Multi-network antibacterial hydrogel and application thereof

Abstract

The invention provides a multi-network antibacterial hydrogel and application thereof, a preparation method comprises the following steps: dispersing microporous silk fibers fixed with CuS nano-enzyme in a gallic acid grafted echinophora coerulea polysaccharide aqueous solution, stirring, and then carrying out ultrasonic shearing; adding a carboxymethyl chitosan solution, and uniformly stirring; freezing in a dry ice / acetone bath for freeze drying to obtain composite aerogel; soaking in a phytic acid aqueous solution; taking out, and continuously carrying out cross-linking reaction in a drying oven. According to the invention, a triple network interpenetrating structure composed of the microporous silk fiber immobilized with the CuS nano-enzyme, the gallic acid grafted echinophora coerulea polysaccharide and the carboxymethyl chitosan is adopted, and the cross-linked composite structure is uniformly distributed in the hydrogel, so that strong interaction can be provided, and the hydrogel is endowed with excellent mechanical properties; the compound has good inhibiting and killing effects on staphylococcus aureus, escherichia coli, acinetobacter baumannii and fusarium Sulawanii.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials, and in particular to a multi-network antibacterial hydrogel and applications thereof. Background Art

[0002] Antibacterial hydrogel is a biomedical material with a three-dimensional network structure and antibacterial properties. It can absorb and retain a large amount of water and has a good antibacterial effect. These characteristics make biomedical hydrogels have a wide range of application prospects in multiple fields such as tissue engineering, drug delivery, wound dressings and regenerative medicine. Antibacterial hydrogels are mainly composed of natural polymers (such as hyaluronic acid, collagen, chitosan, alginate, etc.) or synthetic polymers (such as polyacrylic acid, polyethylene glycol, etc.), and these polymer materials form a single network structure through physical or chemical crosslinking. However, due to the uneven crosslinked network structure, the single network structure is prone to stress concentration, and structural damage occurs at the weak crosslinking point, showing lower mechanical properties. Therefore, after multiple explorations, researchers have proposed to prepare a double network crosslinked hydrogel. Compared with the single network structure, the mechanical properties of the double network crosslinked structure have been greatly enhanced. However, with the progress of society, people's requirements for hydrogels have increased, and the double network crosslinked structure has gradually failed to meet the needs. At the same time, generally speaking, the high water content and excellent mechanical properties of hydrogels cannot be achieved at the same time. How to overcome its contradiction is one of the focuses of the present invention. How to naturally integrate its antibacterial effect into the hydrogel is the second focus of the present invention. Summary of the invention

[0003] Technical problem to be solved: The purpose of the present invention is to provide a multi-network antibacterial hydrogel and its application, which adopts a triple network interpenetrating structure composed of microporous silk fibers fixed with CuS nanozymes, gallic acid-grafted Echinops polysaccharide and carboxymethyl chitosan, wherein the gallic acid-grafted Echinops polysaccharide is covalently linked by phytic acid cross-linking, and the free amino groups on the carboxymethyl chitosan chain are covalently linked by phytic acid cross-linking, and double cross-linking is formed between the gallic acid-grafted Echinops polysaccharide and the carboxymethyl chitosan, making the structure more stable. The microporous silk fibers fixed with CuS nanozymes are fixed In the middle of the hydrogel, they are connected to each other, and connected to the gallic acid-grafted blue spinosa polysaccharide and carboxymethyl chitosan through covalent bonds or non-covalent interactions, forming multiple cross-links in the internal network of the hydrogel. These cross-linked composite structures are evenly distributed inside the hydrogel and can provide strong interactions. When subjected to external forces, they can act as "sacrificial bonds" to break and effectively dissipate energy, giving the hydrogel excellent mechanical properties. They have good inhibitory and killing effects on Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii and Fusarium sulphate.

[0004] Technical solution: A multi-network antibacterial hydrogel, wherein the hydrogel is a multi-network interpenetrating structure composed of microporous silk fibers immobilized with CuS nanozymes, gallic acid-grafted blue spinach polysaccharide and carboxymethyl chitosan. The preparation method of the above-mentioned multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: Disperse 2-5 parts of the microporous silk fibers immobilized with CuS nanozymes in 100 parts of a 1-2 wt.% aqueous solution of gallic acid grafted Echinops cyanobacteria polysaccharide, stir and then perform ultrasonic shearing; S2: adding 30 parts of 5wt.% carboxymethyl chitosan solution and stirring evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: soaking the composite aerogel in a phytic acid aqueous solution for 3-5 hours; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Furthermore, the preparation method of the microporous silk fiber immobilized with CuS nanozyme is as follows: S11: taking degummed silk, soaking it in a hydrochloric acid solution with a concentration of 20wt.% for swelling treatment for 5 minutes, and obtaining swollen silk; S12: freezing the swollen silk, and obtaining frozen silk; S13: soaking the frozen silk in ethanol for 8-10 hours at a freezing temperature to obtain a frozen body; S14: freeze-drying the frozen body to obtain microporous silk fibers; S15: soaking the microporous silk fiber in a dopamine hydrochloride solution with a concentration of 0.1-0.15 wt.%, stirring for 10 hours, to obtain a modified microporous silk fiber; S16: The modified microporous silk fiber is immersed in water, copper nitrate trihydrate and sodium sulfide nonahydrate are added and stirred for 2 hours, and the microporous silk fiber with CuS nanozyme fixed thereon is obtained after washing and drying. Furthermore, the degummed silk fiber has a diameter of 2-20 μm and a length of 50-300 μm. Furthermore, the dopamine hydrochloride solution in S15 is prepared by dissolving dopamine hydrochloride in a 0.01 M, pH 8.5 Tris-HCl buffer. Furthermore, the mass volume ratio of the modified microporous silk fiber, water, copper nitrate trihydrate and sodium sulfide nonahydrate in the S16 is: 10g:200mL:7g:7g. Furthermore, the ultrasonic shearing conditions in S1 are: ultrasonic frequency is 25-30kHz, power density is 0.4-0.6w / cm 2 , time is 1-2min. Furthermore, the concentration of the phytic acid aqueous solution in S4 is 10-20wt.%. Application of the above-mentioned multi-network antibacterial hydrogel in inhibiting or killing the activity of Acinetobacter baumannii and Fusarium sulphate. Application of the above multi-network antibacterial hydrogel in wound dressings for bacterially infected wounds. Beneficial effects: 1. The present invention adopts a triple network interpenetrating structure (including rigid covalent cross-linking and flexible non-covalent cross-linking network) composed of microporous silk fibers fixed with CuS nanozymes, gallic acid-grafted blue echinops polysaccharide and carboxymethyl chitosan. Gallic acid-grafted blue echinops polysaccharide is covalently linked by phytic acid cross-linking, and the free amino groups on the carboxymethyl chitosan chain are covalently linked by phytic acid cross-linking. Double cross-linking is formed between gallic acid-grafted blue echinops polysaccharide and carboxymethyl chitosan, making the structure more stable. The microporous silk fibers fixed with CuS nanozymes are fixed in the middle of the hydrogel, connected to each other, and connected to gallic acid-grafted blue echinops polysaccharide and carboxymethyl chitosan by covalent bonds or non-covalent interactions, forming multiple cross-linking of the internal network of the hydrogel. These cross-linked composite structures are evenly distributed inside the hydrogel, which can provide strong interactions. When subjected to external forces, they can act as "sacrificial bonds" to break to effectively dissipate energy, giving the hydrogel excellent mechanical properties. 2. The degummed silk fiber used in the hydrogel of the present invention has better mechanical properties than the conventionally used regenerated silk fibroin fiber. 3. The present invention prepares micropores on the degummed silk fibers, which can increase the specific surface area and the binding performance with other components on the one hand, and can also fix and disperse the CuS nanozyme on the other hand. 4. The present invention adopts gallic acid to graft Echinops edulis polysaccharide, which improves the stability and biological activity of Echinops edulis polysaccharide. The phenolic hydroxyl groups contained in the Echinops edulis polysaccharide can form hydrogen bonds with hydrogen atoms on the surface of carboxymethyl chitosan and silk fibers, thereby enhancing the interaction force between molecules, which is conducive to forming a stable cross-linked network of hydrogel. Moreover, since the Echinops edulis polysaccharide itself has antibacterial properties, it can also improve the antibacterial effect of the hydrogel itself. 5. The present invention adopts freeze-drying technology. During the freeze-drying process, the distance between the microporous silk fibers fixed with CuS nanozymes increases, reducing the interaction between them. The formation of ice crystals also exerts mechanical pressure on the surrounding silk fibers, so that the silk fibers are arranged into an orderly structure in the hydrogel, enhancing its mechanical properties. 6. While maintaining the mechanical properties of the hydrogel, the present invention adopts polysaccharide components containing polar functional groups such as hydroxyl, carboxyl, and amine groups, which can form hydrogen bonds with water molecules and enhance water retention capacity. At the same time, the triple network interpenetrating structure of the present invention provides a large amount of space to accommodate and fix water molecules and prevent rapid loss of water, thereby allowing the hydrogel to maintain a relatively high water content of more than 98.5%. 7. The present invention utilizes components that are loaded or grafted or have antibacterial effects themselves, and comprehensively coordinates their antibacterial effects, so that the antibacterial hydrogel has a good inhibitory and killing effect on Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii and Fusarium sulphate. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a photo of the appearance of the multi-network antibacterial hydrogel prepared in Example 9. DETAILED DESCRIPTION Example 1 The preparation method of the microporous silk fiber immobilized with CuS nanozyme is as follows: S11: taking degummed silk with a diameter of 2-20 μm and a length of 50-300 μm, and soaking it in a hydrochloric acid solution with a concentration of 20 wt.% for swelling treatment for 5 minutes to obtain swollen silk; S12: freezing the swollen silk at -20°C to obtain frozen silk; S13: soaking the frozen silk in ethanol for 8 hours at a freezing temperature to obtain a frozen body; S14: freeze-drying the frozen body to obtain microporous silk fibers; S15: dissolving dopamine hydrochloride in 0.01 M Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution having a concentration of 0.1 wt.%; S16: soaking the microporous silk fiber in a dopamine hydrochloride solution and stirring for 10 hours to obtain a modified microporous silk fiber; S16: 10 g of modified microporous silk fiber was immersed in 200 mL of water, 7 g of copper nitrate trihydrate and 7 g of sodium sulfide nonahydrate were added and stirred for 2 h, and microporous silk fiber with CuS nanozyme fixed thereon was obtained after washing and drying. Example 2 The preparation method of the microporous silk fiber immobilized with CuS nanozyme is as follows: S11: taking degummed silk with a diameter of 2-20 μm and a length of 50-300 μm, and soaking it in a hydrochloric acid solution with a concentration of 20 wt.% for swelling treatment for 5 minutes to obtain swollen silk; S12: freezing the swollen silk at -20°C to obtain frozen silk; S13: soaking the frozen silk in ethanol at a freezing temperature for 9 hours to obtain a frozen body; S14: freeze-drying the frozen body to obtain microporous silk fibers; S15: dissolving dopamine hydrochloride in 0.01 M Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution having a concentration of 0.13 wt.%; S16: soaking the microporous silk fiber in a dopamine hydrochloride solution and stirring for 10 hours to obtain a modified microporous silk fiber; S16: 10 g of modified microporous silk fiber was immersed in 200 mL of water, 7 g of copper nitrate trihydrate and 7 g of sodium sulfide nonahydrate were added and stirred for 2 h, and microporous silk fiber with CuS nanozyme fixed thereon was obtained after washing and drying. Example 3 The preparation method of the microporous silk fiber immobilized with CuS nanozyme is as follows: S11: taking degummed silk with a diameter of 2-20 μm and a length of 50-300 μm, and soaking it in a hydrochloric acid solution with a concentration of 20 wt.% for swelling treatment for 5 minutes to obtain swollen silk; S12: freezing the swollen silk at -20°C to obtain frozen silk; S13: soaking the frozen silk in ethanol for 10 hours at a freezing temperature to obtain a frozen body; S14: freeze-drying the frozen body to obtain microporous silk fibers; S15: dissolving dopamine hydrochloride in 0.01 M Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution having a concentration of 0.15 wt.%; S16: soaking the microporous silk fiber in a dopamine hydrochloride solution and stirring for 10 hours to obtain a modified microporous silk fiber; S16: 10 g of modified microporous silk fiber was immersed in 200 mL of water, 7 g of copper nitrate trihydrate and 7 g of sodium sulfide nonahydrate were added and stirred for 2 h, and microporous silk fiber with CuS nanozyme fixed thereon was obtained after washing and drying. The micropore diameter of the microporous silk fiber obtained in S14 of Example 1-3 and the antibacterial activity of the microporous silk fiber immobilized with CuS nanozyme (including Escherichia coli and Staphylococcus aureus) were measured: after activating the strain, the bacteria on the slant culture medium were picked up and cultured in liquid LB culture medium at 37°C in an air bath constant temperature oscillator for 12 h; the bacterial suspension was centrifuged, washed, and resuspended in a 0.85% NaCl solution, and its OD was adjusted to 600nm = between 0.095 and 0.105, that is, the bacterial cell concentration is 10 7 CFU / mL. For E. coli, take 2.5mL 107 CFU / mL bacterial suspension was added to 22.5mL 0.85% NaCl, and 0.3g of the microporous silk fiber immobilized with CuS nanozyme prepared in each example was added; for Staphylococcus aureus, 20mL 10 7 0.3 g of the microporous silk fiber immobilized with CuS nanozyme prepared in each example was added to the CFU / mL bacterial suspension, and the suspension was shaken and cultured at 37°C in an air bath constant temperature oscillator for 30 min. The bacterial suspension was diluted and spread on solid LB culture medium, and cultured at 37°C in an electric constant temperature incubator for 12 h, and the number of colonies was calculated. Table 1 Micropore size E. coli killing rate Staphylococcus aureus killing rate Example 1 0.08-5μm 66.5％ 85.7％ Example 2 0.1-6μm 67.6％ 86.5％ Example 3 0.15-8μm 68.3％ 87.9％ Example 4 The preparation method of gallic acid grafted Echinops polysaccharide is as follows: 2 g of gallic acid is dissolved in 100 mL of 0.5 mol / mL Tris-HCl buffer with a pH of 8.0, and then 2 g of Echinops polysaccharide is added, and the reaction is stirred for 12 hours. After the reaction is completed, anhydrous ethanol is added for alcohol precipitation for 24 hours, and the supernatant is discarded. The lower precipitate is washed 3 times with PBS and distilled water respectively, and vacuum freeze-dried to obtain gallic acid grafted Echinops polysaccharide. The grafting rate of gallic acid was calculated by measuring the absorbance at a wavelength of 260 nm using a UV-visible spectrophotometer. The grafting rate of gallic acid was 38.94%. Example 5 The preparation method of gallic acid grafted Echinops polysaccharide is as follows: 3g of gallic acid is dissolved in 100mL of 0.5mol / mL Tris-HCl buffer with a pH of 8.0, and then 2g of Echinops polysaccharide is added, and the reaction is stirred for 12h. After the reaction is completed, anhydrous ethanol is added for alcohol precipitation for 24h, and the supernatant is discarded. The lower precipitate is washed 3 times with PBS and distilled water respectively, and vacuum freeze-dried to obtain gallic acid grafted Echinops polysaccharide. The grafting rate of gallic acid was 41.19%. Example 6 The preparation method of gallic acid grafted Echinops polysaccharide is as follows: 4 g of gallic acid is dissolved in 100 mL of 0.5 mol / mL Tris-HCl buffer with a pH of 8.0, and then 2 g of Echinops polysaccharide is added, and the reaction is stirred for 12 hours. After the reaction is completed, anhydrous ethanol is added for alcohol precipitation for 24 hours, and the supernatant is discarded. The lower precipitate is washed 3 times with PBS and distilled water respectively, and vacuum freeze-dried to obtain gallic acid grafted Echinops polysaccharide. The grafting rate of gallic acid was 40.38%. After comprehensive comparison, the microporous silk fiber immobilized with CuS nanozyme prepared in Example 3 and the gallic acid-grafted Echinops cyanobacteria polysaccharide prepared in Example 5 were selected for subsequent experiments. Example 7 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 2 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Example 8 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 3 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Example 9 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Example 10 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Embodiment 11 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.0 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Example 12 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 2.0 wt.% gallic acid-grafted Echinops edulis polysaccharide aqueous solution, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Embodiment 13 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a 10 wt.% phytic acid aqueous solution for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Embodiment 14 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 15 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Embodiment 15 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 20 wt.% for 4 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Example 16 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 3 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Embodiment 17 The preparation method of the multi-network antibacterial hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 5 h; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel. Comparative Example 1 The difference between this comparative example and Example 9 is that the microporous silk fiber immobilized with CuS nanozyme is not used for reinforcement, specifically as follows: The preparation method of the hydrogel comprises the following steps, measured in parts by weight: S1: Take 100 mL of 1.5 wt.% gallic acid grafted Echinops cyanobacteria polysaccharide aqueous solution, add 30 mL of 5 wt.% carboxymethyl chitosan solution, and stir evenly; S2: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S3: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S4: Take out, place in a 45°C oven and continue the cross-linking reaction for 4 hours. Comparative Example 2 The difference between this comparative example and Example 9 is that gallic acid is not used to graft Echinops cyanobacteria polysaccharide, specifically as follows: The preparation method of the hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 130 mL of 5 wt.% carboxymethyl chitosan solution, stirred and ultrasonically sheared. The ultrasonic shearing conditions were: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S3: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S4: Take out, place in a 45°C oven and continue the cross-linking reaction for 4 hours. Comparative Example 3 The difference between this comparative example and Example 9 is that freeze drying is not performed, as follows: The preparation method of the hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of gallic acid grafted Echinops edulis polysaccharide, stirred and then ultrasonically sheared. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: adding 18 wt.% phytic acid aqueous solution, stirring, and cross-linking into a hydrogel; S4: Take out, place in a 45°C oven and continue the cross-linking reaction for 4 hours. Comparative Example 4 The difference between this comparative example and Example 9 is that Echinops cyanobacteria polysaccharide is directly used, specifically as follows: The preparation method of the hydrogel comprises the following steps, measured in parts by weight: S1: 4 g of microporous silk fibers immobilized with CuS nanozymes were dispersed in 100 mL of 1.5 wt.% aqueous solution of Echinops edulis polysaccharide, stirred and sheared by ultrasonic wave. The ultrasonic shearing conditions were as follows: ultrasonic frequency of 30 kHz and power density of 0.5 w / cm 2 , time is 2min; S2: Add 30 mL of 5 wt.% carboxymethyl chitosan solution and stir evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: immersing the composite aerogel in a phytic acid aqueous solution with a concentration of 18 wt.% for 4 h; S5: Take out, place in a 45°C oven and continue the cross-linking reaction for 4 hours. Performance Testing: Cytotoxicity assay: M293T cells were seeded in 96-well plates at a seeding density of 1×10 5 cells / well, cultured for 24 hours at 5% CO2 and 37°C with 200 μL of DMEM culture medium containing 10% fetal bovine serum. The hydrogel prepared in Example 9 was immersed in DMEM culture medium and soaked at 37°C for 12 hours to prepare gel extracts of 1, 10, 100, and 1000 μg / mL. After 24 hours, the culture medium in the 96-well plate was removed, 200 μL of gel extracts of different concentrations were added, and the culture was continued for 24 hours, and then 20 μL of MTT solution was added. After 4 hours of culture, the gel extract was removed, 150 μL of dimethyl sulfoxide was added, and the 96-well plate was shaken for 15 minutes, and the OD value was measured at 490 nm. A DMEM culture medium without gel was used as a blank group. Six replicate wells were set up for each group in parallel, and the average value was taken. Cell survival rate (%) = OD 490(样品) / OD 490(空白)×100% After culturing with gel extract (1, 10, 100, 1000 μg / mL) for 24 h, the survival rates of M293T cells were 92.2%, 95.3%, 98.9% and 99.5%, respectively. Various properties of the multi-network antibacterial hydrogel prepared in each example were tested, including mechanical properties, water content and antibacterial properties. The mechanical properties test was conducted on an electronic universal testing machine. The specific operation was as follows: the hydrogel was prepared into a dumbbell shape, the sample was fixed between the upper and lower clamps to ensure that it would not slip, and the sample was stretched at a speed of 50 mm / min. At the same time, the force and displacement at each moment would be recorded, and the tensile strength and elongation of the test hydrogel were calculated based on the initial cross-sectional area and initial length of the sample. In order to reduce errors, three samples were selected for each group for testing; Test of moisture content: Take a certain mass of the hydrogel sample in each example, place it in a forced air drying oven and heat it at 120° C. until the mass of the hydrogel no longer changes. The results are shown in Table 2 below: Table 2 Tensile stress (MPa) Young's modulus (MPa) Moisture content (%) Example 7 3.24 7.96 99.7 Example 8 3.55 8.19 99.8 Example 9 3.94 8.54 99.5 Example 10 4.13 8.71 98.7 Embodiment 11 3.80 8.26 99.2 Example 12 3.98 8.62 99.6 Embodiment 13 3.58 8.18 99.8 Embodiment 14 3.84 8.39 99.6 Embodiment 15 3.97 8.57 99.2 Example 16 3.85 8.50 99.6 Embodiment 17 3.94 8.55 99.5 Comparative Example 1 1.78 5.69 99.2 Comparative Example 2 3.60 8.17 93.1 Comparative Example 3 3.06 7.24 98.7 Comparative Example 4 3.83 8.43 99.2 Antibacterial experiment: Three common bacteria were selected: Staphylococcus aureus, Escherichia coli and Acinetobacter baumannii, and the antibacterial activity of the hydrogel prepared in each example was evaluated by plate counting method. 1.0 g of the hydrogel in each example was added to a 12-well plate, the bottom was flattened, and 3 mL of fresh LB liquid culture medium and 10 μL of diluted bacterial solution (1.5×10 6 CFU / mL), incubate in an incubator at 37°C for 24 hours, take out the 12-well plate, use a pipette to draw 10 μL of the co-culture solution onto the LB plate medium, spread it evenly with a glass rod, and incubate in an incubator at 37°C for 24 hours before counting the live bacteria. The antibacterial rate calculation formula is as follows: Where N0 is the number of colonies on the blank plate, and N1 is the number of colonies on the test plate. The antibacterial activity of the hydrogels of various examples against the fungus Fusarium sulwezi was determined by the growth rate method. The test results are shown in Table 3 below: Table 3 Antibacterial effect of hydrogels in various examples The above embodiments are intended to provide a clear and complete description of the technical solution, and are partial implementations of the present invention, rather than all implementations. However, the implementations of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations or simplifications that do not deviate from the spirit and principle of the present invention shall be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A multi-network antibacterial hydrogel, characterized in that: The hydrogel is a multi-network interpenetrating structure composed of microporous silk fibers fixed with CuS nanozymes, gallic acid-grafted Echinops cyanobacteria polysaccharide and carboxymethyl chitosan.

2. The method for preparing a multi-network antibacterial hydrogel according to claim 1, characterized in that: By weight, the method comprises the following steps: S1: Disperse 2-5 parts of the microporous silk fibers immobilized with CuS nanozymes in 100 parts of a 1-2 wt.% aqueous solution of gallic acid grafted Echinops cyanobacteria polysaccharide, stir and then perform ultrasonic shearing; S2: adding 30 parts of 5wt.% carboxymethyl chitosan solution and stirring evenly; S3: freeze in a dry ice / acetone bath for freeze drying to obtain a composite aerogel; S4: soaking the composite aerogel in a phytic acid aqueous solution for 3-5 hours; S5: Take out the gel and place it in a 45°C oven to continue the cross-linking reaction for 4 hours to obtain a multi-network antibacterial hydrogel.

3. The method for preparing a multi-network antibacterial hydrogel according to claim 2, characterized in that: The preparation method of the microporous silk fiber immobilized with CuS nanozyme is as follows: S11: taking degummed silk and soaking it in a hydrochloric acid solution with a concentration of 20 wt.% for swelling treatment for 5 minutes to obtain swollen silk; S12: freezing the swollen silk to obtain frozen silk; S13: soaking the frozen silk in ethanol for 8-10 hours at a freezing temperature to obtain a frozen body; S14: freeze-drying the frozen body to obtain microporous silk fibers; S15: soaking the microporous silk fiber in a dopamine hydrochloride solution with a concentration of 0.1-0.15 wt.%, stirring for 10 hours, to obtain a modified microporous silk fiber; S16: The modified microporous silk fiber is immersed in water, copper nitrate trihydrate and sodium sulfide nonahydrate are added and stirred for 2 hours, and the microporous silk fiber with CuS nanozyme fixed thereon is obtained after washing and drying.

4. The method for preparing a multi-network antibacterial hydrogel according to claim 3, characterized in that: The degummed silk fiber has a diameter of 2-20 μm and a length of 50-300 μm.

5. The method for preparing a multi-network antibacterial hydrogel according to claim 3, characterized in that: The mass volume ratio of the modified microporous silk fiber, water, copper nitrate trihydrate and sodium sulfide nonahydrate in the S16 is: 10g:200mL:7g:7g.

6. The method for preparing a multi-network antibacterial hydrogel according to claim 2, characterized in that: The ultrasonic shearing conditions in S1 are: ultrasonic frequency of 25-30kHz, power density of 0.4-0.6w / cm 2 , time is 1-2min.

7. The method for preparing a multi-network antibacterial hydrogel according to claim 2, characterized in that: The concentration of the phytic acid aqueous solution in S4 is 10-20 wt.%.

8. Use of the multi-network antibacterial hydrogel according to claim 1 or the multi-network antibacterial hydrogel prepared by the preparation method according to any one of claims 2 to 7 in inhibiting or killing the activity of Acinetobacter baumannii and Fusarium sullawesi.

9. Use of the multi-network antibacterial hydrogel according to claim 1 or the multi-network antibacterial hydrogel prepared by the preparation method according to any one of claims 2 to 7 in wound dressings for bacterially infected wounds.

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