CN115300666B

CN115300666B - Biological heuristic synergistic antibacterial hydrogel dressing and preparation method thereof

Info

Publication number: CN115300666B
Application number: CN202210933056.7A
Authority: CN
Inventors: 陈红霞; 王音典
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2022-04-29
Filing date: 2022-08-04
Publication date: 2024-04-12
Anticipated expiration: 2042-08-04
Also published as: CN115300666A

Abstract

The invention discloses a biological heuristic synergistic antibacterial hydrogel dressing and a preparation method thereof, comprising a DCS-OSA Schiff base crosslinked biocompatible hydrogel substrate, wherein OSA is connected with Cu-MOF and doped with rPDA NPs; the preparation method comprises the following steps: (1) preparing DCS, OSA, cu-MOF and rPDA NPs respectively; (2) synthesizing OSA and Cu-MOF into OSA-MOF; (3) Mixing OSA-MOF and DCS solution, adding rPDA NPs, and stirring to obtain DCS-OSAM-rPDA hydrogel.

Description

Biological heuristic synergistic antibacterial hydrogel dressing and preparation method thereof

Technical Field

The invention relates to a hydrogel wound dressing, in particular to a wound dressing which is inspired by biological behaviors and has a synergistic antibacterial effect and a preparation method thereof.

Background

In recent years, the frequent occurrence of skin wounds in human life has led to wound therapy becoming an important health problem, often consuming high economic and social costs. Wound healing is a complex, dynamic biological process involving the synergistic action of multiple tissue cells, involving four distinct and overlapping stages of hemostasis, inflammation, proliferation and remodeling. Hemostasis is the first important problem faced in the early stages of wound healing; bacterial infection can then lead to severe tissue damage and worsening wound healing; neutrophils and macrophages accumulate at the wound site and produce large amounts of Reactive Oxygen Species (ROS), which affect the migration of fibroblasts to the wound and the formation of granulation tissue during the proliferation and remodeling stages of wound healing. In response to the above challenges, a variety of biomaterials have been developed for wound healing, including electrospun fibers, polymeric films, porous foams, and hydrogels. Hydrogels are three-dimensional (3D) networks composed of physical or chemical bond crosslinks of hydrophilic polymers such as chitosan, polyethylene glycol, and the like, insoluble hydrophilic structures show significant potential for absorbing wound exudates, can provide a moist environment to the wound and allow oxygen diffusion to accelerate healing. Although the use of hydrogel wound dressings has promoted wound healing to some extent, its application addresses only a single problem in wound healing as described above, failing to produce a synergistic effect throughout the wound healing process, which greatly affects the final effect of highly coordinated wound healing at each stage. Furthermore, most of these hydrogels can only repair a single type of wound, which limits their wide clinical application. Therefore, there is a need to develop a novel hydrogel wound dressing with multiple functions of hemostasis, anti-infection, antioxidation and the like, which can play a synergistic effect in the whole healing process of different wounds, and is used for promoting the healing of the wounds in the whole process.

Tissue deterioration caused by bacterial infection is the most troublesome problem faced during wound treatment, and thus antibacterial is undoubtedly the most critical and focused part of the wound healing process. Antibiotics are a common method of combating bacterial infections, but the use of antibiotics has a number of drawbacks. Thus, there is an urgent need to develop safe, efficient, environmentally friendly antibiotic-free therapies. The condition triggering antibacterial strategy and the active antibacterial strategy can well avoid the safety problem, and great interest is brought to people. Common condition-triggered antibacterial strategies mainly include photothermal therapy (PTT) and photodynamic therapy (PDT), but both are highly dependent on the synthesis of photo-activated nanomaterials and the additional conditions of specific wavelength light sources, which are complex to operate and difficult to control in practical applications. The active antibacterial strategy can spontaneously and directly contact or indirectly release small molecular substances to destroy the outer membrane of bacteria so as to kill the bacteria, and in practical application, the antibacterial effect is not strong but complex external conditions are not needed. In order to solve the performance defect of a certain single antibacterial agent, a novel organic/inorganic composite antibacterial material which has high efficiency, long curative effect, small environmental pollution, good biocompatibility and difficult drug resistance generation is developed, and has great potential in practical anti-infection applications such as wound healing and the like.

The Metal Organic Framework (MOF) is a coordination porous material composed of metal ions or a multidentate organic ligand, has the characteristics of ultrahigh specific surface area, adjustable and uniform pore structure, good thermal stability and the like, and has wide application in biomedical fields such as drug delivery, biosensing, biological imaging and the like. Interestingly, the MOF is a novel inorganic/organic porous composite material formed by compounding metal ions-inorganic materials and organic ligands-organic materials, has the high efficiency of an organic antibacterial agent and the stability of the inorganic antibacterial agent, can greatly improve antibacterial performance and application range through synergistic effect, has the advantages of high heat resistance, good safety, high antibacterial efficiency, quick antibacterial effect, good antibacterial persistence, good stability, difficulty in generating drug resistance and the like, and is very suitable for medical antibacterial. HKUST-1 destroys Cu of bacterial cell membrane by releasing ²⁺ Has remarkable antibacterial activity against Staphylococcus aureus and Escherichia coli. Recently, a new method for post-synthesis modification of IRMOF-3-based organic ligands is reported to introduce antibacterial functions, so that antibacterial performance of various bacteria such as escherichia coli, staphylococcus aureus and the like is improved, and the antibacterial effect is superior to that of commercial antibiotics. The antibacterial mechanism of the MOF mainly relies on free movement after the release of antibacterial components in a solution environment, so that the MOF contacts bacteria for killing. However, the wound environment has complex and variable characteristics, the wound dressing needs to destroy bacteria in different environments such as a solid skin layer, liquid secretion, external air and the like, the service life of antibacterial substances such as Reactive Oxygen Species (ROS) is short, the diffusion distance is limited, and the movement of the bacteria is interfered, so that the contact efficiency between the bacteria and the antibacterial substances is obviously reduced, the antibacterial effect of the MOF is greatly weakened, and the wound infection treatment effect is not ideal. Thus, the bacterial capture capacity and bactericidal efficiency of MOFs alone are still insufficient for clinical applications in the wound environment to combat infections and promote wound healing.

The process of natural selection results in the evolution of molecular structures as small as large as biological behavior, and these materials, structures, models, systems and processes have been optimized for a wide variety of specific functions. Bionics and biological heuristics based on natural design principles are used to design and build various highly complex and precise engineering models, and to solve problems and challenges faced by humans with rich scientific knowledge. Spiders are an excellent hunter and stand long on top of the insect food chain. The hunting process is roughly divided into three steps: firstly, fixing the hunting object through a spider web, then biting the outer skin of the hunting object through the bucktooth, and finally releasing venom in the hunting object to perform overall process synergistic killing on the hunting object. Inspired by the biological behavior of spiders to capture prey, functional nanoparticles such as MOFs encapsulated in hydrogels resemble inflexible but lethal "spiders", whereas hydrogel networks can be designed as "spider webs" with the function of anchoring, capturing bacteria. Therefore, cu-MOF and rPDA NPs are introduced into the hydrogel as functional components, and the multifunctional nanoparticle-hydrogel composite wound dressing with high efficiency and synergistic antibacterial performance is designed by integrating the functions of 'cobweb capturing prey', 'bucktooth damaging outer membrane', 'venom internal killing', and the like, has multiple functions of hemostasis, anti-infection, antioxidation, and the like, and is used for promoting wound healing in the whole process.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the technical problems to be solved by the present invention include:

1. the single type of antimicrobial agent has weaker properties.

2. The bacterial capture capacity and bactericidal efficiency of MOFs alone are still insufficient for clinical applications in the wound environment to combat infections and promote wound healing.

3. Single function hydrogels fail to produce a synergistic promotion throughout wound healing.

To achieve the above object, the present invention provides a bio-inspired synergistic antibacterial hydrogel dressing, comprising DCS-OSA schiff base cross-linked biocompatible hydrogel substrate, wherein OSA is attached to Cu-MOF and incorporated into rPDA NPs.

The invention also provides a preparation method of the biological heuristic synergistic antibacterial hydrogel dressing, which comprises the following steps:

(1) DCS, OSA, cu-MOF and rPDA NPs are prepared respectively;

(2) Synthesizing OSA and Cu-MOF into OSA-MOF;

(3) Mixing OSA-MOF and DCS solution, adding rPDA NPs, and stirring to obtain DCS-OSAM-rPDA hydrogel.

Further, in step (1), DCS is prepared by: dissolving chitosan in acetic acid water solution, and stirring at room temperature; in order to make the reaction more uniform, adding dodecanal into ethanol, then adding the solution into chitosan solution, and stirring until the solution is dissolved; then adding excessive sodium borohydride into chitosan solution slowly, continuously stirring at room temperature for reaction, adjusting pH to be neutral by using sodium hydroxide solution, and precipitating DCS by using ethanol; washing the precipitate with 70% -100% ethanol until the pH value is neutral; the product was dried under vacuum to constant weight and finally the resulting solid was ground to give a white fine powder.

Further, in step (1), OSA is prepared by: sodium alginate is dissolved in ultrapure water to prepare 1% sodium alginate aqueous solution, naIO4 is added into the sodium alginate solution, and after stirring reaction at room temperature and in the dark, ethylene glycol is added into the reaction solution to quench oxidation; after the reaction is finished, dialyzing the solution in ultrapure water by using a dialysis membrane, and changing water for a plurality of times until the dialysate does not contain NaIO4; and freeze-drying the dialyzate to obtain OSA.

Further, in step (1), the Cu-MOF is prepared by: cu (NO) ₃ ) ₂ ·2.5H ₂ O and 3-amino-5-mercapto-1, 2, 4-triazole (ATMA) were dissolved in DMF/C ₂ H ₅ Heating the mixed solution in OH mixed solvent for reaction, taking out the reaction solution after the reaction is finished, washing the reaction solution, and redissolving the precipitate in DMF/C ₂ H ₅ And (3) in the OH mixed solvent, continuously reacting under vacuum, and then washing again to obtain the final product Cu-MOF.

Further, in step (1), rPDA NPs are prepared by: first, polydopamine nanoparticles were synthesized: dissolving dopamine hydrochloride in a mixed solution of ultrapure water and ethanol, and then dropwise adding ammonia water into a solution system; after the reaction liquid is continuously stirred and reacted, washing the solution with ultrapure water to obtain PDA nano particles; and then, mixing the prepared PDA with ascorbic acid for reaction, and washing to ensure that unreacted ascorbic acid is no longer present in the system, thereby obtaining the reduced polydopamine nano-particles.

Further, in step (2), the OSA-MOF is prepared by: firstly, adding MES buffer solution with pH value of 4.5-6 into two containers, then respectively adding EDC and NHS, adding the two solutions into OSA, and after the reaction of activating carboxyl is finished, adding Cu-MOF into the solution for continuous reaction; finally, the reaction product is washed to give OSAM.

Further, in the step (3), 25% w/v OSAM and 1.5% w/v DCS solution are mixed, rPDA NPs with a certain concentration are added, and then the mixture is stirred at room temperature to change the solution from a liquid state to a gel state, and finally the DCS-OSAM-rPDA hydrogel is obtained.

The invention has the technical effects that:

1. the biological elicitation synergistic antibacterial hydrogel integrates multiple functions of 'a spider web capturing prey', 'a bucktooth damaging an outer membrane', 'killing inside venom', and the like, and the biological elicitation synergistic antibacterial mechanism of the biological elicitation synergistic antibacterial hydrogel is deeply studied. The hydrogel has excellent antibacterial effect, and has an antibacterial rate of more than 99.9% for staphylococcus aureus and escherichia coli.

2. By introducing functional materials into a hydrogel system, the composite hydrogel achieves initial hemostasis, mid-term anti-infection, anti-inflammation, later-stage anti-oxidation and healing promotion in the whole process of wound healing, a novel hydrogel wound dressing integrating multiple functions of hemostasis, anti-infection, anti-oxidation and the like is developed, the synergistic effect can be exerted in the whole healing process of different wounds, the limitation of single-function hydrogel in the wound healing promotion process is solved, and therefore the composite hydrogel is used for promoting wound healing in the whole process and has potential value for clinical application of wound healing. After establishing a full-thickness skin injury model of the infected rat, performing entity evaluation, wherein the wound closure rate is as high as 90% after the composite hydrogel is treated for 10 days.

3. The hydrogel material has wide sources, low cost and simple preparation process, and is a novel antibacterial hydrogel dressing with clinical transformation prospect.

The conception, specific structure, and technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, features, and effects of the present invention.

Drawings

FIG. 1 is a schematic illustration of a bioaugmentation synergistic antimicrobial hydrogel macroscopic synthesis process and self-healing performance verification in a preferred embodiment of the present invention;

FIG. 2 is a schematic representation of a characterization experiment of functional nanoparticle and hydrogel synthesis in a preferred embodiment of the present invention;

FIG. 3 is a schematic illustration of in vitro antimicrobial performance verification of a bio-inspired synergistic antimicrobial hydrogel in accordance with a preferred embodiment of the present invention.

Detailed Description

The following description of the preferred embodiments of the present invention refers to the accompanying drawings, which make the technical contents thereof more clear and easy to understand. The present invention may be embodied in many different forms of embodiments and the scope of the present invention is not limited to only the embodiments described herein.

As shown in fig. 1-2, in this embodiment, a schiff base cross-linking of DCS (dodecyl chitosan) -OSA (oxidized sodium alginate) is used as a biocompatible hydrogel substrate, cu-MOF (copper-based metal organic framework) is connected and rPDA NPs (reduced polydopamine nanoparticles) are doped, and a hydrogel dressing with bionic synergistic antibacterial function is prepared through a simple reaction and can be used for promoting wound healing in the whole process. The specific preparation and verification steps are as follows:

(1) Synthesis of functional nanoparticles:

synthesis of Cu-MOF: cu (NO) ₃ ) ₂ ·2.5H ₂ O (3 mmol) and 3-amino-5-mercapto-1, 2, 4-triazole (ATMA) (4.5 mmol) were dissolved in 100mL DMF/C ₂ H ₅ Mixed solvent in OH (DMF: C) ₂ H ₅ Oh=1:1), the mixed solution was heated to 120 ℃, and the reaction was continued for 12h. After the completion of the reaction, the reaction mixture was taken out and washed at 8000 rpm. After washing, the precipitate was redissolved in DMF/C ₂ H ₅ OH Mixed solvent (DMF: C) ₂ H ₅ Oh=1:1), vacuum at 120 deg.cAnd continuing the reaction for 24 hours, and washing again after the reaction to obtain the final product Cu-MOF.

Synthesis of rPDA NPs: first, polydopamine (PDA) nanoparticles were synthesized: 400mg of dopamine hydrochloride was dissolved in a mixed solution of 90mL of ultrapure water and 30mL of ethanol, and then 1.5mL of aqueous ammonia was rapidly added dropwise to the solution system. The reaction solution was stirred continuously for 24 hours, and the solution was observed to change from transparent to yellow and finally to dark brown. After the reaction was completed, the solution was washed twice with ultrapure water and centrifuged at 15000rpm for 10 minutes each time to obtain PDA nanoparticles. Next, PDA was reduced by ascorbic acid to produce reduced polydopamine nanoparticles (rPDA NPs): the prepared PDA was mixed with an appropriate amount of ascorbic acid (300 mM) for 30 minutes. After the reaction, the solution was washed at least 3 times to ensure that unreacted ascorbic acid was no longer present in the system.

(2) Preparation of a biological heuristic synergistic antibacterial hydrogel dressing:

synthesis of dodecyl modified chitosan (DCS): 1g of Chitosan (CS) was dissolved in 50mL of 2% aqueous acetic acid and stirred at room temperature. To make the reaction more uniform, a certain amount of dodecanal was added to 40mL of ethanol, and then this solution was added to the above chitosan solution, and stirred for 4 hours until dissolved. Excess sodium borohydride cyanide (NaCNBH) ₄ Cs=3:1) was slowly added to the solution system and stirred continuously at room temperature for 14h. After the reaction, the pH was adjusted to 7.0 with sodium hydroxide solution and DCS was precipitated with ethanol. Washing the precipitate with 70% -100% ethanol for more than 4 times until the pH value is neutral. The product was dried under vacuum at 40 ℃ to constant weight and finally the resulting solid was ground to give a white fine powder.

Synthesis of Oxidized Sodium Alginate (OSA): 1g sodium alginate is dissolved in 100mL ultra-pure water to prepare 1% sodium alginate aqueous solution, and then 8g NaIO is added into the sodium alginate solution ₄ Stir overnight at room temperature in the dark. After 24 hours of reaction, oxidation was quenched by adding 2mL of ethylene glycol to the reaction solution with stirring for 0.5 hour. After the reaction was completed, the solution was dialyzed against ultrapure water (5L) with a dialysis membrane (MWCO-3500 Da) and water was changed several times until the dialysate contained no sodium periodate. By adding 0.5mL of dialysate aliquot to 0.5mL of 1% AgNO ₃ In solutionAnd ensure that there is no precipitate to check NaIO ₄ Is present. After dialysis for 72 hours, the dialysate was freeze-dried to obtain OSA.

Synthesis of oxidized sodium alginate-MOF (OSAM): carboxyl groups are activated by EDC and NHS, allowing OSA and Cu-MOF to be linked by amide bond formation. First, 250. Mu.L of MES buffer (pH 4.5-6) was added to two test tubes, then 4mg of EDC and 6mg of NHS were added, respectively, 200. Mu.L of each of the two solutions was added to 100mg of OSA, and the reaction for activating carboxyl groups was continued for 30 minutes. After the reaction was completed, 10. Mu.L of Cu-MOF (2.5 mg/mL) was added to the solution, and the reaction was continued for 2 hours. Finally, the reaction product is washed to give OSAM.

Synthesis of hydrogels: to synthesize DCS-OSAM-rPDA hydrogel, 25% w/v OSAM, 1.5% w/v DCS solution was mixed, 3.5-140. Mu.g/mL rPDA NPs were added, and then stirred at room temperature for 15 minutes. The solution was observed to change from liquid to gel, and finally a DCS-OSAM-rPDA hydrogel was obtained. The hydrogel was freeze-dried at-80℃for 24 hours. The freeze-dried hydrogel sample is stuck on a conductive adhesive tape on a sample plate, and metal spraying (spraying time is 100 s) is performed, so that the dry hydrogel is conductive. Then, the test was performed by photographing with a scanning electron microscope. Hydrogels and their components were characterized by FT-IR to verify the success of the synthesis reaction.

(3) Verification of the synergistic antibacterial properties of the biostimulation synergistic antibacterial hydrogel:

as shown in FIG. 3, the antibacterial performance of the material was studied using a representative strain of gram-negative bacteria, escherichia coli and a representative strain of gram-positive bacteria, staphylococcus aureus, as model bacteria. According to national standard GB/T20944.3-2008 of the people's republic of China, an oscillation method is adopted for the antibacterial performance test. Adding 2mL of the primary inoculum suspension into 9mL of nutrient broth, and uniformly mixing; mixing 1mL of the bacterial liquid into 9mL of nutrient broth; 1mL was mixed in 9mL PBS buffer; 5mL was mixed into 45mL PBS buffer solution to successfully prepare 10 ⁴ CFU/mL bacterial suspension, 70mL PBS buffer was added to the Erlenmeyer flask, sample and control were added, and 5mL bacterial suspension was added, and the culture was shaken at 37℃and 130r/min for 18h. After shaking, 100. Mu.L of the bacterial liquid was removed from the flask and spread on nutrient agar medium. Culturing at 37deg.C for 24 hrAfter that, the colony count on each plate was calculated. The number of colonies obtained in the negative control was N _C The number of colonies obtained in the sample was N _S The antibacterial ratio (R,%) is calculated as follows: r= (NC-NS)/nc×100%. The antimicrobial properties of hydrogels and their components were verified using the zone of inhibition (ZOI) method according to the standard: 100. Mu.L of the above bacteria were dropped on an agar plate and uniformly smeared. The hydrogel and its components were added thereto and incubated at 37℃for 18 hours, and finally the size of ZOI was observed. The initial bacterial solution and the antimicrobial material solution were mixed overnight at a volume ratio of 1:1 by setting the concentration of Cu-MOF to 2.5, 5, 10, 25, 50. Mu.g/mL, and 100. Mu.L of the bacterial solution was added dropwise to the agar plate for even application, and the Minimum Inhibitory Concentration (MIC) was calculated according to standard methods. The two bacteria are sampled before and after the antibacterial material treatment, glutaraldehyde is fixed, and alcohol gradient dehydration is performed. The bacterial morphology was observed with a scanning electron microscope.

(4) Demonstration of wound healing performance by the biological elicitation in combination with the antibacterial hydrogel overall process:

mice tail-breaking hemostasis experiment: the mice were anesthetized with 4% chloral hydrate by intraperitoneal injection. After anesthesia, mice were placed on an experimental bench and the tail was sterilized. Half of the tail was cut off and free bleeding was allowed for 10s. After 10s, exuded blood was wiped off, the tail was inserted into gauze and hydrogel for hemostatic treatment, and the same wound was established without external intervention in the mouse negative control group. The hemostatic material was removed every 10 seconds and bleeding was observed to continue. When the wound is hemostatic, the time from wound treatment to wound hemostasis is recorded. In the experiment for detecting the blood loss, the mass m of the hemostatic material is weighed before treatment ₀ Weigh mass m of material after experiment is completed ₁ . The calculation formula of the blood loss is as follows: blood loss = m ₁ -m ₀ 。

And verifying the protective effect on oxidative stress injured cells: to verify the oxidative stress protection of rPDA NPs on cells, the treatment of hydrogels with H was measured ₂ O ₂ Cell viability of cultured 293T. 293T cells were first seeded in 6-well plates and cultured overnight. The cell culture medium was removed and the adherent cells were then incubated with the hydrogel for 24 hours at 37 ℃. Removing excess hydrogel, mixing the cells with H ₂ O ₂ Incubate at 37℃for 24 hours and assess cell viability by CCK-8 kit.

Cytotoxicity test: 293T cells were cultured in 96-well cell culture dishes for 24 hours with 4000 cells per well (100. Mu.L per well) to attach prior to the experiment. Then, different materials were added to the wells and incubated for an additional 24 hours. The CCK-8 kit was used to determine the cell viability of the experimental group and is expressed as a percentage of cell viability relative to control cells.

Wound healing in vivo experiments: SD male mice (average body weight 180 g) were anesthetized by intraperitoneal injection of 4% chloral hydrate (0.1 ml/10 g) and shaved with an electric hair clipper. A full layer skin defect wound (circular, 1 cm diameter) was then cut into the back of each mouse. Thereafter, 100. Mu.L of 10 ⁸ CFU/mL staphylococcus aureus infects wounds for 24 hours, forming infectious wounds. After washing with physiological saline, the experimental group was treated with the hydrogel sample, and the control group was treated with only physiological saline. Taking photos of different groups at fixed heights by using cameras at 0d, 1d, 2d, 4d, 6d, 8d, 9d and 10d after operation, recording the size (A) and images of the wound surface, and calculating the wound closure rate (%) by a formula: wound healing rate (%) = (a) ₀ –A _T )/A ₀ ×100％。

The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention without requiring creative effort by one of ordinary skill in the art. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.

Claims

1. The preparation method of the biological heuristic synergistic antibacterial hydrogel dressing is characterized by comprising the following steps:

(1) Preparing Dodecyl Chitosan (DCS), oxidized Sodium Alginate (OSA), cu-MOF and rPDA NPs respectively;

(2) Synthesizing Oxidized Sodium Alginate (OSA) and Cu-MOF into Cu-OSA-MOF;

(3) Mixing Cu-OSA-MOF and Dodecyl Chitosan (DCS) solution, adding rPDANPs, and stirring to obtain DCS-OSAM-rPDA hydrogel.

2. The method for preparing a bio-inspired synergistic antimicrobial hydrogel dressing of claim 1, wherein in step (1), dodecyl Chitosan (DCS) is prepared by: dissolving chitosan in acetic acid water solution, and stirring at room temperature; in order to make the reaction more uniform, adding dodecanal into ethanol, then adding the solution into chitosan solution, and stirring until the solution is dissolved; then adding excessive sodium borohydride into chitosan solution slowly, continuously stirring at room temperature for reaction, adjusting pH to be neutral by sodium hydroxide solution, and precipitating Dodecyl Chitosan (DCS) by ethanol; washing the precipitate with 70% -100% ethanol until the pH value is neutral; the product was dried under vacuum to constant weight and finally the resulting solid was ground to give a white fine powder.

3. The method for preparing a bio-inspired synergistic antimicrobial hydrogel dressing of claim 1, wherein in step (1), oxidized Sodium Alginate (OSA) is prepared by: dissolving sodium alginate in ultrapure water to prepare 1% sodium alginate water solution, and adding NaIO into the sodium alginate solution ₄ After the reaction is stirred at room temperature and protected from light, the oxidation is quenched by adding glycol into the reaction solution under stirring; after the reaction, the solution was dialyzed against ultrapure water using a dialysis membrane, and water was changed a plurality of times until no NaIO was contained in the dialysate ₄ The method comprises the steps of carrying out a first treatment on the surface of the Freeze-drying the dialysate to obtain Oxidized Sodium Alginate (OSA).

4. The method of preparing a bio-inspired synergistic antimicrobial hydrogel dressing of claim 1, wherein in step (1), cu-MOF is prepared by: cu (NO) ₃ ) ₂ ·2.5H ₂ O and 3-amino-5-mercapto-1, 2, 4-triazole (ATMA) were dissolved in DMF/C ₂ H ₅ Heating the mixed solution in OH mixed solvent for reaction, taking out the reaction solution after the reaction is finished, washing the reaction solution, and redissolving the precipitate in DMF/C ₂ H ₅ And (3) in the OH mixed solvent, continuously reacting under vacuum, and then washing again to obtain the final product Cu-MOF.

5. The method of preparing a bio-inspired synergistic antimicrobial hydrogel dressing of claim 1, wherein in step (1), rpranps are prepared by: first, polydopamine nanoparticles were synthesized: dissolving dopamine hydrochloride in a mixed solution of ultrapure water and ethanol, and then dropwise adding ammonia water into a solution system; after the reaction liquid is continuously stirred and reacted, washing the solution with ultrapure water to obtain PDA nano particles; and then, mixing the prepared PDA with ascorbic acid for reaction, and washing to ensure that unreacted ascorbic acid is no longer present in the system, thereby obtaining the reduced polydopamine nano-particles.

6. The method of preparing a bio-inspired synergistic antimicrobial hydrogel dressing of claim 1, wherein in step (2), cu-OSA-MOF is prepared by: firstly, MES buffer solution with pH value of 4.5-6 is added into two containers, EDC and NHS are respectively added, the two solutions are added into Oxidized Sodium Alginate (OSA), and after the reaction of activating carboxyl is finished, cu-MOF is added into the solution for continuous reaction; finally, the reaction product is washed to give Cu-OSA-MOF.

7. The method for preparing a bio-heuristic synergic antibacterial hydrogel dressing according to claim 1, wherein in step (3), 25% w/v Cu-OSA-MOF and 1.5% w/v Dodecyl Chitosan (DCS) solution are mixed, 3.5-140 μg/mL of rpsan ps is added, and then stirred at room temperature to change the solution from liquid state to gel state, thereby obtaining DCS-OSAM-rPDA hydrogel.