Preparation method of antibacterial hydrogel for infectious diabetes wound healing

Abstract

The invention relates to the technical field of high polymer materials, in particular to a preparation method of antibacterial hydrogel for infectious diabetes wound healing, chitosan and tobramycin are used as dynamic physical cross-linking agents, and the hydrogel is prepared through free radical polymerization of N-acryloyl triester (hydroxymethyl) aminomethane and acrylic acid under the irradiation of an ultraviolet lamp. Through electrostatic interaction between carboxyl of the copolymer and amino of the tobramycin, the tobramycin is incorporated into a hydrogel network, so that the mechanical strength is increased, and drug release is controlled. Chitosan exists as another cross-linking agent, so that the mechanical strength of the hydrogel can be adjusted. The hydrogel has an easy-to-synthesize process and sufficient mechanical strength and adhesion, and has the potential of providing a promising and practical combined treatment method for effectively treating chronic infectious diabetes wounds.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a method for preparing an antibacterial hydrogel for healing infectious diabetic wounds. Background Art

[0002] Diabetes is a chronic metabolic disorder often accompanied by a variety of hyperglycemia-related complications. Wounds in diabetic patients are at high risk of bacterial infection and delayed healing, which may be due to the high-sugar environment at the wound site and local vascular and nerve damage. In addition, the immune system of diabetic patients is impaired, making the wound less resistant to bacterial infection. Despite surgical and drug interventions, the treatment of infected diabetic wounds remains challenging and may lead to serious complications such as long-term non-healing, necrosis, and fibrosis. Therefore, there is an urgent need to develop effective and suitable diabetic wound repair dressings.

[0003] Over the years, various types of wound dressings have been developed and used for skin healing, including sponges, gauze, powders, bandages, and hydrogels. Among them, hydrogels with inherent porosity have demonstrated their superior ability to promote tissue regeneration by creating a humid environment. In addition, the reduced viscosity of hydrophilic hydrogels after absorbing water makes it easy to remove it from the skin, thereby reducing pain and the risk of secondary injury. Despite this, the hydrogel materials currently used in clinical practice have the disadvantages of weak adhesion to tissue surfaces, poor tissue-like mechanics, slow degradation rates, and poor antibacterial effects. Therefore, the development of hydrogels with strong adhesion, strong mechanical properties, adjustable biodegradability, and drug release is a scientific problem that urgently needs to be solved in the clinical practice of diabetic wound treatment.

[0004] Adhesive hydrogels have emerged as a promising solution for wound healing because they can be securely fixed to the skin surface to prevent dressing detachment and secondary contamination. In recent decades, researchers have developed a large number of adhesive hydrogels for wound healing based on different adhesion mechanisms. For example, Schiff base hydrogels rely on the interaction between aldehyde and amino groups in tissues for adhesion, but their clinical application is limited by weak interfacial toughness. Similarly, natural dopamine hydrogels have been shown to enhance adhesion through interactions between catechol groups and amino or thiol groups in tissues, but exposure to air oxidation of the catechol groups of dopamine to quinone groups results in reduced flexibility and loss of adhesion. In addition, dynamic non-covalent bond-driven hydrogels have also become a promising solution for wound healing due to their good adhesion and flexibility. Some researchers have explored the use of N-trimethylolmethyl acrylamide to create new adhesive hydrogels with improved properties. However, N-trimethylolmethyl acrylamide-based hydrogels still face challenges in achieving effective closure of moving parts due to insufficient mechanical strength and tensile properties.

[0005] In the present invention, a highly stretchable adhesive and antibacterial hydrogel with multiple dynamic non-covalent bonds based on N-trimethylolmethyl acrylamide are developed. This hydrogel is designed to promote wound healing and tissue regeneration of diabetic wounds, and has the advantages of appropriate adhesion, strong mechanical properties, adjustable biodegradability and controlled drug release. Due to the dynamic properties of the hydrogel, its elongation capacity exceeds 1600%, and the tissue adhesion stress is up to 10kPa. The experimental results also show that the hydrogel has good biocompatibility, antibacterial properties, accelerates the healing of diabetic wounds and reduces the formation of scars. At the same time, the hydrogel has an easy synthesis process, sufficient mechanical strength and adhesion, and has the potential to provide a promising and practical combined treatment method for the effective treatment of chronic diabetic wounds. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing an antibacterial hydrogel for healing of infectious diabetic wounds, wherein chitosan and tobramycin are used as dynamic physical crosslinkers, and the hydrogel is prepared by free radical polymerization of N-acryloyl triester (hydroxymethyl) aminomethane and acrylic acid under ultraviolet light. Tobramycin is incorporated into the hydrogel network through the electrostatic interaction between the carboxyl group of the copolymer and the amino group of tobramycin, thereby increasing the mechanical strength and controlling the drug release. Chitosan exists as another crosslinker to adjust the mechanical strength of the hydrogel.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] A method for preparing an antibacterial hydrogel for healing infectious diabetic wounds comprises the following steps: mixing chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water to form a hydrogel precursor solution, adding the precursor solution into a mold and irradiating it with ultraviolet light to obtain an antibacterial hydrogel.

[0009] Furthermore, the chitosan and tobramycin are dynamic physical crosslinkers, and the hydrogel is prepared by free radical polymerization of N-acryloyl triester (hydroxymethyl) aminomethane and acrylic acid under ultraviolet light. Through the electrostatic interaction between the carboxyl group of the copolymer and the amino group of tobramycin, tobramycin is incorporated into the hydrogel network, thereby increasing the mechanical strength and controlling the drug release.

[0010] Furthermore, the amount of chitosan used is related to the mechanical strength of the hydrogel.

[0011] Furthermore, the weight proportions of the components in the precursor solution are: 20-60 parts of chitosan, 6-12 parts of tobramycin, 100-300 parts of acrylic acid, 200-600 parts of N-trimethylolmethyl acrylamide, 5-15 parts of α-ketoglutaric acid, and 1200-3600 parts of distilled water.

[0012] Furthermore, the weight ratio of each component in the precursor solution is: 30 parts of chitosan, 9 parts of tobramycin, 200 parts of acrylic acid, 400 parts of N-trihydroxymethyl methacrylamide, 10 parts of α-ketoglutaric acid, and 2400 parts of distilled water.

[0013] Furthermore, the molecular weight of the chitosan is 180-220 kDa, and the degree of deacetylation is 85-95%.

[0014] Furthermore, the molecular weight of the chitosan is 200 kDa, and the degree of deacetylation is 90%.

[0015] Furthermore, the precursor solution is subjected to ultrasonic deoxygenation for 2 minutes before being added to the mold.

[0016] Furthermore, the irradiation time of the ultraviolet light is 0.5-1h.

[0017] On the other hand, in the above preparation method proposed by the present invention, the equivalent substitute of chitosan is a polymer containing amino group, including but not limited to gelatin and polylysine.

[0018] Beneficial effects of the present invention:

[0019] 1. Promote healing and tissue regeneration of diabetic wounds: The hydrogel uses its dynamic non-covalent bond characteristics to form a stretchable network structure, providing appropriate adhesion and strong mechanical properties. This network structure can be closely integrated with the wound tissue to promote wound healing and tissue regeneration. At the same time, the hydrogel's appropriate adhesion helps prevent dressing detachment and secondary contamination, and improves the success rate of wound healing.

[0020] 2. Effectively prevent infection: Using tobramycin as an antibacterial agent and incorporating it into the hydrogel network can achieve antibacterial effects against a variety of bacteria. Tobramycin can be stably embedded in the hydrogel structure through the electrostatic interaction between the carboxyl group and the amino group of the copolymer, thereby delaying the release rate of the drug and continuously releasing the antibacterial active ingredients, effectively reducing the risk of diabetic wound infection.

[0021] 3. Adjustable biodegradability: Chitosan, as a cross-linking agent, can adjust the mechanical strength and biodegradability of the hydrogel. Chitosan is a natural polysaccharide with excellent biocompatibility, which can interact with human tissue and gradually degrade. By adjusting the dosage of chitosan, the degree of cross-linking of the hydrogel can be changed, thereby adjusting the mechanical properties and degradation rate of the hydrogel. An appropriate degradation rate is conducive to the growth and regeneration of new tissue on the wound surface.

[0022] 4. Controlled drug release: Tobramycin embedded in the hydrogel can control drug release through electrostatic interactions and the dynamic properties of the hydrogel. The network structure of the hydrogel can limit the diffusion and release of the drug and slow down the release rate of the drug. This controlled release helps maintain a high concentration of the drug at the wound surface and continuously exerts an antibacterial effect, thereby improving the therapeutic effect.

[0023] 5. Easy synthesis process: The preparation method of the hydrogel uses common chemical reagents and equipment, and the operation is simple and easy. By mixing chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water into a hydrogel precursor solution, and then irradiating it with ultraviolet light, an antibacterial hydrogel with excellent performance can be prepared. This simple and easy process helps to improve the production efficiency and feasibility of the hydrogel.

[0024] 6. Excellent physical properties: This technology uses chitosan (CS) and tobramycin (To) as dynamic physical crosslinkers, and prepares hydrogels through free radical polymerization of N-trihydroxymethyl methacrylamide (THMA) and acrylic acid (AA). To is added to the hydrogel network through the electrostatic interaction between the carboxyl group of the copolymer and the amino group of To, thereby increasing the mechanical strength and controlling drug release. The elongation capacity of the hydrogel exceeds 1600%, and the tissue adhesion stress is up to 10kPa.

[0025] In summary, this hydrogel has the advantages of promoting diabetic wound healing and tissue regeneration, effectively preventing infection, and having adjustable biodegradability and drug release, and can be used as a combined treatment method for chronic infectious diabetic wounds.

[0026] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 This is a schematic diagram of the preparation process of the hydrogel of the present invention;

[0029] Figure 2 Characterization diagram of PATCT and PATC hydrogels described in the embodiments of the present invention;

[0030] Figure 3 Schematic diagram of the tensile properties of PATCT and PATC hydrogels described in the embodiments of the present invention;

[0031] Figure 4 Schematic diagram of the adhesion performance of PATCT and PATC hydrogels described in the embodiments of the present invention;

[0032] Figure 5 Schematic diagram of the antibacterial performance of PATCT and PATC hydrogels described in the embodiments of the present invention;

[0033] Figure 6 Schematic diagram of in vitro biocompatibility test of PATCT and PATC hydrogels according to an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the closure process of the wound of diabetic mice infected with Staphylococcus aureus according to an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of the histomorphological manifestation of a scar according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] like Figure 1 Shown

[0039] The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds described in this embodiment comprises the following steps: mixing chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water into a hydrogel precursor solution, adding the precursor solution into a mold and obtaining an antibacterial hydrogel after ultraviolet light irradiation.

[0040] In this embodiment, chitosan and tobramycin are dynamic physical crosslinkers, and the hydrogel is prepared by free radical polymerization of N-acryloyl triester (hydroxymethyl) aminomethane and acrylic acid under ultraviolet light. Tobramycin is incorporated into the hydrogel network through the electrostatic interaction between the carboxyl group of the copolymer and the amino group of tobramycin, thereby increasing the mechanical strength and controlling the drug release.

[0041] In this embodiment, the amount of chitosan used is related to the mechanical strength of the hydrogel.

[0042] In this embodiment, the weight proportions of the components in the precursor solution are: 20-60 parts of chitosan, 6-12 parts of tobramycin, 100-300 parts of acrylic acid, 200-600 parts of N-trimethylolmethyl acrylamide, 5-15 parts of α-ketoglutaric acid, and 1200-3600 parts of distilled water.

[0043] In this embodiment, the weight ratio of each component in the precursor solution is: 30 parts of chitosan, 9 parts of tobramycin, 200 parts of acrylic acid, 400 parts of N-trimethylolmethyl acrylamide, 10 parts of α-ketoglutaric acid, and 2400 parts of distilled water.

[0044] In this embodiment, the molecular weight of the chitosan is 180-220 kDa, and the degree of deacetylation is 85-95%.

[0045] In this embodiment, the molecular weight of the chitosan is 200 kDa, and the degree of deacetylation is 90%.

[0046] In this embodiment, the precursor solution is subjected to ultrasonic deoxygenation for 2 minutes before being added to the mold.

[0047] In this embodiment, the irradiation time of the ultraviolet light is 0.5-1h.

[0048] On the other hand, in the above preparation method proposed by the present invention, the equivalent substitute of chitosan is a polymer containing amino group, including but not limited to gelatin and polylysine.

[0049] Example 2

[0050] The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds described in this embodiment comprises the following steps: mixing chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water into a hydrogel precursor solution, adding the precursor solution into a mold and obtaining an antibacterial hydrogel after ultraviolet light irradiation.

[0051] In this embodiment, the weight ratio of each component in the precursor solution is: 20 parts of chitosan, 6 parts of tobramycin, 100 parts of acrylic acid, 200 parts of N-trihydroxymethyl methacrylamide, 5 parts of α-ketoglutaric acid, and 1200 parts of distilled water.

[0052] In this embodiment, the molecular weight of the chitosan is 180 kDa, and the degree of deacetylation is 85%.

[0053] Example 3

[0054] The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds described in this embodiment comprises the following steps: mixing chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water into a hydrogel precursor solution, adding the precursor solution into a mold and obtaining an antibacterial hydrogel after ultraviolet light irradiation.

[0055] In this embodiment, the weight proportions of the components in the precursor solution are: 40 parts of chitosan, 12 parts of tobramycin, 300 parts of acrylic acid, 600 parts of N-trihydroxymethyl methacrylamide, 15 parts of α-ketoglutaric acid, and 3600 parts of distilled water.

[0056] In this embodiment, the molecular weight of the chitosan is 220 kDa, and the degree of deacetylation is 95%.

[0057] Example 4

[0058] 1. Synthesis of hydrogel ( Figure 1 ):

[0059] 60 mg and 30 mg of chitosan (Mw = 200 kDa, deacetylation degree = 90%), 9 mg of tobramycin, 200 mg of acrylic acid, 400 mg of N-trimethylolmethyl acrylamide, 10 mg of α-ketoglutaric acid and 2.4 g of distilled water were mixed to form a hydrogel precursor solution, and deoxygenated by ultrasonication for 2 minutes. The precursor solution was added to the mold, and hydrogels PATCT1 and PATCT2 were obtained after irradiation with ultraviolet light for 0.5 h. The precursor solution without tobramycin but with the same other formula obtained empty hydrogels PATC1 and PATC2 after ultraviolet light irradiation.

[0060] 2. Characterization of PATCT and PATC Hydrogels ( Figure 2 ):

[0061] Rheological measurements of the hydrogels were performed using a Kinexus rheometer equipped with 25 mm parallel plates. The linear viscoelastic region was determined using an oscillatory amplitude sweep test, and the storage modulus (G') and loss modulus (G") were recorded over a strain range of 0.1% to 1000% ( Figure 2A). Dynamic frequency sweep measurements were performed at a constant strain of 1% and frequencies between 0.1 and 100 Hz to further characterize the rheological properties of the hydrogels ( Figure 2 B).

[0062] The microscopic morphology of the hydrogels was analyzed using scanning electron microscopy (SEM). The freeze-dried hydrogel samples were sliced ​​and mounted on a copper platform, and then metallized before observation to improve conductivity. SEM imaging was performed using a Hitachi Regulus 8230 instrument at an accelerating voltage of 20 kV to visualize the structural morphology of the hydrogels ( Figure 2 C).

[0063] 500 mg of hydrogel was quantitatively placed in 5 ml of PBS (37°C, pH = 7.4) solution and shaken continuously at 100 rpm to measure the drug release kinetics of tobramycin in PATCT1 and PATCT2. Specifically, 1 mL of solution was extracted from the culture medium every 8 hours for quantification of tobramycin, and 1 mL of PBS was added to maintain a constant volume of the liquid. The tobramycin concentration was determined using ninhydrin, and 500 μL of ninhydrin solution (1.25 wt%) and 200 μL of ascorbic acid solution (0.1 wt%) were added to 500 μL of the removed tobramycin solution, and then heated in a 90°C water bath for 20 minutes. Finally, the absorbance of the solution was measured at a wavelength of 570 nm using an ELISA reader (Infinite M200, TECAN, Switzerland). Figure 2 D).

[0064] 3. Tensile properties of PATCT and PATC hydrogels ( Figure 3 ):

[0065] Tensile test: The mechanical properties of the materials were evaluated at room temperature using a universal testing machine (CMT-1104, SUST, Zhuhai, China). Four samples (15 × 15 × 1.5 mm) were tested for each material at a rate of 100 mm / min. The stress-strain curve was used to determine the fracture toughness ( Figure 3 A, B). Adhesive PATCT and PATC hydrogels were tested on the skin surface of the joint and showed good deformation without fracture or delamination ( Figure 3 C).

[0066] 4. Adhesion performance test of PATCT and PATC hydrogels ( Figure 4 ):

[0067] Hydrogels exhibit strong adhesion to various non-biological tissues, such as metal, rubber, glass, and plastic ( Figure 4A). The adhesion of the hydrogel to pig skin was then evaluated using a shear test performed on the universal testing machine described above. The hydrogel (15×15×1.5 mm) was sandwiched between two pig skins (15×30×1.5 mm) with an adhesion area of ​​15×15 mm. The lap shear test was performed at room temperature with a tensile rate of 100 mm / min until failure ( Figure 4 B). Record the force-displacement curve and calculate the adhesion stress ( Figure 4 C). Adhesion stress = maximum force / adhesion area. These hydrogels have moderate tissue adhesion and can be easily peeled off from skin tissue without leaving any residual material ( Figure 4 D) Adhesion mechanism Figure 4 As shown in E.

[0068] 5. In vitro antibacterial activity test of PATCT and PATC hydrogels ( Figure 5 ):

[0069] The antibacterial activity of the hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was determined by the coated plate method and the inhibition ring method.

[0070] For the spread plate method, 1 mL of bacterial suspension (1.0 × 10 7 CFU / mL) were incubated with 20 mg hydrogel and 20 mg PBS at 37°C and 150 rpm for 12 h. Subsequently, 10 μL of bacterial suspension was extracted and diluted 10 5 times, and plated with 50 μL of diluent. Then incubate at 37°C for 24 h and count the colonies ( Figure 5 A, B).

[0071] For the inhibition zone, 100 μL of bacterial suspension (1.0×10 8 CFU / mL) were spread on agar plates and 200 mg of hydrogel was placed on the plates. After incubation at 37°C for 24 h, the samples were photographed and the inhibition zone area ( Figure 5 C, D).

[0072] 6. In vitro biocompatibility testing of PATCT and PATC hydrogels ( Figure 6 ):

[0073] Due to the high hydrophilicity of hydrogels, cells have poor adhesion to their surface. To overcome this problem, we used transwell chambers to obtain the leaching solution of hydrogels ( Figure 6 A) The cytocompatibility of the hydrogel extracts with L929 fibroblasts was evaluated by live / dead cell assay and CCK8 assay.

[0074] In live / dead cell experiments, 1 × 10 4 10 cells / mL complete medium was added to each well of a 24-well plate and placed in a (5% CO 2 , 37°C) incubator overnight. Subsequently, a transwell chamber containing 20 mg of dried hydrogel was placed on top of the plate. After 2 and 4 days, the cells were stained with a live / dead kit, calcein AM stained live cells green, and PI stained dead cells red. The mixed solution was added to each well and removed after treatment at 37°C for 30 minutes. The cells were washed three times with PBS and examined with an Olympus IX71 inverted fluorescence microscope ( Figure 6 B).

[0075] In the CCK-8 assay, cells were seeded in 96-well plates (2×10 4 After incubation with the extract for 24 h, 100 μL of fresh complete medium was added, and 10 μL of CCK-8 reagent was added to culture for 3 h. The absorbance was measured at a wavelength of 450 nm using an ELISA reader (Infinite M200, TECAN, Switzerland). The experiment was repeated 3 times. The calculation formula for cell viability is as follows: Cell viability (%) = As / Ac × 100%. Among them, As and Ac represent the absorbance of the sample group and the control group, respectively ( Figure 6 C).

[0076] 7. PATCT and PATC hydrogels promote wound closure in diabetic mice infected with Staphylococcus aureus ( Figure 7 ):

[0077] The animal experiments were approved by the Institutional Animal Care and Use Committee of Zhujiang Hospital of Southern Medical University. Kunming mice (male, 4 weeks old, 20-25 g) were obtained from the Animal Center of Southern Medical University and acclimated in our laboratory for one week before the experiment. To induce diabetes, mice were injected with STZ (50 mg / kg) for 5 consecutive days. Mice with blood glucose levels exceeding 16.7 mM were considered diabetic mice. To establish a skin wound model of Staphylococcus aureus infection, two circular full-thickness skin wounds (diameter = 5 mm) were created on the back of each mouse under isoflurane anesthesia. Subsequently, 10 μL of Staphylococcus aureus solution (10 8 CFU / mL) introduced into the wound ( Figure 7 A). The mice were randomly divided into 4 different treatment groups (n=10). The left side was treated with gauze only as a control, and the right side was treated with PATCT1, PATCT2, PATC1, and PATC2, respectively ( Figure 7 B). The wound area was photographed on the 5th, 10th and 15th days, and its size was measured using Image J software. PATCT and PATC hydrogels were better at promoting wound healing than the gauze group ( Figure 7C). The calculation formula of wound closure is as follows: Wound closure (%) = (1-At / A0) × 100%. Where At and A0 are the wound areas on day t and day 0, respectively. Figure 7 D) Grind the wound tissue on day 5 and dilute it 10 5 The bacterial plate was counted and the bacterial infection of the wound tissue was evaluated. It was found that PATCT1 and PATCT2 with tobramycin had significantly better antibacterial effect ( Figure 7 E).

[0078] 8. PATCT and PATC hydrogels reduce scar formation in wounds of diabetic mice infected with Staphylococcus aureus ( Figure 8 ):

[0079] To investigate the effect of hydrogel on scar formation, wound tissue sections were stained with HE and Masson trichrome on the 15th day to evaluate scar formation. HE staining results showed that there was no obvious scar tissue in the PATCT1, PATCT2, and PATC1 groups, slight scars in the PATCT2 group, and wide scars in the control group. Masson staining showed that the collagen in the center of the scar in the control group and PATC2 group was sparse parallel bundles, while the collagen in the PATCT1, PATCT2, and PATC1 groups was arranged in a basket-like pattern similar to that of healthy dermis ( Figure 8 A). Quantitative analysis of epidermal thickness, and the number of hair follicles, sebaceous glands, and mature blood vessels showed that PATCT1, PATCT2, and PATC1 were more effective than PATC2 in inhibiting scar formation and reconstructing normal skin structure ( Figure 8 B).

[0080] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an antibacterial hydrogel for healing of infectious diabetic wounds, characterized in that: The following steps are involved: Chitosan, tobramycin, acrylic acid, N-trihydroxymethyl methacrylamide, α-ketoglutaric acid and distilled water are mixed to form a hydrogel precursor solution, and the precursor solution is added into a mold and irradiated with ultraviolet light to obtain an antibacterial hydrogel.

2. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 1, characterized in that: The chitosan and tobramycin are dynamic physical crosslinkers, and the hydrogel is prepared by free radical polymerization of N-acryloyl triester (hydroxymethyl) aminomethane and acrylic acid under ultraviolet light irradiation; tobramycin is incorporated into the hydrogel network through the electrostatic interaction between the carboxyl group of the copolymer and the amino group of tobramycin, thereby achieving the effect of increasing mechanical strength and controlling drug release.

3. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 2, characterized in that: The amount of chitosan used is related to the mechanical strength of the hydrogel.

4. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 1, characterized in that: The weight proportions of the components in the precursor solution are: 20-60 parts of chitosan, 6-12 parts of tobramycin, 100-300 parts of acrylic acid, 200-600 parts of N-trimethylolmethyl acrylamide, 5-15 parts of α-ketoglutaric acid, and 1200-3600 parts of distilled water.

5. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 4, characterized in that: The weight proportions of the components in the precursor solution are: 30 parts of chitosan, 9 parts of tobramycin, 200 parts of acrylic acid, 400 parts of N-trihydroxymethyl methacrylamide, 10 parts of α-ketoglutaric acid, and 2400 parts of distilled water.

6. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 4, characterized in that: The molecular weight of the chitosan is 180-220 kDa, and the deacetylation degree is 85-95%.

7. The method for preparing the antibacterial hydrogel for healing infectious diabetic wounds according to claim 6, characterized in that: The molecular weight of the chitosan is 200 kDa, and the deacetylation degree is 90%.

8. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 1, characterized in that: The precursor solution was subjected to ultrasonic treatment for 2 minutes for deoxygenation before being added to the mold.

9. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to claim 1, characterized in that: The irradiation time of the ultraviolet light is 0.5-1h.

10. The method for preparing an antibacterial hydrogel for healing infectious diabetic wounds according to any one of claims 1 to 9, characterized in that: The equivalent substitutes of chitosan are polymers containing amino groups, including but not limited to gelatin and polylysine.

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