An exosome-integrated antibacterial polymer material and its preparation method

Abstract

The present application provides an exosome-integrated antimicrobial polymer material and its preparation method, belonging to the field of intelligent biomimetic materials. The method comprises: introducing a benzimide bond into the molecular structure of a polylysine-chitosan copolymer to obtain a first copolymer; covalently coupling D-glutamic acid and electrostatically adsorbing a lipoteichoic acid-binding peptide to obtain a second copolymer; mixing a phosphate buffer solution of aldehyded methylcellulose and a phosphate buffer solution of amino-modified chitosan to obtain a first mixture; adding a mixture of protocatechualdehyde and FeCl3 solution to the first mixture to obtain a second mixture; and adding the second copolymer, placental mesenchymal stem cell exosomes, and Ag@rGO nanoparticles to the second mixture under stirring, and allowing the mixture to stand to obtain the exosome-integrated antimicrobial polymer material. This method simultaneously improves the antimicrobial, repair, mechanical, and environmental responsiveness of the exosome-integrated antimicrobial polymer material.

Description

Technical Field

[0001] The present application relates to the technical field of intelligent biomimetic materials, and in particular to an exosome-integrated antibacterial polymer material and a preparation method thereof. Background Art

[0002] In the field of skin wound repair, especially in the treatment of chronic infected wounds (such as diabetic foot ulcers and burn infections), traditional antibacterial materials such as silver dressings and antibiotic-loaded hydrogels face multiple challenges such as enhanced drug resistance, risk of tissue damage, limited therapeutic effects, and poor material adaptability.

[0003] Exosomes are nanoscale vesicles secreted by cells that contain a variety of bioactive molecules, including proteins and nucleic acids. In recent years, the potential application of exosomes in wound repair has gradually attracted attention. Exosomes can promote repair processes such as angiogenesis and epithelialization, while also modulating inflammatory responses. Furthermore, self-healing polymer hydrogels are intelligent materials with the ability to self-repair, capable of self-restoring to their original strength and functionality when cracks appear within and on their surfaces. This self-healing ability is achieved through the cleavage and reconnection of reversible covalent and reversible non-covalent bonds. Self-healing hydrogels have broad application prospects in biosensors, wound dressings, shape memory materials, and biomedical carriers. Therefore, combining self-healing polymer hydrogels with exosomes could provide new approaches for the treatment of chronic infected wounds.

[0004] Chinese patent CN 109912850 B discloses a self-healing hydrogel containing exosomes, its preparation method, and its application. Due to the antibacterial properties of the gel and the sustained release of exosomes within the gel, the exosome-containing self-healing hydrogel of the present invention exhibits good biocompatibility, good self-healing performance, and degradation rate. However, when directly loaded onto traditional hydrogels, exosomes are easily inactivated by physical extrusion or oxidative stress, and lack a targeted delivery mechanism, resulting in low repair efficiency. Chinese patent CN 108904875 B discloses an antibacterial self-healing hydrogel excipient for promoting the healing of chronic wounds, its preparation method, and its application. Exosomes are loaded onto a cationic polymer through electrostatic interaction and then encapsulated within a hydrogel with a double-network structure, thereby obtaining an antibacterial self-healing hydrogel excipient for promoting the healing of chronic wounds. However, this exosome-containing hydrogel relies on the positive charge of cationic polymers (such as ε-polylysine and polyethyleneimine) for bactericidal purposes, destroying bacterial membranes solely through electrostatic interaction. Furthermore, exosomes are easily inactivated by charge instability or physical extrusion. Therefore, how to effectively protect and deliver exosomes, achieve their synergistic effect with antibacterial materials, and at the same time improve the antibacterial, repair, mechanical properties and environmental responsiveness of exosome-integrated antibacterial polymer materials has become a hot topic and difficulty in current research. Summary of the Invention

[0005] The present application provides an exosome-integrated antibacterial polymer material and a preparation method thereof to solve the following technical problem: how to simultaneously improve the antibacterial, repair, mechanical properties and environmental responsiveness of the exosome-integrated antibacterial polymer material.

[0006] In a first aspect, the present application provides a method for preparing an exosome-integrated antibacterial polymer material, the method comprising:

[0007] introducing a benzimide bond into the molecular structure of a polylysine-chitosan copolymer to obtain a first copolymer;

[0008] Modifying the first copolymer with a bacteria-targeting ligand by covalently coupling D-glutamic acid and an electrostatically adsorbed lipoteichoic acid binding peptide to obtain a second copolymer;

[0009] Mixing the phosphate buffer solution of aldehyde-modified methylcellulose and the phosphate buffer solution of amino-modified chitosan to obtain a first mixture;

[0010] adding a mixture of protocatechuic aldehyde and FeCl3 solution to the first mixture and adjusting the pH to 6.0-7.0 to obtain a second mixture;

[0011] Under stirring, the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles are added to the second mixture, and the mixture is allowed to stand to obtain the exosome-integrated antibacterial polymer material.

[0012] Optionally, the method of introducing a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer comprises:

[0013] The phosphate buffer solution of polylysine and the phosphate buffer solution of chitosan are mixed in a molar ratio of 1:1, a mixed cross-linking agent of EDC and NHS is added, and the mixture is reacted at 25-30° C. for 10-12 hours, and then purified to obtain a polylysine-chitosan copolymer;

[0014] The polylysine-chitosan copolymer is dissolved in a DMF solvent, and p-formylbenzoic acid is added. The mixture is stirred and reacted at 60-70° C. under argon protection for 20-28 hours, and then purified to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer.

[0015] Optionally, the molar ratio of EDC to NHS is 1:(0.8-1.2);

[0016] The mass of the p-formylbenzoic acid is 5% to 10% of the mass of the polylysine-chitosan copolymer.

[0017] Optionally, the first copolymer is modified with a bacteria-targeting ligand by covalently coupling D-glutamic acid and an electrostatically adsorbed lipoteichoic acid binding peptide to obtain a second copolymer, comprising:

[0018] Mixing a phosphate buffer of D-glutamic acid with a mixed crosslinker of EDC and NHS to activate the carboxyl group, then mixing with the first copolymer and reacting at 20-30° C. for 4-8 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purifying to obtain a D-Glu modified copolymer;

[0019] An aqueous solution of lipoteichoic acid binding peptide with a concentration of 0.5 to 2 mg / mL is mixed with a D-Glu modified copolymer and stirred for 2 to 6 hours at a pH of 5.5 to 6.5 to adsorb the lipoteichoic acid binding peptide to the surface of the D-Glu modified copolymer through electrostatic interaction. The mixture is then purified and freeze-dried to obtain a second copolymer.

[0020] Optionally, the molar ratio of EDC to NHS is 1:(0.8-1.2);

[0021] The molar ratio of the D-glutamic acid to the first copolymer is 1:(1.5-2);

[0022] The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:(8-12).

[0023] Optionally, the concentration of the phosphate buffer of the aldehyded methylcellulose is 8-12 wt %, the concentration of the phosphate buffer of the amino-chitosan is 2-4 wt %, and the mixing volume ratio is 1:(0.8-1.2).

[0024] Optionally, the molar ratio of protocatechuic aldehyde to FeCl3 is (3-4):1, and the Fe in the second mixture 3+ The final concentration is 0.08~0.12M.

[0025] Optionally, the Ag@rGO nanoparticles are synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide is 1:(5-10), and the particle size is 20-50 nm.

[0026] Optionally, the mass of the second copolymer is 10-15% of the mass of the second mixture;

[0027] The mass of the Ag@rGO nanoparticles is 5-8% of the mass of the second mixture;

[0028] The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 1×10 10 ~5×1011 .

[0029] In a second aspect, the present application provides an exosome-integrated antibacterial polymer material obtained by the preparation method of the exosome-integrated antibacterial polymer material described in any one of the embodiments of the first aspect, wherein the exosome-integrated antibacterial polymer material is used for repairing chronic infected wounds.

[0030] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0031] The present application provides a method for preparing an exosome-integrated antimicrobial polymer material. First, the positive charge of a polylysine-chitosan copolymer disrupts bacterial membranes and inhibits metabolic enzyme activity. Combined with the photothermal effect of reduced graphene oxide loaded with silver nanoparticles and the sustained release of silver ions, the material synergistically enhances bactericidal efficacy. Furthermore, covalent coupling of D-glutamic acid and electrostatically adsorbed lipoteichoic acid-binding peptides achieves broad-spectrum targeting, allowing precise enrichment at the site of infection, thereby enhancing antimicrobial performance. Second, a dynamic network gently encapsulates placental mesenchymal stem cell exosomes, allowing for sequential release in response to the infection microenvironment or near-infrared light, promoting angiogenesis, epithelial regeneration, and anti-inflammatory regulation, thereby enhancing repair performance. Third, the Schiff base bonds between aldehyded methylcellulose and amino-chitosan provide self-healing properties, while the coordination bonds between protocatechuic aldehyde and iron ions enhance mechanical strength and adapt to dynamic wound deformation, thereby improving mechanical properties. Finally, a dual pH / photothermal response mechanism enables intelligent controlled release, enabling rapid bactericidal action in the early stages of infection and enhanced intervention by penetrating biofilms in deep infections, reducing the risk of secondary infection and improving environmental responsiveness. Therefore, through multi-mechanism collaborative design and dynamic network optimization, the single function limitation of traditional materials is broken through, and the integration of "antibacterial-repair-self-healing-response" is achieved, while the antibacterial, repair, mechanical properties and environmental responsiveness of exosome-integrated antibacterial polymer materials are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A schematic flow chart of a method for preparing an exosome-integrated antibacterial polymer material provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Figure 1 A schematic flow chart of a method for preparing an exosome-integrated antibacterial polymer material provided in an embodiment of the present application.

[0038] like Figure 1 As shown, the present application provides a method for preparing an exosome-integrated antibacterial polymer material, the method comprising:

[0039] S1, introducing a benzimide bond into the molecular structure of a polylysine-chitosan copolymer to obtain a first copolymer;

[0040] The polylysine (PLL) in the polylysine-chitosan copolymer disrupts bacterial membrane integrity through its positive charge, while chitosan (CS) synergistically kills bacteria by inhibiting the activity of bacterial metabolic enzymes. Furthermore, the polylysine-chitosan copolymer, serving as a copolymer backbone, enables targeted drug release in the infection microenvironment (pH 5.5-6.5) through benzimide bonds (pH responsiveness). Furthermore, the polylysine-chitosan copolymer can be combined with the photothermal effect of Ag@rGO nanoparticles to enhance penetration into drug-resistant bacteria.

[0041] The introduced benzimide bond is pH-responsive and hydrolyzes in an acidic infection environment, triggering the release of antibacterial components (such as PLL and Ag@rGO) to precisely target pathogens. 3+ Coordination bonds) work together to maintain the structural stability of the material under physiological conditions.

[0042] In some embodiments, the introduction of a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer includes: mixing a phosphate buffer of polylysine and a phosphate buffer of chitosan in a molar ratio of 1:1, adding a mixed cross-linker of EDC and NHS, and reacting at 25-30° C. for 10-12 hours, followed by purification to obtain a polylysine-chitosan copolymer; dissolving the polylysine-chitosan copolymer in a DMF solvent, adding p-formylbenzoic acid, stirring and reacting at 60-70° C. under argon protection for 20-28 hours, and then purifying to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain the first copolymer.

[0043] In some embodiments, the molar ratio of EDC to NHS is 1:(0.8-1.2);

[0044] The mass of the p-formylbenzoic acid is 5% to 10% of the mass of the polylysine-chitosan copolymer.

[0045] Polylysine (PLL) is a positively charged polypeptide with broad-spectrum antimicrobial properties, disrupting bacterial membranes through electrostatic interactions. Chitosan (CS) is a natural cationic polysaccharide with excellent antimicrobial and biocompatible properties, promoting wound healing. EDC / NHS crosslinkers, acting as carboxylic acid activators, promote crosslinking between the amino groups of PLL and the carboxyl groups of CS through the formation of active esters, forming a copolymer (PLL-CS). The aldehyde groups of p-formylbenzoic acid condense with the amino groups of PLL-CS to form a benzimide bond (-N=C-), imparting pH responsiveness to the material.

[0046] A high EDC:NHS molar ratio (1:0.8-1:2) ensures sufficient activation of the carboxyl groups and avoids side reactions caused by excess NHS. A reaction temperature (60-70°C) promotes condensation between aldehyde and amino groups while preventing evaporation of the DMF solvent. The amount of p-formylbenzoic acid (5%-10%) balances benzimide bond density and material stability; excessive amounts may lead to excessive cross-linking.

[0047] S2, modifying the first copolymer with a bacteria-targeting ligand by covalently coupling D-glutamic acid and an electrostatically adsorbed lipoteichoic acid-binding peptide to obtain a second copolymer;

[0048] It should be noted that the lipoteichoic acid-binding peptide (LBP-6 or Lipoteichoic acidbinding peptide, source: GenScript, Accession No. NM_059525.5, Definition: Caenorhabditis elegans Fatty acid-binding protein homolog 6 (lbp-6), mRNA) in the examples of this application is an artificially designed short peptide that can specifically bind to lipoteichoic acid (LTA), a major component of the cell wall of Gram-positive bacteria. Its core function is to achieve precise antibacterial effects by targeting and recognizing bacterial surface molecules.

[0049] D-Glu recognizes lipoteichoic acid (LTA) from Gram-positive bacteria through covalent coupling, while LBP-6 targets lipopolysaccharide (LPS) from Gram-negative bacteria through electrostatic adsorption, achieving broad-spectrum antibacterial activity. Simultaneously, the positive charge of LBP-6 binds to the negative charge of bacterial membranes, increasing the material's accumulation efficiency at the site of infection. Furthermore, the D-glutamic acid and lipoteichoic acid-binding peptides synergize with the photothermal sterilization of Ag@rGO, forming a "targeted localization-rapid killing" antibacterial cascade effect.

[0050] In some embodiments, the first copolymer is modified with a bacterial targeting ligand by covalently coupling D-glutamic acid and electrostatically adsorbed lipoteichoic acid-binding peptide to obtain a second copolymer, comprising: mixing a phosphate buffer of D-glutamic acid with a mixed crosslinker of EDC and NHS to activate the carboxyl group, then mixing with the first copolymer, and reacting at 20-30° C. for 4-8 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purifying to obtain a D-Glu-modified copolymer; mixing an aqueous solution of lipoteichoic acid-binding peptide at a concentration of 0.5-2 mg / mL with the D-Glu-modified copolymer, and stirring at pH 5.5-6.5 for 2-6 hours to adsorb the lipoteichoic acid-binding peptide to the surface of the D-Glu-modified copolymer through electrostatic interaction, and then purifying and freeze-drying to obtain the second copolymer.

[0051] In some embodiments, the molar ratio of EDC to NHS is 1:(0.8-1.2);

[0052] The molar ratio of the D-glutamic acid to the first copolymer is 1:(1.5-2);

[0053] The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:(8-12).

[0054] EDC / NHS activation: activates the carboxyl group of D-Glu to form an amide bond with the amino group of PLL-CS-Bz.

[0055] The molar ratio (D-Glu: first copolymer = 1:1.5-2) ensures sufficient targeting ligand density and enhances recognition of Gram-positive bacteria (LTA). Phosphate buffer optimizes EDC / NHS activation efficiency and avoids acidic conditions that can cause chitosan precipitation.

[0056] The mass ratio of lipoteichoic acid-binding peptide to D-Glu-modified copolymer (1:(8-12)) allows for electrostatic binding between the positive charge of LBP-6 and the negative charge of the copolymer (after D-Glu modification), targeting Gram-negative bacteria (LPS). A pH range of 5.5-6.5 simulates the infection microenvironment, enhancing adsorption efficiency while preventing peptide structural denaturation.

[0057] S3, mixing the phosphate buffer solution of the aldehyded methylcellulose and the phosphate buffer solution of the amino-chitosan to obtain a first mixture;

[0058] Aldehyde methylcellulose (A-MC) and amino chitosan (NH2-CS) can form reversible crosslinks through Schiff base bonds (-C=N-), giving the material self-healing properties and adapting to wound deformation. At the same time, gentle physical wrapping reduces damage to the exosome membrane and maintains the integrity of active ingredients such as miRNA and proteins carried by it. In addition, aldehyde methylcellulose (A-MC) and amino chitosan (NH2-CS) can form reversible crosslinks with protocatechualdehyde-Fe 3+ The coordination bonds form a dual dynamic network, which enhances mechanical strength and responds to near-infrared light controlled release. 3+ The coordination bonds form a mild encapsulation structure, preventing exosomes from being inactivated by physical extrusion or oxidative stress.

[0059] In some embodiments, the concentration of the phosphate buffer of the aldehyded methylcellulose is 8-12 wt %, the concentration of the phosphate buffer of the amino-chitosan is 2-4 wt %, and the mixing volume ratio is 1:(0.8-1.2).

[0060] The concentration of aldehyde-modified methylcellulose (A-MC) (8-12 wt%) provides sufficient aldehyde group density to ensure the strength of subsequent Schiff base crosslinks. The concentration of amino-modified chitosan (NH2-CS) (2-4 wt%) prevents excessive amino group density from inducing agglomeration while ensuring dynamic network formation. A mixing volume ratio of 1:(0.8-1.2) balances the aldehyde-to-amino molar ratio and optimizes the formation efficiency of dynamic Schiff base bonds (-C=N-).

[0061] In some embodiments, the preparation method of the aldehyded methylcellulose comprises the following steps: dispersing 2 g of methylcellulose in 100 mL of PBS (pH 5.0), stirring at 60° C. for 2 hours until completely dissolved, cooling to room temperature, adding 0.8 g of sodium periodate (MC:NaIO4 molar ratio 1:1.2), stirring and reacting at room temperature for 8 hours under light-proof conditions, adding 5 mL of ethylene glycol, and continuing to stir for 1 hour to neutralize unreacted NaIO4; placing the reaction solution into a dialysis bag, dialyzing with deionized water for 3 days (changing the water 3 times a day) to remove small molecular byproducts; and freeze-drying the solution after dialysis (-50° C., 24 hours) to obtain a white sponge-like aldehyded methylcellulose (A-MC).

[0062] In some embodiments, the preparation method of the amino chitosan (NH2-CS) comprises the following steps: dissolving 1 g of chitosan in 50 mL of 2% acetic acid solution, stirring until transparent, adding 0.5 g of adipic anhydride (CS: adipic anhydride molar ratio of 1:2), and reacting at 50°C for 24 hours; transferring the carboxylated chitosan solution to DMF, adding EDC (0.8 mmol) and NHS (0.8 mmol), stirring at room temperature for 30 minutes, adding ethylenediamine (2 mmol, carboxyl: ethylenediamine = 1:2), and reacting at 30°C for 12 hours; dialyzing (deionized water, 3 days) to remove unreacted ethylenediamine and by-products, and freeze-drying to obtain the amino chitosan (NH2-CS).

[0063] S4, adding a mixture of protocatechuic aldehyde and FeCl3 solution to the first mixture, and adjusting the pH to 6.0-7.0 to obtain a second mixture;

[0064] In the protocatechuic aldehyde and FeCl3, the catechol group of protocatechuic aldehyde reacts with Fe 3+ The tridentate coordination bond is formed to enhance the mechanical properties and photothermal responsiveness of the material. 3+ The dissociation of coordination bonds releases heat (ΔT ≥ 50 ° C), which accelerates the Ag@rGO + release.

[0065] In some embodiments, the molar ratio of protocatechualdehyde to FeCl3 is (3-4):1, and the Fe in the second mixture is 3+ The final concentration is 0.08~0.12M.

[0066] The molar ratio of protocatechuic aldehyde to FeCl3 is (3-4):1. Each protocatechuic aldehyde molecule provides 3 catechol groups. 3+ Form a stable tridentate coordination bond. Fe 3+ The final concentration (0.08-0.12 M) can ensure the coordination bond density and endow the material with self-healing and photothermal responsiveness.

[0067] S5. Under stirring, the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles are added to the second mixture, and the mixture is allowed to stand to obtain the exosome-integrated antibacterial polymer material.

[0068] The high specific surface area and photothermal conversion efficiency of rGO of Ag@rGO nanoparticles can achieve local heating sterilization, and Ag nanoparticles release Ag + Interfere with bacterial metabolism. At the same time, the positive charge of Ag@rGO nanoparticles and PLL synergize to destroy bacterial biofilm and enhance the permeability of antimicrobial peptides. In addition, Ag@rGO nanoparticles can interact with the dynamic network of protocatechualdehyde-Fe 3+ The coordination bond combination realizes the dual antibacterial mode of "photothermal triggering-chemical sterilization".

[0069] Placental mesenchymal stem cell exosomes (PMSC-exosomes) carry miRNAs (such as miR-21-5p) and growth factors (such as VEGF) that promote angiogenesis and epithelial regeneration. They also inhibit macrophage M1 polarization, alleviating excessive inflammatory responses at the site of infection. Furthermore, dynamic bond dissociation within the infected microenvironment allows for sustained repair through the sustained release of exosomes. Following rapid sterilization by Ag@rGO, the exosomes repair damaged tissue, preventing secondary infection.

[0070] In some embodiments, the Ag@rGO nanoparticles are synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide is 1:(5-10), and the particle size is 20-50 nm.

[0071] Limit the AgNO3:rGO mass ratio to 1:5-10, control the Ag loading amount, and avoid Ag + Burst toxicity. The particle size is limited to 20-50 nm. The small size can enhance the photothermal effect while avoiding cellular phagocytosis.

[0072] In some embodiments, the mass of the second copolymer is 10-15% of the mass of the second mixture;

[0073] The mass of the Ag@rGO nanoparticles is 5-8% of the mass of the second mixture;

[0074] The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 1×10 10 ~5×10 11 .

[0075] In some embodiments, the preparation method of the Ag@rGO nanoparticles includes: dispersing 50 mg of GO in 100 mL of deionized water, ultrasonically treating (power 300 W, frequency 40 kHz) for 1 hour to obtain a uniform GO suspension (0.5 mg / mL); adding 0.1 M ascorbic acid (GO to ascorbic acid mass ratio 1:5) to the GO suspension, stirring in an 80°C water bath for 6 hours, the solution changes from brown to black, indicating that GO is reduced to rGO; centrifuging (8000×g, 15 minutes) to remove the unreacted reducing agent, washing the precipitate with deionized water 3 times, and re-dispersing it in 50 mL of water to obtain an rGO dispersion (1 mg / mL); weighing AgNO3 according to the AgNO3:rGO mass ratio of 1:5 to 1:10 (for example, taking 10 mg of AgNO3 corresponding to 50 to 100 mg rGO) was dissolved in 10 mL of deionized water and stored in the dark. AgNO3 solution was added dropwise to the rGO dispersion and stirred magnetically (500 rpm) for 30 minutes to allow AgNO3 to form a precipitate. + Uniformly adsorbed on the rGO surface; added 0.1M NaBH4 solution (AgNO3 and NaBH4 molar ratio 1:3), stirred under ice bath conditions for 2 hours, the solution gradually changed from colorless to gray-brown, indicating Ag + The precipitate was collected by centrifugation (12,000 × g, 20 minutes), washed three times with ethanol and deionized water to remove unreacted ions and reducing agent, and then freeze-dried at -50°C for 24 hours to obtain Ag@rGO nanoparticle powder.

[0076] In some embodiments, the placental mesenchymal stem cell exosome extraction process includes: centrifuging the placental mesenchymal stem cells to collect the cell supernatant, centrifuging the cell supernatant to remove dead cells and cell debris, filtering through a 0.22 μm filter membrane, and centrifuging at 4°C (at a speed of 10,000 rpm) for 30 minutes to obtain placental mesenchymal stem cell exosomes, which are then stored in an ultra-low temperature refrigerator at -80°C.

[0077] Based on a general inventive concept, the present application provides an exosome-integrated antibacterial polymer material obtained by the preparation method of the exosome-integrated antibacterial polymer material described in any one of the above embodiments, wherein the exosome-integrated antibacterial polymer material is used for repairing chronic infected wounds.

[0078] It can be seen from this that the exosome-integrated antibacterial polymer material provided in the embodiments of the present application has the following effects:

[0079] (1) Synergy between dynamic network and exosomes: Schiff base bonds of aldehyde-modified methylcellulose / amino-modified chitosan encapsulate and protect exosomes, Fe 3+The coordination bond responds to photothermal controlled release, achieving spatiotemporal specific release of exosomes. Simultaneously, the immunomodulatory function of exosomes complements the antibacterial effects of PLL and Ag@rGO, forming an integrated wound repair process of "bactericidal-anti-inflammatory-repair."

[0080] (2) Synergy between targeting ligands and antibacterial components: D-Glu and LBP-6 guide the material to accumulate at the infection site, increasing the local concentration of Ag@rGO and PLL and reducing systemic toxicity. The photothermal effect of Ag@rGO enhances the affinity of the targeting ligand to the bacterial membrane, forming a positive feedback antibacterial mechanism.

[0081] (3) Synergy of photothermal and chemical antibacterial: Near-infrared light triggers Fe 3+ The dissociation of coordination bonds and the rise in temperature of Ag@rGO rapidly kill surface bacteria through dual effects; the pH-responsive release of PLL and Ag by the dynamic network + , inhibit deep infection.

[0082] (4) Synergy between dynamic self-healing and mechanical adaptability: Schiff base bond and Fe 3+ The reversibility of the coordination bonds enables the material to adapt to wound deformation while maintaining uniform dispersion of exosomes and nanoparticles.

[0083] In summary, the exosome-integrated antibacterial polymer material and its preparation method provided in this application have the following advantages:

[0084] (1) Multi-level synergistic antibacterial-repair system: Schiff base bonds of aldehyde-modified methylcellulose / amino-modified chitosan encapsulate exosomes, Fe 3+ The coordination bond responds to near-infrared light (808nm) to trigger release, achieving a "sterilization first, then repair" sequential treatment. At the same time, the miRNA (such as miR-21-5p) carried by exosomes inhibits the release of inflammatory factors (TNF-α, IL-6), complementing the antibacterial effect of polylysine (PLL), forming an "anti-inflammatory-antibacterial-regeneration" closed loop. In addition, D-glutamic acid (D-Glu) and LBP-6 peptides target Gram-positive / negative bacteria, respectively, guiding the enrichment of Ag@rGO nanoparticles at the site of infection, and enhancing local Ag. + The photothermal conversion efficiency of Ag@rGO is ≥50%, which enhances the binding force between the targeting ligand and the bacterial membrane and improves the bactericidal efficiency.

[0085] (2) Intelligent response and adaptive characteristics: The benzimide bond selectively hydrolyzes in the infection microenvironment, accurately releasing antibacterial components (PLL, Ag + ). Near-infrared light dissociates Fe 3+ Coordination bond accelerates the responsive release of Ag@rGO and exosomes. 3+The reversibility of the coordination bond enables the material to achieve a self-healing efficiency of ≥90% within 30 minutes, adapting to wound deformation.

[0086] (3) Highly effective in resisting drug resistance and biosafety: The positive charges of PLL and chitosan (CS) synergistically destroy bacterial membranes (zeta potential +25mV), bypassing the traditional antibiotic resistance mechanism. + Inhibit bacterial respiratory chain enzyme activity, and the photothermal effect directly kills the biofilm of drug-resistant bacteria. The biocompatibility of chitosan, polylysine and exosomes reduces the risk of immune rejection. + The cumulative release rate within 72 hours is ≤30%, avoiding the toxicity of sudden release of metal ions.

[0087] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are generally measured according to industry standards. If there are no corresponding industry standards, then the methods are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0088] Example 1

[0089] This embodiment provides a method for preparing an exosome-integrated antibacterial polymer material, the method comprising:

[0090] S11. Mix polylysine (ε-polylysine: CAS No.: 28211-04-3) in phosphate buffer (general buffer pH 7.4) and chitosan (CAS No.: 9012-76-4, deacetylation degree ≥ 75%) in phosphate buffer at a molar ratio of 1:1, add EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, CAS No.: 25952-53-8) and NHS (N-hydroxysuccinimide) imide, CAS number: 6066-82-6) and reacting at 30° C. for 10 hours, followed by purification to obtain a polylysine-chitosan copolymer; dissolving the polylysine-chitosan copolymer in DMF solvent, adding p-formylbenzoic acid, stirring and reacting at 70° C. under argon protection for 24 hours, and then purifying to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer;

[0091] Among them, the molar ratio of EDC to NHS is 1:1;

[0092] The mass of the p-formylbenzoic acid is 7% of the mass of the polylysine-chitosan copolymer.

[0093] S21. D-glutamic acid (CAS No.: 6893-26-1) in phosphate buffer is mixed with a mixed cross-linker of EDC and NHS to activate the carboxyl group, and then mixed with the first copolymer and reacted at 30° C. for 6 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purified to obtain a D-Glu-modified copolymer; a 1 mg / mL aqueous solution of lipoteichoic acid-binding peptide (LBP-6 or Lipoteichoic acid binding peptide, source: GenScript, Accession No.: NM_059525.5, Definition: Caenorhabditis elegans Fattyacid-binding protein homolog 6 (lbp-6), mRNA.) is mixed with the D-Glu-modified copolymer, and stirred at pH 5 for 4 hours to adsorb the lipoteichoic acid-binding peptide to the surface of the D-Glu-modified copolymer through electrostatic interaction, and then purified and lyophilized to obtain a second copolymer;

[0094] Among them, the molar ratio of EDC to NHS is 1:1;

[0095] The molar ratio of the D-glutamic acid to the first copolymer is 1:1.8;

[0096] The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:10.

[0097] S31, mixing a phosphate buffer solution of aldehyde-modified methylcellulose (basic material methylcellulose CAS number: 9004-67-5) and a phosphate buffer solution of amino-modified chitosan to obtain a first mixture;

[0098] The concentration of the phosphate buffer of the aldehyded methylcellulose is 10 wt %, the concentration of the phosphate buffer of the amino-chitosan is 3 wt %, and the mixing volume ratio is 1:1.

[0099] S41, adding a mixture of protocatechuic aldehyde (CAS No.: 139-85-5) and FeCl3 solution to the first mixture, and adjusting the pH to 6.0 to obtain a second mixture;

[0100] The molar ratio of protocatechuic aldehyde to FeCl3 is 3.5:1, and the Fe 3+ The final concentration is 0.1M.

[0101] S51. Under stirring, adding the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles to the second mixture, and allowing it to stand to obtain the exosome-integrated antibacterial polymer material.

[0102] The Ag@rGO nanoparticles were synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide was 1:8, and the average particle size was 30 nm.

[0103] The mass of the second copolymer is 12% of the mass of the second mixture;

[0104] The mass of the Ag@rGO nanoparticles is 6% of the mass of the second mixture;

[0105] The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 7×10 10 .

[0106] Example 2

[0107] This embodiment provides a method for preparing an exosome-integrated antibacterial polymer material, the method comprising:

[0108] S11, mixing a phosphate buffer solution of polylysine and a phosphate buffer solution of chitosan in a molar ratio of 1:1, adding a mixed cross-linking agent of EDC and NHS, and reacting at 30° C. for 10 hours, and then purifying to obtain a polylysine-chitosan copolymer; dissolving the polylysine-chitosan copolymer in a DMF solvent, adding p-formylbenzoic acid, and stirring and reacting at 70° C. under argon protection for 20 hours, and then purifying to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer;

[0109] Among them, the molar ratio of EDC to NHS is 1:1.2;

[0110] The mass of the p-formylbenzoic acid is 10% of the mass of the polylysine-chitosan copolymer.

[0111] S21, mixing a phosphate buffer of D-glutamic acid with a mixed cross-linker of EDC and NHS to activate the carboxyl group, then mixing with the first copolymer, and reacting at 30° C. for 4 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purifying to obtain a D-Glu-modified copolymer; mixing a 2 mg / mL aqueous solution of lipoteichoic acid-binding peptide with the D-Glu-modified copolymer, and stirring at pH 6.5 for 6 hours to adsorb the lipoteichoic acid-binding peptide to the surface of the D-Glu-modified copolymer through electrostatic interaction, and then purifying and lyophilizing to obtain a second copolymer;

[0112] Among them, the molar ratio of EDC to NHS is 1:1.2;

[0113] The molar ratio of the D-glutamic acid to the first copolymer is 1:2;

[0114] The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:12.

[0115] S31, mixing the phosphate buffer solution of the aldehyded methylcellulose and the phosphate buffer solution of the amino-chitosan to obtain a first mixture;

[0116] The concentration of the phosphate buffer of the aldehyded methylcellulose is 8-12 wt %, the concentration of the phosphate buffer of the amino chitosan is 2-4 wt %, and the mixing volume ratio is 1:1.2.

[0117] S41, adding a mixture of protocatechuic aldehyde and FeCl3 solution to the first mixture, and adjusting the pH to 7.0 to obtain a second mixture;

[0118] Wherein, the molar ratio of protocatechuic aldehyde to FeCl3 is 4:1, and the Fe in the second mixture is 3+ The final concentration is 0.12M.

[0119] S51. Under stirring, adding the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles to the second mixture, and allowing it to stand to obtain the exosome-integrated antibacterial polymer material.

[0120] The Ag@rGO nanoparticles were synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide was 1:10, and the average particle size was 50 nm.

[0121] The mass of the second copolymer is 15% of the mass of the second mixture;

[0122] The mass of the Ag@rGO nanoparticles is 8% of the mass of the second mixture;

[0123] The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 5×10 11 .

[0124] Example 3

[0125] This embodiment provides a method for preparing an exosome-integrated antibacterial polymer material, the method comprising:

[0126] S11, mixing a phosphate buffer solution of polylysine and a phosphate buffer solution of chitosan in a molar ratio of 1:1, adding a mixed cross-linking agent of EDC and NHS, and reacting at 25° C. for 12 hours, and then purifying to obtain a polylysine-chitosan copolymer; dissolving the polylysine-chitosan copolymer in a DMF solvent, adding p-formylbenzoic acid, and stirring and reacting at 60° C. under argon protection for 28 hours, and then purifying to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer;

[0127] Among them, the molar ratio of EDC to NHS is 1:0.8;

[0128] The mass of the p-formylbenzoic acid is 5% of the mass of the polylysine-chitosan copolymer.

[0129] S21, mixing a phosphate buffer of D-glutamic acid with a mixed cross-linker of EDC and NHS to activate the carboxyl group, and then mixing with the first copolymer, and reacting at 20° C. for 8 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purifying to obtain a D-Glu-modified copolymer; mixing an aqueous solution of lipoteichoic acid-binding peptide at a concentration of 0.5 to 2 mg / mL with the D-Glu-modified copolymer, and stirring at pH 5.5 for 2 hours to adsorb the lipoteichoic acid-binding peptide to the surface of the D-Glu-modified copolymer through electrostatic interaction, and then purifying and lyophilizing to obtain a second copolymer;

[0130] Among them, the molar ratio of EDC to NHS is 1:0.8;

[0131] The molar ratio of the D-glutamic acid to the first copolymer is 1:1.5;

[0132] The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:8.

[0133] S31, mixing the phosphate buffer solution of the aldehyded methylcellulose and the phosphate buffer solution of the amino-chitosan to obtain a first mixture;

[0134] The concentration of the phosphate buffer of the aldehyded methylcellulose is 8 wt %, the concentration of the phosphate buffer of the amino chitosan is 2 wt %, and the mixing volume ratio is 1:0.8.

[0135] S41, adding a mixture of protocatechuic aldehyde and FeCl3 solution to the first mixture, and adjusting the pH to 6.0-7.0 to obtain a second mixture;

[0136] The molar ratio of protocatechuic aldehyde to FeCl3 is 3:1, and the Fe in the second mixture is3+ The final concentration is 0.08M.

[0137] S51. Under stirring, adding the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles to the second mixture, and allowing it to stand to obtain the exosome-integrated antibacterial polymer material.

[0138] The Ag@rGO nanoparticles were synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide was 1:5, and the average particle size was 20 nm.

[0139] The mass of the second copolymer is 10% of the mass of the second mixture;

[0140] The mass of the Ag@rGO nanoparticles is 5% of the mass of the second mixture;

[0141] The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 1×10 10 .

[0142] Comparative Example 1

[0143] This comparative example is modified as follows based on Example 1:

[0144] A benzimide bond is introduced into the molecular structure of polylysine to obtain a first copolymer.

[0145] Comparative Example 2

[0146] This comparative example is modified as follows based on Example 1:

[0147] A benzimide bond is introduced into the molecular structure of chitosan to obtain a first copolymer.

[0148] Comparative Example 3

[0149] This comparative example is modified as follows based on Example 1:

[0150] No benzimide bond is introduced in step S11, that is, the first copolymer is a polylysine-chitosan copolymer.

[0151] Comparative Example 4

[0152] This comparative example is modified as follows based on Example 1:

[0153] No covalent coupling of D-glutamic acid was performed in step S21.

[0154] Comparative Example 5

[0155] This comparative example is modified as follows based on Example 1:

[0156] Electrostatic adsorption of lipoteichoic acid-binding peptides was not performed in step S21.

[0157] Comparative Example 6

[0158] This comparative example is modified as follows based on Example 1:

[0159] Step S41 is not performed, that is, the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles are directly added to the first mixture.

[0160] Comparative Example 7

[0161] This comparative example is modified as follows based on Example 1:

[0162] No Ag@rGO nanoparticles were added to the second mixture, that is, the second copolymer and placental mesenchymal stem cell exosomes were added to the second mixture.

[0163] Comparative Example 8

[0164] This comparative example is modified as follows based on Example 1:

[0165] The second copolymer was not added to the second mixture, that is, the placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles were added to the second mixture.

[0166] The performance of the exosome-integrated antibacterial polymer materials obtained in Examples 1 to 3 and Comparative Examples 1 to 8 was measured, and the results are shown in Tables 1 and 2. The performance measurement method is as follows:

[0167] Minimum inhibitory concentration (MIC): ISO 20776-1;

[0168] Bactericidal rate test: co-culture with MRSA and E. coli for 24 hours;

[0169] Endothelial cell proliferation assay: CCK-8 method;

[0170] Keratinocyte migration assay: scratch method;

[0171] Inflammatory factor detection: ELISA method (Human TNF-α ELISA Kit, Abcam, ab181421);

[0172] Compression modulus test: ASTM D695;

[0173] Self-healing efficiency test: recovery time and strength after damage (cut the sample and let it stand for self-healing, testing the ratio of tensile strength before and after repair);

[0174] Targeting: Fluorescent labeling method (co-incubation of labeled materials with bacteria to detect enrichment rate at the infection site).

[0175] Table 1 Performance of exosome-integrated antibacterial polymer materials of Examples 1 to 3

[0176]

[0177] As shown in Table 1, Examples 1-3 achieved comprehensive improvements in antimicrobial, repair, mechanical, and environmental responsiveness through multi-component collaborative design (polylysine-chitosan copolymer, targeting ligand, Ag@rGO, exosomes) and dynamic network optimization (pH / photothermal response, self-healing). The exosome-integrated antimicrobial polymer materials in Examples 1-3 exhibited MICs of 2.4-2.6 μg / mL, bactericidal rates ≥99.8%, biofilm inhibition rates ≥95%, endothelial proliferation rates ≥2.0-fold, keratin migration rates ≥40%, TNF-α levels of 110-120 pg / mL, moduli ≥500 Pa, self-healing efficiencies ≥90%, and targeted enrichment rates ≥70%.

[0178] Table 2 Performance of exosome-integrated antibacterial polymer materials of comparative examples 1 to 8

[0179]

[0180] In Comparative Example 1, only a benzimide bond was introduced into polylysine, resulting in the loss of the metabolic enzyme inhibition function of chitosan and insufficient targeting, resulting in decreased antibacterial and repair properties.

[0181] In Comparative Example 2, only benzimide bonds were introduced into chitosan, and the membrane-breaking effect of the positive charge of polylysine was weakened, and the antibacterial efficiency was reduced.

[0182] In Comparative Example 3, no benzimide bond was introduced, the pH-responsive release mechanism failed, the antibacterial components could not be released in a targeted manner, and the exosome repair activity was reduced.

[0183] In Comparative Example 4, D-glutamic acid was not coupled, and the targeting of Gram-positive bacteria was lost, the local antibacterial concentration was insufficient, and the bactericidal rate decreased.

[0184] In Comparative Example 5, no LBP-6 peptide was adsorbed, the Gram-negative bacteria targeting ability was lost, and the bactericidal effect on Escherichia coli and the like was weakened.

[0185] In Comparative Example 6, Fe was not introduced. 3+ Coordination bonds, lack of photothermal responsiveness, inability to intervene in deep infections, and reduced mechanical strength.

[0186] In comparative example 7, Ag@rGO was not added, and the photothermal sterilization and Ag + Sustained-release function, the clearance rate of drug-resistant bacteria is greatly reduced.

[0187] In Comparative Example 8, the second copolymer was not added, the targeting ligand and the antibacterial component were missing, and the material function was completely ineffective.

[0188] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0189] In addition, in the description of this application, the terms "including", "comprising", etc. mean "including but not limited to". In this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0190] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing exosome-integrated antibacterial polymer materials, characterized in that: The method comprises: introducing a benzimide bond into the molecular structure of a polylysine-chitosan copolymer to obtain a first copolymer; Modifying the first copolymer with a bacteria-targeting ligand by covalently coupling D-glutamic acid and an electrostatically adsorbed lipoteichoic acid binding peptide to obtain a second copolymer; Mixing the phosphate buffer solution of aldehyde-modified methylcellulose and the phosphate buffer solution of amino-modified chitosan to obtain a first mixture; adding a mixture of protocatechuic aldehyde and FeCl3 solution to the first mixture and adjusting the pH to 6.0-7.0 to obtain a second mixture; Under stirring, the second copolymer, placental mesenchymal stem cell exosomes and Ag@rGO nanoparticles are added to the second mixture, and the mixture is allowed to stand to obtain the exosome-integrated antibacterial polymer material.

2. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The first copolymer is obtained by introducing a benzimide bond into the molecular structure of the polylysine-chitosan copolymer, comprising: The phosphate buffer solution of polylysine and the phosphate buffer solution of chitosan are mixed in a molar ratio of 1:1, a mixed cross-linking agent of EDC and NHS is added, and the mixture is reacted at 25-30° C. for 10-12 hours, and then purified to obtain a polylysine-chitosan copolymer; The polylysine-chitosan copolymer is dissolved in a DMF solvent, and p-formylbenzoic acid is added. The mixture is stirred and reacted at 60-70° C. under argon protection for 20-28 hours, and then purified to introduce a benzimide bond into the molecular structure of the polylysine-chitosan copolymer to obtain a first copolymer.

3. The method for preparing the exosome-integrated antibacterial polymer material according to claim 2, characterized in that: The molar ratio of EDC to NHS is 1:(0.8-1.2); The mass of the p-formylbenzoic acid is 5% to 10% of the mass of the polylysine-chitosan copolymer.

4. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The first copolymer is modified with a bacteria-targeting ligand by covalently coupling D-glutamic acid and an electrostatically adsorbed lipoteichoic acid binding peptide to obtain a second copolymer, comprising: Mixing a phosphate buffer of D-glutamic acid with a mixed crosslinker of EDC and NHS to activate the carboxyl group, then mixing with the first copolymer and reacting at 20-30° C. for 4-8 hours to couple the amide bond of the activated D-glutamic acid to the surface of the first copolymer, and then purifying to obtain a D-Glu modified copolymer; An aqueous solution of lipoteichoic acid binding peptide with a concentration of 0.5 to 2 mg / mL is mixed with a D-Glu modified copolymer and stirred for 2 to 6 hours at a pH of 5.5 to 6.5 to adsorb the lipoteichoic acid binding peptide to the surface of the D-Glu modified copolymer through electrostatic interaction. The mixture is then purified and freeze-dried to obtain a second copolymer.

5. The method for preparing the exosome-integrated antibacterial polymer material according to claim 4, characterized in that: The molar ratio of EDC to NHS is 1:(0.8-1.2); The molar ratio of the D-glutamic acid to the first copolymer is 1:(1.5-2); The mass ratio of the lipoteichoic acid binding peptide to the D-Glu modified copolymer is 1:(8-12).

6. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The concentration of the phosphate buffer of the aldehyded methylcellulose is 8-12 wt %, the concentration of the phosphate buffer of the amino chitosan is 2-4 wt %, and the mixing volume ratio is 1:(0.8-1.2).

7. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The molar ratio of protocatechuic aldehyde to FeCl3 is (3-4):

1. 3+ The final concentration is 0.08~0.12M.

8. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The Ag@rGO nanoparticles are synthesized by a chemical reduction method, the mass ratio of AgNO3 to reduced graphene oxide is 1:(5-10), and the particle size is 20-50 nm.

9. The method for preparing the exosome-integrated antibacterial polymer material according to claim 1, characterized in that: The mass of the second copolymer is 10% to 15% of the mass of the second mixture; The mass of the Ag@rGO nanoparticles is 5-8% of the mass of the second mixture; The number of particles of placental mesenchymal stem cell exosomes per gram of the second mixture is 1×10 10 ~5×10 11 .

10. An exosome-integrated antimicrobial polymer material obtained by the preparation method of the exosome-integrated antimicrobial polymer material according to any one of claims 1 to 9, characterized in that: The exosomes are integrated with antibacterial polymer materials for use in repairing chronic infected wounds.

Images