese cabbage in each treatment group at the end of culture are shown; the treatment groups are: 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free NAA group, and 4) NAA-loaded HA-AAP-Guano-CD@LP hydrogel group.

[0097] Figure 10 (b) shows the stem length and seedling height of the Chinese cabbage in each treatment group at the end of the culture.

[0098] Figure 10 (c) shows the fresh weight of the Chinese cabbage of each treatment group at the end of the culture.

[0099] Figure 10 (d) shows the dry weight of the Chinese cabbage in each treatment group at the end of the incubation period.

[0100] Figure 11 (a) Representative photos of alfalfa in each treatment group at the end of culture are shown; the treatment groups are: 1) control group, 2) HA-AAP-Guano-CD@LP hydrogel group, 3) free NAA group, and 4) NAA-loaded HA-AAP-Guano-CD@LP hydrogel group.

[0101] Figure 11(b) shows the stem length and seedling height of alfalfa in each treatment group at the end of cultivation.

[0102] Figure 11 (c) shows the fresh weight of alfalfa in each treatment group at the end of incubation.

[0103] Figure 11 (d) shows the dry weight of alfalfa in each treatment group at the end of incubation.

[0104] Figure 12 (a) shows the adsorption curve of Cu(II) by the controlled-release sol at 25°C and the corresponding photograph of the freeze-dried sol after adsorption of Cu(II).

[0105] Figure 12 (b) The pseudo-first-order kinetic model is given.

[0106] Figure 12 (c) The pseudo-second-order kinetic model is given.

[0107] Figure 12 (d) UV-visible spectra of CuSO4 solutions at 0.002, 0.0025, 0.004, 0.005, and 0.01 mg / mL are given.

[0108] Figure 12 (e) shows the concentration standard curve of Cu(II) at the absorption peak of λ=601nm. DETAILED DESCRIPTION

[0109] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0110] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following examples are all commercially available or can be obtained through existing methods; the amounts of the experimental reagents used, unless otherwise specified, are the amounts used in conventional experimental procedures; and the experimental methods, unless otherwise specified, are all conventional methods.

[0111] The main reagents and instruments used in the examples are shown in Table 1-2 below.

[0112] Table 1 Experimental reagents

[0113]

[0114]

[0115] Table 2 Experimental instruments

[0116]

[0117] (1) Preparation of supramolecular hybrid hydrogels

[0118] Example 1

[0119] (1) Synthesis of (E)-N-(2-aminoethyl)-2-(3,5-dimethyl-4-(phenyldiazenyl)-1H-pyrazol-1-yl)acetamide

[0120]

[0121] The compound The product (516 mg, 0.493 mmol) was dissolved in 20 mL of N,N-dimethylformamide and degassed with N2 for 15 min. Then, 1.056 g of benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, 1.043 mL of N,N-diisopropylethylamine and 384 μL of N-BOC ethylenediamine were added to the solution and reacted under N2 protection at room temperature for 16 h. The solvent was evaporated and the residue was dissolved in 20 mL of ethyl acetate, washed with 20 mL of water and then with 20 mL of normal saline, dried over anhydrous magnesium sulfate, evaporated and separated and purified by column chromatography with dichloromethane:methanol (50:1). The product was dissolved in 15 mL of methanol and 1 mL of acetyl chloride at 0°C. The ice bath was removed after 1 h. The mixture was stirred at room temperature overnight and then separated and purified by column chromatography with dichloromethane:methanol (10:1).

[0122] (2) Synthesis of phenylazopyrazole-modified hyaluronic acid (HA-AAP)

[0123]

[0124] Add hyaluronic acid to 50 mL of dimethyl sulfoxide (DMSO) (m=103,n=694)(500mg,1.32mmol), heated to 60℃, HA was completely dissolved and then cooled to room temperature. Triethylamine (0.92mL,6.6mmol) was added and stirred at room temperature for 10min. Ethyl chloroformate (0.377mL,3.96mmol) was added and stirred at room temperature for 1h. (198.1 mg, 0.66 mmol) was added and stirred at room temperature for 24 h. 50 mL of deionized water was added to dilute the system. The resulting solution was dialyzed against 0.1 M sodium chloride for 24 h and then against excess deionized water for 7 days. After lyophilization, a yellow powder of phenylazopyrazole-modified hyaluronic acid was obtained.

[0125] Figure 2 1H NMR spectrum of hyaluronic acid modified with phenylazopyrazole. 1H NMR (400 MHz, D2O, ppm): δ 2.02 (s, 3H, H of HA methyl group), 2.44-2.53 (m, 0.79H, H of the pyrazolemethyl group on phenylazopyrazole), 3.14-4.22 (m, 12.53H, H of the methylene groups of HA and phenylazopyrazole), 4.41-4.51 (m, 2H, H of HA), 7.48-7.57 (m, 0.60H, H of the phenyl group on phenylazopyrazole), 7.78-7.80 (m, 0.39H, H of the phenyl group on phenylazopyrazole).

[0126] Figure 2 Characteristic proton signals for the phenyl and methyl groups of the arylazopyrazole units were detected near chemical shifts of 7.15-7.80 ppm and 2.44-2.53 ppm, respectively. The proton signals at 2.0 ppm and 4.5 ppm were assigned to HA, indicating that AAP was successfully grafted onto the HA chain. The integration of the HA methyl proton peak area at 2.0 ppm and the n-acetyl proton peak area indicated that one AAP was modified for every 7.6 HA polysaccharide units, meaning that approximately 13% of the HA carboxyl groups reacted with AAP.

[0127] (3) Synthesis of β-cyclodextrin modified with guanidine groups (Guano-CD)

[0128]

[0129] First, triphenylphosphine (21 g, 80 mmol) and iodine (20.2 g, 80 mmol) were dissolved in DMF (80 mL). Native β-cyclodextrin (4.32 g, 26.6 molar equivalents) was added, and the solution was stirred at 80°C for 15 h. The solution was concentrated in vacuo to half its volume, and the pH was adjusted to 9-10. A 3 M solution of sodium methoxide in methanol (30 mL) was added while cooling. The solution was kept at room temperature for 30 min to destroy the formate formed during the reaction, after which it was poured into ice water (1.5 L). The precipitate was collected by filtration to obtain 6-periodinated β-cyclodextrin. The 6-periodinated β-cyclodextrin was then dissolved in DMF, and sodium azide and sodium iodide were added. The reaction was stirred at 110°C for 18 h, after which the reaction mixture was cooled to room temperature. The reaction product precipitated, washed with acetone, and finally dried in vacuo at room temperature to obtain 6-periodinated β-cyclodextrin.

[0130] Dissolve 6-position fully azidated β-cyclodextrin (1.5 g, 1.29 mmol) in DMF (2.2 mL). Add triphenylphosphine (Ph3P) (0.36 g, 1.37 mmol) and stir vigorously at room temperature for 2 hours. Then, add ammonium hydroxide (0.26 mL) and continue stirring for 18 hours. The reaction mixture is then cooled to room temperature. The reaction product precipitates, which is washed with acetone (200 mL) and finally dried under vacuum at room temperature to yield heptakis(6-amino-6-deoxy)-β-cyclodextrin.

[0131] Heptakis(6-amino-6-deoxy)-β-cyclodextrin (0.667 g, 0.59 mmol) was dispersed in dry dimethylformamide (0.6 mL), and 1H-pyrazolecarboxamide hydrochloride (2.3 equivalents, 0.72 mmol, 0.11 g) and N,N-diisopropylethylamine (DIPEA) (4.65 molar equivalents, 1.45 mmol, 0.20 mL) were added to the mixture. The mixture was stirred at 70°C under a nitrogen atmosphere for 8 hours, followed by a second addition of the same amounts of 1H-pyrazolecarboxamide hydrochloride and DIPEA. Stirring was continued at 70°C under nitrogen for 14 hours. Ether (15 mL) was then added dropwise, and the resulting suspension was stirred for an additional 2 hours. The solvent was then decanted, and the collected sticky solid was dissolved in a minimal amount of water (0.3 mL). Ethanol was added to precipitate a white substance, which was then filtered and dried under vacuum. The precipitate was redissolved in water, the pH was adjusted to 8.5 with sodium bicarbonate, the solution was washed with chloroform (3 x 5 mL), and then washed with Dowex I resin (Cl - Exchange agent) and freeze-dried to obtain heptakis-(6-deoxy-6-guanidino)-β-cyclodextrin.

[0132] (4) Synthesis of inclusion compound solution

[0133] β-cyclodextrin modified with guanidine group (1.7 mg, 1.189 μM) and hyaluronic acid modified with phenylazopyrazole (3.7 mg, 0.011 μM) were dissolved in 0.5 mL of deionized water and sonicated for 5 min to prepare HA-AAP-Guano-CD inclusion complex solution.

[0134] (5) Synthesis of supramolecular hybrid hydrogel HA-AAP-Guano-CD@LP

[0135] 50 mg of laponite (LP) was suspended in 2 mL of deionized water and stirred at room temperature for 10 min. Then, 1.7 mg of sodium polyacrylate solution (250 μL) was added and stirred for 10 min. During stirring, the entire amount of the inclusion complex solution prepared in step 4 was added and stirred for another 10 min until the mixture lost its fluidity. A self-supporting supramolecular hybrid hydrogel was formed.

[0136] Example 2

[0137] The supramolecular hybrid hydrogel was prepared according to the method of Example 1, except that (E)-N-(2-aminoethyl)-2-(3,5-dimethyl-4-(p-tolyldiazenyl)-1H-pyrazol-1-yl)acetamide was synthesized in step (1).

[0138]

[0139] The compound The product (516 mg, 0.493 mmol) was dissolved in 20 mL of N,N-dimethylformamide and degassed with N2 for 15 min. Then, 1.056 g of benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, 1.043 mL of N,N-diisopropylethylamine and 384 μL of N-BOC ethylenediamine were added to the solution and reacted under N2 protection at room temperature for 16 h. The solvent was evaporated and the residue was dissolved in 20 mL of ethyl acetate, washed with 20 mL of water and then with 20 mL of normal saline, dried over anhydrous magnesium sulfate, evaporated and separated and purified by column chromatography with dichloromethane:methanol (50:1). The product was dissolved in 15 mL of methanol and 1 mL of acetyl chloride at 0°C. The ice bath was removed after 1 h. The mixture was stirred at room temperature overnight and then separated and purified by column chromatography with dichloromethane:methanol (10:1).

[0140] Example 3

[0141] Supramolecular hybrid hydrogel was prepared according to the method of Example 1, except that (E)-N-(2-aminoethyl)-2-(4-((4-hydroxyphenyl)diazenyl)-3,5-dimethyl-1H-pyrazol-1-yl)acetamide was synthesized in step (1).

[0142]

[0143] The compound The product (516 mg, 0.493 mmol) was dissolved in 20 mL of N,N-dimethylformamide and degassed with N2 for 15 min. Then, 1.056 g of benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, 1.043 mL of N,N-diisopropylethylamine and 384 μL of N-BOC ethylenediamine were added to the solution and reacted under N2 protection at room temperature for 16 h. The solvent was evaporated and the residue was dissolved in 20 mL of ethyl acetate, washed with 20 mL of water and then with 20 mL of normal saline, dried over anhydrous magnesium sulfate, evaporated and separated and purified by column chromatography with dichloromethane:methanol (50:1). The product was dissolved in 15 mL of methanol and 1 mL of acetyl chloride at 0°C. The ice bath was removed after 1 h. The mixture was stirred at room temperature overnight and then separated and purified by column chromatography with dichloromethane:methanol (10:1).

[0144] Example 4

[0145] The supramolecular hybrid hydrogel was prepared according to the method of Example 1, except that (E)-N-(2-aminoethyl)-2-(4-((4-fluorophenyl)diazenyl)-3,5-dimethyl-1H-pyrazol-1-yl)acetamide was synthesized in step (1).

[0146]

[0147] The compound The product (516 mg, 0.493 mmol) was dissolved in 20 mL of N,N-dimethylformamide and degassed with N2 for 15 min. Then, 1.056 g of benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, 1.043 mL of N,N-diisopropylethylamine and 384 μL of N-BOC ethylenediamine were added to the solution and reacted under N2 protection at room temperature for 16 h. The solvent was evaporated and the residue was dissolved in 20 mL of ethyl acetate, washed with 20 mL of water and then with 20 mL of normal saline, dried over anhydrous magnesium sulfate, evaporated and separated and purified by column chromatography with dichloromethane:methanol (50:1). The product was dissolved in 15 mL of methanol and 1 mL of acetyl chloride at 0°C. The ice bath was removed after 1 h. The mixture was stirred at room temperature overnight and then separated and purified by column chromatography with dichloromethane:methanol (10:1).

[0148] Example 5

[0149] The supramolecular hybrid hydrogel was prepared according to the method of Example 1, except that the β-cyclodextrin modified with imidazole groups (Guano-CD) was synthesized in step (3).

[0150]

[0151] First, triphenylphosphine (21g, 80mmol) and iodine (20.2g, 80mmol) were dissolved in DMF (80mL), natural β-cyclodextrin (4.32g, 26.6 molar equivalents) was added, and the solution was stirred at 80°C for 15h. The mixture was concentrated in vacuo to half the volume and the pH was adjusted to 9-10. A methanol solution of sodium methoxide (3M, 30mL) was added and cooled simultaneously. The solution was kept at room temperature for 30min to destroy the formate formed in the reaction, after which it was poured into ice water (1.5L). The precipitate was collected by filtration to obtain 6-periodinated β-cyclodextrin. 6-periodinated β-cyclodextrin (500mg, 0.26mmol) was then dissolved in 1-methylimidazole (3.0mL, 45.0mmol), and the reaction mixture was stirred at 80°C under an argon atmosphere for 48h. The resulting solution was poured into acetone (100mL). The formed precipitate was collected by filtration and then recrystallized from water to give heptakis-(6-deoxy-6-methylimidazole)-β-cyclodextrin as a translucent flaky solid.

[0152] Example 6

[0153] The supramolecular hybrid hydrogel was prepared according to the method of Example 1, except that, in step (3), β-cyclodextrin modified with multiple amino groups (Guano-CD) was synthesized, wherein t was 0.

[0154]

[0155] First, triphenylphosphine (21g, 80mmol) and iodine (20.2g, 80mmol) were dissolved in DMF (80mL), natural β-cyclodextrin (4.32g, 26.6 molar equivalents) was added, and the solution was stirred at 80°C for 15h. The mixture was concentrated in vacuo to half the volume and the pH was adjusted to 9-10. A methanol solution of sodium methoxide (3M, 30mL) was added and cooled simultaneously. The solution was kept at room temperature for 30min to destroy the formate formed in the reaction, after which it was poured into ice water (1.5L). The precipitate was collected by filtration to obtain 6-periodinated β-cyclodextrin. 6-periodinated β-cyclodextrin (2g, 1.05mmol) and 30mL of ethylenediamine were added to a 100mL dry round-bottom flask, the solid was dissolved by stirring under a nitrogen atmosphere, and the temperature was raised to 80°C and stirred for 18h. A portion of polyamines was removed by rotary evaporation, and the residue was added dropwise to acetone (about 200 mL) under agitation. At this time, a white precipitate appeared. After filtration, a white solid was obtained and dissolved in a small amount of distilled water. In this way, the operation was repeated twice. Finally, the white solid obtained by suction filtration was dried in a vacuum drying oven for 8 hours to obtain a white powdery solid, which was the target compound.

[0156] Comparative Example 1

[0157] The preparation was carried out according to the method of Example 1, except that hectorite was replaced by montmorillonite. As a result, no gel state was observed. It can be seen that hectorite has an important influence on the formation of the gel state.

[0158] (2) Characterization and Analysis of Supramolecular Hybrid Hydrogels of Examples 1-6

[0159] like Figure 3 As shown in (a), it was confirmed that the LP alone was uniformly dispersed in water with the aid of sodium polyacrylate, and no gel state was observed. Figure 3 As shown in (b), a supramolecular hybrid hydrogel was prepared in Example 1. Figure 3 (a) and Figure 3 (b) It can be seen that the aromatic azopyrazole groups in HA-AAP can enter the cyclodextrin cavity, enriching the guanidine groups and promoting the interaction between the guanidine groups and the LP surface, thereby forming a supramolecular polysaccharide hybrid hydrogel. Figure 3 As shown in (c), the supramolecular hybrid hydrogel exhibits a sol phenomenon after irradiation with 365nm ultraviolet light. Figure 3 As shown in (d), the freeze-dried supramolecular hybrid hydrogel exists in the form of a cross-linked porous network, which is crucial for the loading of agrochemicals. Figure 3 (e) Shows the shear thinning of the supramolecular hybrid hydrogel with good injectability.

[0160] The results of other examples are similar to those of Example 1.

[0161] (3) Zeta potential test of supramolecular hybrid hydrogels of Examples 1-6

[0162] Deionized water was used to prepare suspensions of Guano-CD, HA-AAP, laponite nanodispersion (LP), HA-AAP-Guano-CD inclusion complex, and supramolecular hybrid hydrogel (all from Example 1) at the same concentrations for testing the Zeta potential. Each sample was tested three times as a parallel experiment, and the average value was taken.

[0163] like Figure 4As shown in the figure, the electrostatic interaction between HA-AAP-Guano-CD and LP was verified by Zeta potential test. The Zeta potential of Guano-CD was +13.90 mV, the Zeta potential of HA-AAP was -15.23 mV, and the Zeta potential of HA-AAP-Guano-CD inclusion complex was +2.62 mV, which proved that HA-AAP-Guano-CD were bound to each other through host-guest interaction. The zeta potential of HA-AAP-Guano-CD@LP hydrogel relative to bare LP increased from -33.7 mV to -29.5 mV, indicating that the positively charged HA-AAP-Guano-CD inclusion complex was successfully coated on the negatively charged LP through electrostatic interaction.

[0164] The results of other examples are similar to those of Example 1.

[0165] (4) Morphological Characterization of the Supramolecular Hybrid Hydrogels of Examples 1-6

[0166] The microscopic morphology of the supramolecular hybrid hydrogel of Example 1 was analyzed using a scanning electron microscope. The freeze-dried hydrogel was used to prepare a sample, and its surface was gold-sprayed and placed under a scanning electron microscope (SEM) to observe the structural characteristics of the hydrogel. Figure 3 (d) shown.

[0167] The results of other examples are similar to those of Example 1.

[0168] (5) Rheological properties test of supramolecular hybrid hydrogels of Examples 1-6

[0169] First, set different experimental parameters, add about 1 mL of sample to the sample stage, set the gap between the test plate and the sample stage to 1 mm, move the test plate to the measurement position, and when the display shows "waiting for scraping sample", use a scraper to scrape off the excess sample, put down the insulation cover, and start the test after the temperature stabilizes. The mechanical properties of four types of hydrogels were tested separately: (1) Frequency sweep test: The storage modulus and loss modulus of the hydrogel were tested at a constant strain of 0.5% at 25°C in the frequency range of 0.628-100 rad / s; (2) Strain sweep test: The storage modulus and loss modulus of the hydrogel were tested at a constant frequency of 6.28 rad / s at 25°C in the strain range of 0.1%-100%; (3) Continuous step strain test: The storage modulus and loss modulus of the hydrogel were tested alternately at a constant frequency of 6.28 rad / s at 25°C in the strain range of 0.1% and 100% with an interval of 93 s; (4) Temperature strain test: The storage modulus and loss modulus of the hydrogel were tested at a constant strain of 0.1% and a constant frequency of 6.28 rad / s in the range of 25°C-75°C.

[0170] The mechanical properties of HA-AAP-Guano-CD@LP of Example 1 were studied through rheological testing. Figure 5 (a) shows the curves of storage modulus (G') and loss modulus (G") changing with frequency. In a wide frequency range, the storage modulus (G') value of HA-AAP-Guano-CD@LP is always greater than the loss modulus (G"), which indicates that the formation of HA-AAP-Guano-CD@LP is relatively stable. In addition, the strain sweep test of HA-AAP-Guano-CD@LP is shown in Figure 2. Figure 5 As shown in (b), when the strain amplitude sweep is fixed at ω = 6.28 rad / s, the hydrogel undergoes a gel-sol phase transition in the critical strain region γ = 56.3%, indicating that the gel network structure is destroyed. In addition, the continuous step strain test is as follows Figure 5 (c) shows that under the action of a large amplitude oscillating force of γ = 100%, ω = 6.28 rad / s, the G' value of the hydrogel decreases and the hydrogel transforms into a sol state. When the amplitude is reduced to γ ​​= 0.1%, ω = 6.28 rad / s, the G' and G" values ​​quickly return to their original values ​​within 95 s, and the system returns to the gel state. Figure 5 (d) The thermal stability of HA-AAP-Guano-CD@LP was also tested and the rheological properties at 70°C were determined. When the temperature was heated from 25°C to 70°C, the G' value was greater than G", and no phase transition was observed even at 70°C. Unlike other traditional supramolecular hydrogels, the HA-AAP-Guano-CD@LP supramolecular hybrid hydrogel has high thermal stability, indicating that the photosensitivity of the supramolecular hydrogel is not affected by the heating-cooling process. These results confirm that the integration of HA-AAP-Guano-CD supramolecular complexes with LP nanoclay can prepare hybrid hydrogels that are both environmentally friendly and have good mechanical strength and high stability.

[0171] The results of other examples are similar to those of Example 1.

[0172] (6) Light response experiment of inclusion complexes of Examples 1-6

[0173] Taking Example 1 as an example, to avoid the effect of the guanidino group on Guano-CD on the ultraviolet absorption wavelength, recrystallized β-CD was used instead of Guano-CD to prepare an HA-AAP-β-CD inclusion complex. This inclusion complex was used to verify the photoresponse characteristics of HA-AAP-Guano-CD. The HA-AAP-β-CD inclusion complex solution was irradiated under 365nm ultraviolet light for a period of time, and the UV-visible spectra at different time periods were measured. The UV-irradiated HA-AAP-β-CD inclusion complex solution was then irradiated under 520nm visible light for a period of time, and the UV-visible spectra at different time periods were again measured to verify the cis-trans isomerization of the arylazopyrazole group.

[0174] like Figure 6 As shown in Figure 2, the photoresponse properties of the HA-AAP-β-CD inclusion complex were studied in deionized water. The cis-trans isomerization and photochromic behavior were successfully verified under alternating irradiation of ultraviolet and visible light. Under irradiation of 365 nm ultraviolet light, the absorption peak at 330 nm decreased, while a new ultraviolet absorption peak appeared between 400-500 nm. The color of the solution also gradually deepened, indicating that the aromatic azopyrazole unit changed from a cis structure to a trans structure. After irradiation for 3 minutes, the UV / visible absorption spectrum of the system no longer changed, thus achieving photostable state (as shown in Figure 2). Figure 6 (a)). Then, after 13 min of 520 nm visible light irradiation, the aromatic azopyrazole unit recovered from the trans structure to the cis structure, and the UV / visible absorption spectrum returned to its previous state, and the color of the system solution gradually lightened to its original state (as shown in FIG. Figure 6 (b)). The cis-structured arylazopyrazole unit readily binds strongly to β-CD, while the trans-structure tends to escape from the cavity. The results indicate that the cis-trans isomerization of the arylazopyrazole unit regulates the association or dissociation of the inclusion complex, leading to a sol-gel transition in the HA-AAP-Guano-CD@LP hydrogel and the release of the payload.

[0175] Preparation method of HA-AAP-β-CD inclusion complex solution:

[0176] Recrystallized β-cyclodextrin (0.9 mg, 0.8 μM) and phenylazopyrazole-modified hyaluronic acid (2.4 mg, 0.007 μM, from Example 1) were dissolved in 6 mL of deionized water and sonicated for 5 min to prepare a HA-AAP-β-CD inclusion complex solution.

[0177] The results of other examples are similar to those of Example 1.

[0178] (7) Application research of supramolecular hybrid hydrogels of Examples 1-6

[0179] 7.1 Loading of Agrochemicals on the Supramolecular Hybrid Hydrogel HA-AAP-Guano-CD@LP of Examples 1-6

[0180] α-Naphthylacetic acid (NAA) and gibberellin (GA) were used as model pesticides and pre-loaded onto the supramolecular hybrid hydrogel of Example 1, with NAA loading being used as an example. The freeze-dried hydrogel was immersed in 2.75 mL of a 1 mg / mL NAA solution to allow it to fully swell, yielding an NAA-loaded hydrogel, which was then freeze-dried for subsequent use. The pre-loading method for GA was the same as for NAA. NAA: GA:

[0181] Load factor (%) = 100 × (C0V0 - C1V1) / m

[0182] Encapsulation efficiency (%) = 100 × (C0V0-C1V1) / C0V0

[0183] Where C0 and C1 are the NAA or GA concentrations in the solution before and after loading; V0 is the volume of the solution before loading, and V1 is the volume of the solution after loading; and m is the weight of the freeze-dried hydrogel. The NAA or GA concentration in the solution was determined using UV-visible spectroscopy.

[0184] Due to the three-dimensional network structure of the hydrogel, NAA and GA were selected as model pesticides and pre-loaded into the hydrogel network. According to the formula, the loading rate and encapsulation efficiency of the supramolecular hydrogel for NAA were 4.59% and 100%, respectively, and the loading rate and encapsulation efficiency of the supramolecular hydrogel for GA were 4.59% and 100%, respectively.

[0185] The results of other examples are similar to those of Example 1.

[0186] 7.2 Light-responsive release of NAA and GA

[0187] The photoresponsive release behavior of the supramolecular hybrid hydrogel of Example 1 loaded with NAA or GA (from Experimental Section 7.1) at room temperature was investigated using dialysis. Taking the photoresponsive release of NAA as an example, a certain mass of sample (i.e., supramolecular hybrid hydrogel loaded with NAA or GA) was placed in a dialysis bag (molecular weight cutoff: Mw = 500-1000), sealed, and immersed in 30 mL of deionized water. Dialysis was performed at room temperature with stirring. Release was induced under 365 nm UV light. Using a dark-treated sample as a control group, 2 mL of dialysate was drawn at 0 min, 5 min, 10 min, 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min, and 240 min, respectively. The same volume of fresh deionized water was then added to ensure that the dialyzed deionized water volume was always 30 mL. The absorbance was measured using the standard curve method, and the release of the pesticide was calculated and analyzed.

[0188] The experiment was conducted using a 365nm UV lamp to simulate sunlight, and the UV-visible spectrum was recorded regularly to study the controlled release behavior under light stimulation. Based on the calculation method of Lambert-Beer's law, the cumulative release rate of NAA and GA was calculated. Among them, NAA is a commonly used broad-spectrum plant growth regulator that promotes cell division and expansion to increase the growth of plant roots and stems. Subsequently, the time-dependent and light-triggered release behavior of NAA in supramolecular hydrogels was studied, and the UV-visible absorption spectrum at 282nm at different concentrations was used to draw a standard curve of NAA (such as Figure 7 (a) and (b) show that the NAA standard curve shows that the cumulative release of the NAA-loaded hydrogel after being placed in the dark for 4 hours is 63%; while under continuous ultraviolet irradiation, the cumulative release is 85% (as shown in Figure 7 (c) shows that the supramolecular hybrid hydrogel loaded with NAA has good UV responsiveness.

[0189] Next, in order to prove that the hydrogel has diversity in loading drugs, the plant growth hormone GA was selected for verification. Gibberellic acid (GA) is another plant growth hormone that can stimulate the growth of leaves and stems by increasing the amount of growth hormone in plants and promoting cell division and expansion. It is encapsulated as another model pesticide. Since the UV-visible absorption peak of GA has a low peak intensity, it is difficult to calculate the loading and release capacity in the supramolecular hydrogel. Therefore, fluorescein isothiocyanate (FITC) was selected as a model cargo to evaluate the loading capacity and light-controlled release behavior of GA in the hydrogel. The experimental steps are the same as NAA. The same method as the above-mentioned NAA was used to evaluate the light-responsive release behavior of the hydrogel to FITC, and the UV-visible absorption spectrum at 495nm at different concentrations was used to draw a standard curve of FITC ( Figure 7 (d) and (e)), the FITC standard curve shows that the cumulative release of the FITC-loaded hydrogel after being placed in the dark for 4 hours is 42%; while the cumulative release under continuous ultraviolet irradiation is 63% (as shown in Figure 2). Figure 7 (f)).

[0190] These results demonstrate that this supramolecular hybrid hydrogel provides a promising platform for light-triggered release of agrochemicals. This light-dependent release not only improves the utilization efficiency of the pesticide but also reduces its environmental toxicity, suggesting that HA-AAP-Guano-CD@LP has the potential to become a controlled release system for modern agriculture.

[0191] The results of other examples are similar to those of Example 1.

[0192] 7.3 Examples 1-6 Supramolecular hybrid hydrogel Plant growth regulation experiment

[0193] After verifying the photoresponsive drug release of supramolecular hybrid hydrogels, we continued to investigate their ability to regulate plant growth. We used cabbage and alfalfa as plant models, co-culturing them with supramolecular hybrid hydrogels loaded with agrochemicals. We studied differences in seed germination rate, stem length, seedling height, dry weight, and fresh weight to demonstrate the regulatory effects of the supramolecular hybrid hydrogel carrier on plant growth.

[0194] Experimental methods

[0195] Plump cabbage and alfalfa seeds were selected and soaked in a 2% sodium hypochlorite solution for 5 minutes. The seeds were then rinsed three times with sterile water to remove the sodium hypochlorite from the seed surface. The treated seeds were then soaked in 45°C warm water for 30 minutes and sown in Petri dishes, with 20 seeds per dish, repeated three times. Subsequently, 1 mL of ultrapure water (control group), the HA-AAP-Guano-CD@LP hydrogel from Example 1, free agrochemicals (GA concentration: 0.02 mg / mL, NAA concentration: 0.02 mg / mL), and agrochemical-loaded hydrogels (at concentrations equivalent to free GA and NAA, loaded onto the hydrogels according to the method described above) were added to the Petri dishes. The GA group was added on days 0 and 2, respectively, while the NAA group was added on days 2 and 4, after a certain number of buds had formed. All Petri dishes were incubated at 25°C in the light for 14 hours and in the dark for 10 hours. The germination of the cabbage and alfalfa seeds was recorded regularly. After culture, the stem height, plant height, fresh weight and dry weight were measured (NNA group cultured for 6 days, GA group cultured for 5 days).

[0196] 7.3.1 Study the effect of GA-loaded supramolecular hybrid hydrogel (GA@hydrogel) on Chinese cabbage.

[0197] Figure 8 (a) shows representative photos of the cabbages in each treatment group. It can be seen from the figure that the cabbages in group 4 (GA@hydrogel) have the best growth.

[0198] like Figure 8 As shown in (b), during the early stages of seed germination, the GA@hydrogel and free GA groups exhibited higher germination rates than the control and HA-AAP-Guano-CD@LP hydrogel groups, demonstrating that under light stimulation, the GA-loaded supramolecular polysaccharide hybrid hydrogel can release GA with excellent bioactivity. However, the HA-AAP-Guano-CD@LP hydrogel-treated seeds showed no significant difference from the control group, indicating that the HA-AAP-Guano-CD@LP drug carrier alone had no significant effect on seed germination. Germination rates in all four groups reached their highest within 28 hours. After five days of culture, stem length and plant height were recorded and evaluated.

[0199] like Figure 8 As shown in (c), the stem lengths of the free GA group and the GA@hydrogel group were 2.35 times and 2.46 times that of the control group, respectively, and the plant heights were 1.48 times and 1.94 times that of the control group, respectively. At the same time, the stem length and plant height of the hydrogel group were slightly higher than those of the control group, indicating that the hydrogel had no significant promoting effect on stem length and plant height, but had good biocompatibility. These phenomena further confirmed that GA-loaded HA-AAP-Guano-CD@LP can release GA under light stimulation, and that GA@hydrogel has a significant promoting effect on the stem length and plant height of Chinese cabbage. Next, after the culture was completed, the fresh weight and dry weight of each group of Chinese cabbage seedlings were recorded and statistically analyzed.

[0200] from Figure 8 (d) and Figure 8 (e) It can be seen that 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.

[0201] The results of other examples are similar to those of Example 1.

[0202] 7.3.2 Study the effect of GA-loaded supramolecular hybrid hydrogel (GA@hydrogel) on alfalfa.

[0203] Similarly, the promoting effect on alfalfa is consistent with that on Chinese cabbage.

[0204] Figure 9 (a) shows representative photos of alfalfa in each treatment group. It can be seen from the figure that the growth of alfalfa in group 4 (GA@hydrogel) is the best.

[0205] like Figure 9 (b) At the early stage of germination, the germination rates of alfalfa treated with GA@hydrogel and free GA were slightly higher than those in the control and hydrogel groups.

[0206] like Figure 9 As shown in (c), the stem length and plant height of alfalfa were measured. The stem lengths of the free GA group and the GA@hydrogel group were 1.61 times and 1.63 times that of the control group, respectively, and the plant heights were 1.86 times and 1.88 times that of the control group, respectively. This also confirms the light-dependent release of GA from the HA-AAP-Guano-CD@LP supramolecular hybrid hydrogel that promotes the growth of alfalfa.

[0207] like Figure 9 (d) and Figure 9 (e) The fresh weight and dry weight of alfalfa were evaluated. The fresh weight and dry weight of the free GA and GA@hydrogel treatment groups were higher than those of the control group, indicating that the organic matter accumulation of Chinese cabbage was enhanced after the addition of GA and GA@hydrogel.

[0208] The results of other examples are similar to those of Example 1.

[0209] 7.3.3 Study the effect of NAA-loaded supramolecular hybrid hydrogel (NAA@hydrogel) on cabbage.

[0210] By studying the effect of NAA-loaded HA-AAP-Guano-CD@LP on the growth of Chinese cabbage, the regulatory ability of the obtained hydrogel on plant growth was further confirmed.

[0211] Unlike GA, the main effect of NAA is to promote root growth. Therefore, the differences in stem length, plant height, dry weight, and fresh weight were measured at the end of the culture.

[0212] Figure 10 (a) shows representative photos of cabbage in each treatment group. It can be seen from the figure that the cabbage in group 4 (NAA@hydrogel) has the best growth.

[0213] like Figure 10 As shown in (b), the growth results of cabbage were analyzed. The NAA@hydrogel group had a good promoting effect on plant growth, that is, the stem length and plant height of the NAA@hydrogel group and the free NAA group were significantly higher than those of the control group. The plant height of the NAA@hydrogel group and the free NAA group was 2.22 times and 1.77 times higher than that of the control group, respectively, and the corresponding stem lengths were 1.76 and 1.28 times that of the control group, respectively.

[0214] Figure 10 (c) and (d), the fresh weight and dry weight of cabbage were compared. The fresh weight and dry weight of the NAA-loaded hydrogel-treated group were 1.28 times and 1.26 times that of the control group, respectively, which were also higher than those of the free NAA-treated group.

[0215] The results of other examples are similar to those of Example 1.

[0216] 7.3.4 Study the effect of NAA-loaded supramolecular hybrid hydrogel (NAA@hydrogel) on alfalfa.

[0217] The effects of NAA-loaded HA-AAP-Guano-CD@LP on the stem length, plant height, dry weight, and fresh weight of alfalfa were evaluated.

[0218] like Figure 11As shown in (a) and (b), it can be directly observed that the alfalfa in the NAA@hydrogel group and the free NAA group grew more vigorously than the control group and the hydrogel group. The stem length and plant height of the NAA@hydrogel group were 1.76 times and 1.72 times that of the control group, respectively, which were significantly higher than those of the free NAA treatment group. The stem length and plant height of the hydrogel group and the control group were basically the same. It is obvious that the NAA@hydrogel group and the free NAA group showed significant growth advantages compared with the control group, and promoted the growth of alfalfa.

[0219] like Figure 11 (c) and (d) showed that the fresh and dry weights of alfalfa in the NAA@hydrogel group were significantly higher than those in the other three groups. This suggests that the internal structure of the hydrogel is disrupted by light, allowing the sustained release of naphthaleneacetic acid to promote alfalfa growth.

[0220] The results of other examples are similar to those of Example 1.

[0221] (8) Analysis of the adsorption performance of heavy metal ions by supramolecular hybrid hydrogels after releasing agrochemicals

[0222] Experimental methods

[0223] (1) Preparation of Cu(II) standard solution: 0.5 g / mL citric acid solution, 1:1 ammonia solution by volume, 0.1% dicyclohexanone oxalyl disuccinate solution (weigh 0.5 g of dicyclohexanone oxalyl disuccinate, add it to 50 mL of ethanol, warm to 60°C, dissolve it, transfer it to a 500 mL volumetric flask, and dilute to the mark).

[0224] (2) Preparation of Cu(II) standard curve: Accurately add 2.0 mL, 2.4 mL, 2.8 mL, 3.2 mL, and 4 mL of 10 μg / mL CuSO4 standard solution into five 100 mL volumetric flasks, respectively. Then, add 4 mL of citric acid, 8 mL of ammonia water, and 20 mL of dicyclohexanone oxalyl dipalmitate prepared above to the standard solution in sequence. Shake the solution to the mark and measure the absorbance using a double-beam UV spectrophotometer to draw the standard curve.

[0225] (3) Adsorption of Cu(II) by supramolecular hybrid hydrogel: According to the methods of Experimental Sections 7.1 and 7.2 above, Supramolecular hybrid hydrogel HA-AAP-Guano-CD@LP loadedα-Naphthylacetic acid (NAA) was induced to release under 365nm ultraviolet light for 4h to obtain a hydrogel after NAA release. (Confirm correct) The performance of the hydrogel after NAA release was tested to capture heavy metal ions. 5mg of freeze-dried sol was immersed in 10mL CuSO4 solution with a concentration of 1mg / mL, placed on a constant temperature oscillator, and shaken at 25℃ and 100rpm / min for 5h. The concentration of Cu(II) after adsorption was determined by bis(cyclohexanone)oxalodihydrazone complex colorimetry. The absorbance value of Cu(II) at a wavelength of 610nm was measured using a double-beam ultraviolet spectrophotometer, and the standard curve was used for analysis. The adsorption capacity was calculated as follows:

[0226] q t =(C0-C t )V / m

[0227] Where q t (mg / g) is the adsorption amount at time t; C0 and C t (mg / mL) Cu 2+ The initial concentration and residual concentration at time t; V (mL) is Cu 2+ The volume of the solution, m(g) is the mass of the hydrogel after freeze-drying.

[0228] Adsorption kinetics: Pseudo-first-order and pseudo-second-order adsorption kinetic models were used to study the adsorption process.

[0229] Pseudo-first-order kinetic model:

[0230] log(q e -q t )=logq e -K1t / 2.303

[0231] Pseudo-second-order kinetic model:

[0232] t / q t =1 / K2q 2 +t / q e

[0233] Where q e and q t are the adsorption capacity of heavy metal ions at equilibrium and time t (min) (mg / g); K1 is the rate constant of pseudo-first-order adsorption process (min -1 ); K2 is the pseudo-second-order rate constant [g (mg / min) -1 ].

[0234] Since Cu(II) ions are one of the most toxic metal pollutants to humans and all living systems, they were chosen as a model ion to evaluate their capture capabilities. Following the photoresponsive release of the agrochemical, the arylazopyrazole groups transform from trans to cis, leading to dissociation of the host-guest complex and the hydrogel, thus inducing a gel-sol phase transition in the hybrid hydrogel. Furthermore, the excess carboxyl groups on the HA chains after the sol phase transition further suggest that they could serve as a potential adsorbent for the synergistic adsorption of heavy metal ions.

[0235] The standard curve of Cu(II) was drawn based on the UV-visible absorption spectra at 610 nm at different concentrations ( Figure 12 (d) and (e)), such as Figure 12 As shown in (a), based on the standard curve for Cu(II), the adsorption capacity increased from 142.57 mg / g to 249.89 mg / g within 300 min, then remained stable with increasing contact time. These results indicate that the number of effective adsorption sites on the sol gradually decreased with increasing adsorption time until saturation was reached. The adsorption process was then kinetically investigated using pseudo-first-order and pseudo-second-order models.

[0236] from Figure 12 (b) and (c) and Table 3 below show that the correlation coefficient R 2 =0.9978, which is higher than the correlation coefficient R of the pseudo-first-order model fitting. 2 =0.9734, indicating that the adsorption kinetics of Cu(II) by the prepared sol correlate well with the pseudo-second-order model. The calculated adsorption capacity of 263.16 mg / g based on the pseudo-second-order model is comparable to the experimental adsorption capacity of 249.89 mg / g. These results confirm that the adsorption process is driven by chemical adsorption via complexation of Cu(II) ions with surface functional groups such as carboxyl groups on the sol. Combined with the photosensitized controlled release of agricultural chemicals, this further demonstrates the synergistic adsorption of heavy metal ions by the prepared sol.

[0237] Table 3 Correlation coefficients of adsorption kinetics model

[0238]

[0239] The results of other examples are similar to those of Example 1.

[0240] In summary, the present invention constructs an environmentally friendly photoresponsive supramolecular hybrid hydrogel based on the host-guest and electrostatic interactions between hyaluronic acid modified with aromatic azopyrazoles, β-cyclodextrin modified with positively charged groups, and LP for plant growth regulation and heavy metal ion adsorption. It can effectively load agricultural chemicals into the three-dimensional network structure of the hydrogel, thereby exhibiting good photoresponsive pesticide release, plant growth regulation, and synergistic adsorption of heavy metal ions. The supramolecular hybrid hydrogel successfully solves three key problems in principle: (1) ensuring good biocompatibility of agricultural chemicals; (2) controlling drug release to avoid excessive use of agricultural chemicals; and (3) synergistic adsorption of heavy metal ions to reduce environmental pollution. The environmentally friendly photosensitive polysaccharide-based supramolecular hybrid hydrogel of the present invention may provide a new option for improving the utilization efficiency of agricultural chemicals and solving environmental problems in modern agriculture.

[0241] The foregoing description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed herein are intended to be encompassed within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A supramolecular hybrid hydrogel, characterized in that: These include laponite, arylazopyrazole-modified hyaluronic acid, and β-cyclodextrin modified with positively charged groups; 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, characterized in that 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, characterized in that 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 beta-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: The following steps are involved: 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; as well as 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.

6. The preparation method according to claim 5, characterized in that The mass ratio of the arylazopyrazole-modified hyaluronic acid, the beta-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, characterized in that 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, characterized in that 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, characterized in that The dialysis comprises: first dialysis with sodium chloride solution, 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, characterized in that The mass ratio of the hectorite to the stripping agent is 50 mg:(1.5-2.0 mg).

13. A pesticide, characterized in that The invention comprises 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: The following steps are involved: The supramolecular hybrid hydrogel according to any one of claims 1 to 4 is dried and then mixed with agricultural chemicals.

Images