Hydrogel wound dressing for promoting healing of infectious wound as well as preparation method and application of hydrogel wound dressing

Abstract

The invention discloses a hydrogel wound dressing for promoting healing of infectious wounds. The hydrogel wound dressing is prepared from the following raw materials: oxidized methacrylic acid hyaluronic acid, waterborne polyurethane, polylysine, cannabidiol, neomycin sulfate and 2-roots alcohol. The invention also provides a preparation method of the hydrogel wound dressing and application of the hydrogel wound dressing in preparation of products for repairing infectious wounds. The wound dressing provided by the invention has a microporous structure, good biocompatibility and biodegradability, and can be used for stopping bleeding, reducing wound infection and promoting cell proliferation and wound healing.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and particularly relates to a hydrogel wound dressing for promoting the healing of infectious wounds, a preparation method thereof, and an application thereof. Background Art Modern trauma repair research is facing multiple technical bottlenecks. Among them, the deep tissue destruction caused by low-penetration gunshot wounds and the irregular complex trauma formed by explosion shock waves in the battlefield environment are particularly prominent. Such wounds are difficult to achieve effective hemostasis through conventional compression due to their complex morphology, and have become the core issues that need to be overcome urgently in the field of trauma medicine. In the field of precision surgery, nano-level requirements are put forward for the hemostasis accuracy in operations on the nerve center and parenchymal organs. Operations involving cavity structures such as the nasal cavity, ear canal, and urinary tract further test the spatial compliance and biocompatibility of hemostatic materials. From the analysis of tissue regeneration mechanisms, trauma repair follows the chronological process of the hemostasis-inflammatory phase, granulation tissue formation phase, and tissue remodeling phase. Among them, rapid hemostasis within the golden hour after trauma plays a decisive role in shortening the healing cycle. Currently, commonly used clinical dressings generally have the defect of the disconnection between hemostatic efficacy and tissue repair promotion function. Developing a dual-functional integrated medical dressing with both immediate hemostatic effect and long-term tissue regeneration induction ability has become a key research direction in the field of translational medicine.

[0002] The clinical application of wound dressings with good biocompatibility and biodegradability in the body is of great significance. Among them, hyaluronic acid (HA) is a naturally occurring linear polysaccharide widely distributed in human tissues, especially in the extracellular matrix (ECM) of the skin. It has excellent biocompatibility, biodegradability, hydrophilicity, and non-immunogenicity, and plays an important role in the wound healing process. HA can promote cell adhesion, migration, proliferation, and differentiation, and participate in angiogenesis and tissue regeneration. Therefore, it is considered an attractive material for synthesizing biomedical hydrogels for skin wound healing. Aqueous polyurethane (PU) as a dressing material has become a star material in the field of wound repair due to its high designability, modularity, and multi-functional characteristics. Especially some aqueous polyurethane dressings that simulate the skin structure combine the characteristics of high designability, elasticity, breathability, and biocompatibility. Polyurethane dressings can adapt to wounds of different shapes and sizes, provide a moist healing environment, and at the same time protect the wound from external microorganisms. In addition, polyurethane dressings usually have a certain mechanical strength, can withstand friction and pressure during daily activities, reduce secondary damage to the wound, and can be applied to full-thickness scar-free healing, showing excellent therapeutic effects.

[0003] Hydrogels similar to ECM show great potential in wound healing, can maintain a moist environment, provide stable mechanical support for the proliferation of new cells, and promote the exchange of wound substances. Although aqueous polyurethane is a promising biomaterial for tissue engineering immune response, ordinary aqueous polyurethane hydrogels have a hydrated layer on the surface, with a dense and poreless structure, which hinders cell adhesion and growth and is not conducive to the healing of damaged tissues. Summary of the Invention

[0004] One object of the present invention is to provide a hydrogel wound dressing with good hemostatic and wound healing properties simultaneously in view of the above technical problems to be solved.

[0005] Another object of the present invention is to provide a preparation method of the hydrogel wound dressing.

[0006] Still another object of the present invention is to provide the application of the hydrogel wound dressing.

[0007] To achieve the above invention objects, the present invention provides a hydrogel wound dressing for promoting the healing of infectious wounds, which comprises the following raw materials: oxidized methylacrylic acid hyaluronic acid, aqueous polyurethane, polylysine, cannabidiol, neomycin sulfate, 2-borneol.

[0008] Preferably, in the hydrogel, the mass-volume concentration of oxidized methylacrylic acid hyaluronic acid is 3-7%, the mass-volume concentration of aqueous polyurethane is 3-7%, the mass-volume concentration of polylysine is 4-6%, the molar concentration of cannabidiol is 0.5-2 M, the molar concentration of neomycin sulfate is 0.5-2 M, and the molar concentration of 2-borneol is 0.5-2 M.

[0009] Preferably, the molar ratio of cannabidiol, neomycin sulfate, and 2-borneol is (0.5-2):(0.5-2):(0.5-2), and most preferably 1:1:1.

[0010] Preferably, the oxidation degree of oxidized methylacrylic acid hyaluronic acid is 25%-50%.

[0011] Preferably, the solid content of aqueous polyurethane is 10-20%.

[0012] On the other hand, the present invention also provides a preparation method of the hydrogel wound dressing, and the method comprises the following steps: Dissolve oxidized methylacrylic acid hyaluronic acid and aqueous polyurethane in water, add polylysine, sequentially add cannabidiol, neomycin sulfate, and 2-borneol, and finally add a photoinitiator and carry out ultraviolet light irradiation to obtain a hydrogel.

[0013] Preferably, the oxidized methylacrylic acid hyaluronic acid is prepared through the following steps: (1) Prepare a hyaluronic acid solution with a mass-volume concentration of 1%; (2) Add methacrylic anhydride accounting for 1% of the volume of the hyaluronic acid solution, adjust the pH to 8 - 9, and react for 24 hours; (3) Pour the reacted mixed liquid into ice ethanol with a volume 3 to 5 times that of the mixed liquid. Precipitation occurs. Redissolve the precipitate, dialyze it, and freeze-dry it to obtain methacrylic acid hyaluronic acid; (4) Prepare a methacrylic acid hyaluronic acid solution with a mass-volume concentration of 1%. Add sodium periodate accounting for 0.5 - 1% of the mass-volume ratio of the hyaluronic acid solution and continue stirring. Add ethylene glycol accounting for 2% of the volume of the hyaluronic acid solution to terminate the reaction. Dialyze and freeze-dry to obtain oxidized methacrylic acid hyaluronic acid.

[0014] Preferably, the aqueous polyurethane is prepared through the following steps: (1) Take 6 mmol of polyethylene glycol 2000 and 2 mmol of polycaprolactone 2000, dehydrate them under vacuum, react at 110 °C for 2 hours, then cool down to 50 °C and maintain for 30 - 45 min; (2) Add 19.2 mmol of isophorone diisocyanate, stir for 20 min, add 20 μL of catalyst, stir for 20 min, then heat up to 75 °C and react for 2.5 hours; add 6 mmol of chain extender and continue to react for 1.5 - 2 hours; (3) After the temperature drops to 50 °C, add 12 mmol of 2 - hydroxyethyl methacrylate and 3 mmol of triethylamine, continue to react for 21 - 24 hours, and then drop it into 100 - 200 mL of pure water to obtain an aqueous polyurethane with a solid content of 10 - 20%.

[0015] Preferably, the cannabidiol solution is an ethanol solution of cannabidiol with a molar concentration of 0.5 - 2 M.

[0016] Preferably, the mass-volume concentration of the aqueous solution of polylysine is 4% - 6%.

[0017] Preferably, the neomycin sulfate solution is an aqueous solution of neomycin sulfate with a molar concentration of 0.5 - 2 M.

[0018] Preferably, the borneol solution is an ethanol solution of borneol with a molar concentration of 0.5 - 2 M.

[0019] Preferably, the photoinitiator is an aqueous solution of 2 - hydroxy - 4'-(2 - hydroxyethoxy)-2 - methylpropiophenone (I2959) with a mass-volume concentration of 1%.

[0020] Preferably, the molecular weight of the hyaluronic acid is 150,000 - 200,000.

[0021] On the other hand, the present invention also provides an application of the hydrogel wound dressing in the preparation of a product for repairing infectious wounds.

[0022] In order to accelerate wound healing and avoid chronic inflammation, the present invention covalently crosslinks aqueous polyurethane with oxidized methacrylic acid hyaluronic acid (OHAMA), and adds the natural antibacterial polymer material polylysine (PL) to construct a three-dimensional porous oxidized methacrylic acid hyaluronic acid-aqueous polyurethane-polylysine (OHAMA-PU-PL) hydrogel with innate immune regulation ability. At the same time, it loads cannabidiol (CBD), neomycin sulfate (NS) and 2-borneol (2-B) to produce analgesic, anti-inflammatory and antibacterial effects. The wound dressing of the present invention has a microporous structure, good biocompatibility and biodegradability, and can be used to promote wound healing. In addition, the preparation method of the hydrogel dressing of the present invention is simple, and the reaction can be completed without any additional solvents and special instruments, providing a new idea for the rapid production and preparation of natural polymer hydrogels, successfully solving the problem between complex functions and simple preparation in the field of wound dressings. The obtained hydrogel dressing is suitable for simultaneously having good wound healing performance, which can reduce wound surface infection, promote cell proliferation and wound healing. Description of the Drawings

[0023] Figure 1 Shows the water absorption rates of different hydrogels at different time points.

[0024] Figure 2 Shows the viscosities of different hydrogels. (A) Viscosity in the frequency range of 0.1 - 10 Hz; (B) Viscosity with shear stress of 0.1 - 100%.

[0025] Figure 3 Shows the adhesion strength of different hydrogels on pig skin.

[0026] Figure 4 Shows the change in pH value of the hydrogel extract.

[0027] Figure 5 Shows the drug release of cannabidiol over time in Example 13.

[0028] Figure 6 Shows the colony images after culturing different samples for 24 hours.

[0029] Figure 7 Shows the results of the cytotoxicity experiment. (A) Images of different samples after culturing with blood cells and the hemolysis rate; (B) Cell viability statistics after treating different samples with CCK8 after culturing for 24 hours; (C) Live-dead staining images of different samples after culturing with 3T3 cells.

[0030] Figure 8The gene expression levels and results of the cell scratch assay after treating RAW 246.7 with the hydrogel extract are shown. (A) Gene expression levels; (B) Migration of 3T3 cells and cell scratch healing rate after 24 hours of culture.

[0031] Figure 9 The healing conditions, healing rates, and body weight changes of the back wounds of mice over time are shown. (A) Healing conditions; (B) Healing rates; (C) Body weight changes of mice during the treatment period. The values are mean ± standard deviation (SD) (n = 3), *p < 0.05, **p < 0.01, ***p < 0.001.

[0032] Figure 10 The results of analyzing skin tissue sections of different treatment groups on the 0th, 5th, and 10th days of treatment using H&E and Masson staining are shown. Detailed implementation manners

[0033] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0034] Example 1 Prepare oxidized methacrylic acid hyaluronic acid - waterborne polyurethane - polylysine (OHAMA - PU - PL) hydrogel according to the following steps: 1. Prepare oxidized methacrylic acid hyaluronic acid (OHAMA) (1) Weigh 1.0 g of hyaluronic acid (HA) (the molecular weight can be 150,000 to 200,000, and hyaluronic acid with a molecular weight of 150,000 is used in this example), add 100 mL of pure water, and magnetically stir for 2 hours to completely dissolve and defoam it to obtain a hyaluronic acid solution with a mass - volume concentration of 1% (w / v%, g / mL).

[0035] (2) Add 10 mL (1% of the volume of the hyaluronic acid solution) of methacrylic anhydride (MAA), and then adjust the pH to 8 with a 10M NaOH aqueous solution and react for 24 hours.

[0036] (3) Pour the reacted mixed liquid into 300 mL of ice ethanol (3 times the volume of the hyaluronic acid solution), and a precipitate appears. Dissolve the precipitate in 100 mL of pure water and dialyze it with a dialysis bag (Da = 3500) for 3 days, then freeze-dry to obtain hyaluronic acid methacrylate (HAMA).

[0037] (4) Weigh 1.0 g of HAMA, add 100 mL of pure water, and stir magnetically until it is completely dissolved. Then add 0.5 g of sodium periodate (NaIO4) and continue stirring for 4 hours. After that, add 2 mL of ethylene glycol to terminate the reaction, dialyze it with a dialysis bag (Da = 3500) for 3 days, and then freeze-dry to obtain oxidized hyaluronic acid methacrylate (OHAMA) with an oxidation degree of 50% (the oxidation degree can be 25% to 50%, and the addition amount of sodium periodate can be adjusted accordingly according to the required oxidation degree). Store it at -20 °C after drying.

[0038] 2. Preparation of aqueous polyurethane (PU) (1) Take 6 mmol of polyethylene glycol 2000 (PEG 2000) and 2 mmol of polycaprolactone 2000 (PCL 2000) in a three-necked flask, dehydrate under vacuum, react at 110 °C for 2 hours, then cool down to 50 °C and maintain for 40 min.

[0039] (2) Add 19.2 mmol of isophorone diisocyanate (IPDI), stir for 20 min, add 20 μL of dibutyltin dilaurate (DBTDL), stir for 20 min, then heat up to 75 °C and react for 2.5 hours. Add 6 mmol of chain extender 2,2-bis(hydroxymethyl)propionic acid (DMPA) and continue to react for 1.5 hours.

[0040] (3) After the temperature drops to 50 °C, add 12 mmol of 2-hydroxyethyl methacrylate (HEMA) and 3 mmol of triethylamine, continue to react for 21 hours, and then drop it into 100 mL of pure water (stir with a cantilever stirrer at 1000 rpm / min for 1 hour) to obtain an aqueous polyurethane (PU) with a solid content of 20%. The solid content of the aqueous polyurethane applicable to the present invention can be 10% to 20%, and can be adjusted by changing the amount of pure water added.

[0041] 3. Preparation of 6% (w / v%, g / mL) oxidized hyaluronic acid methacrylate-aqueous polyurethane (OHAMA-PU) solution: Weigh 240 mg of oxidized hyaluronic acid methacrylate solid and dissolve it with 4 mL of water and 1 mL of aqueous polyurethane (solid content 20%) for standby.

[0042] 4. Preparation of 4% (w / v%, g / mL) polylysine (PL) solution: Weigh 120 mg of polylysine solid and place it in a vial. Dissolve it with 3 mL of pure water, and adjust the pH to 8 by adding 1 M NaOH aqueous solution for standby.

[0043] 5. Preparation of hydrogel Put 1 mL of 6% OHAMA-PU solution in a vial, add 200 μL of 4% polylysine solution, stir to dissolve it, then add 10 μL of 1% photoinitiator I2959 (photoinitiator 2959, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone), and irradiate with ultraviolet light for 1 hour to observe the gel formation.

[0044] Example 2 The embodiment of the present invention provides a hydrogel. The only difference in the preparation method of the hydrogel from that of Example 1 lies in the concentration of the OHAMA-PU solution in step (3), that is, 4% OHAMA-PU solution is used (200 mg of oxidized methacrylic acid hyaluronic acid solid is placed in a plate and dissolved in 4 mL of water and 1 mL of aqueous polyurethane).

[0045] Example 3 The embodiment of the present invention provides a hydrogel. The only difference in the preparation method of the hydrogel from that of Example 1 lies in the concentration of the OHAMA-PU solution in step (3), that is, 5% OHAMA-PU solution is used (250 mg of oxidized methacrylic acid hyaluronic acid solid is placed in a plate and dissolved in 4 mL of water and 1 mL of aqueous polyurethane).

[0046] Example 4 The embodiment of the present invention provides a hydrogel. The only difference in the preparation method of the hydrogel from that of Example 1 lies in the concentration of the OHAMA-PU solution in step (3), that is, 6% OHAMA-PU solution is used (300 mg of oxidized methacrylic acid hyaluronic acid solid is placed in a plate and dissolved in 4 mL of water and 1 mL of aqueous polyurethane).

[0047] Example 5 The embodiment of the present invention provides a hydrogel. The only difference in the preparation method of the hydrogel from that of Example 1 lies in the concentration of the OHAMA-PU solution in step (3), that is, 7% OHAMA-PU solution is used (350 mg of oxidized methacrylic acid hyaluronic acid solid is placed in a plate and dissolved in 4 mL of water and 1 mL of aqueous polyurethane).

[0048] Example 6 The embodiment of the present invention provides a hydrogel. The only difference in the preparation method of the hydrogel from that of Example 1 lies in that the light irradiation time in step (5) is 30 minutes.

[0049] Example 7 An embodiment of the present invention provides a hydrogel. The only difference between the preparation method of this hydrogel and that of Example 1 is that the light exposure time in step (5) is 2 hours.

[0050] Example 8 An embodiment of the present invention provides a hydrogel. The only difference between the preparation method of this hydrogel and that of Example 1 is that the light exposure time in step (5) is 3 hours.

[0051] Example 9 An embodiment of the present invention provides a hydrogel. The only difference between the preparation method of this hydrogel and that of Example 1 is that the light exposure time in step (5) is 4 hours.

[0052] Example 10 An embodiment of the present invention provides a hydrogel. The only difference between the preparation method of this hydrogel and that of Example 1 is that the light exposure time in step (5) is 5 hours.

[0053] Example 11 A novel hemostatic hydrogel is prepared as follows: (1) Preparation of 6% (w / v%, g / mL) OHAMA-PU solution: Weigh 240 mg of oxidized hyaluronic acid methacrylate solid and place it in a flat plate. Dissolve it with 4 mL of water and 1 mL of aqueous polyurethane for later use.

[0054] (2) Preparation of 4% (w / v%, g / mL) polylysine solution: Weigh 120 mg of polylysine solid and place it in a vial. Dissolve it with 3 mL of pure water for later use.

[0055] (3) Preparation of 1M (1 mol / L) cannabidiol solution: Weigh 315 mg of CBD solid and place it in a vial. Dissolve it with 1 mL of ethanol for later use.

[0056] (4) Preparation of 1% (w / v%, g / mL) I2959 solution: Weigh 10 mg of I2959 solid and place it in a vial. Dissolve it with 1 mL of water for later use.

[0057] (5) Add 1 mL of 6% OHAMA-PU solution to 200 μL of 4% polylysine solution. After mixing, sequentially add 20 μL of 1M cannabidiol, 20 μL of 1M neomycin sulfate, 20 μL of 1M 2-menthol and continue to mix. Finally, add 100 μL of 1% I2959 solution. After mixing, transfer the sol to a mold and irradiate it under ultraviolet light for 1 hour. Observe the gel formation to obtain a hydrogel wound dressing.

[0058] Example 12 A novel hemostatic hydrogel is prepared as follows: (1) Preparation of 6% (w / v%, g / mL) OHAMA-PU solution: Weigh 240 mg of oxidized hyaluronic acid methacrylate solid and place it in a flat plate. Dissolve it with 4 mL of water and 1 mL of aqueous polyurethane for later use.

[0059] (2) Preparation of 4% (w / v%, g / mL) polylysine solution: Weigh 120 mg of polylysine solid and place it in a vial. Dissolve it with 3 mL of pure water for later use.

[0060] (3) Preparation of 1M (1 mol / L) cannabidiol solution: Weigh 315 mg of CBD solid and place it in a vial. Dissolve it with 1 mL of ethanol for later use.

[0061] (4) Preparation of 1M (1 mol / L) borneol mixed solution: Weigh 154 mg of borneol and dissolve it in 1 mL of absolute ethanol.

[0062] (5) Preparation of 1% (w / v%, g / mL) I2959 solution: Weigh 10 mg of I2959 solid and place it in a vial. Dissolve it with 1 mL of water for later use.

[0063] (6) Add 1 mL of 6% OHAMA-PU solution to 200 μL of 4% polylysine solution. After mixing, sequentially add 20 μL of 1M cannabidiol, 20 μL of 1M neomycin sulfate, and 20 μL of 1M borneol, and continue to mix. Finally, add 100 μL of 1% I2959 solution. After mixing, transfer the sol to a mold and irradiate it under an ultraviolet lamp for 1 hour. Observe the gel formation to obtain a hydrogel wound dressing.

[0064] Example 13 A novel hemostatic hydrogel, and its preparation steps are as follows: (1) Preparation of 6% (w / v%, g / mL) OHAMA-PU solution: Weigh 240 mg of oxidized hyaluronic acid methacrylate solid and place it in a flat plate. Dissolve it with 4 mL of water and 1 mL of aqueous polyurethane for later use.

[0065] (2) Preparation of 4% (w / v%, g / mL) polylysine solution: Weigh 120 mg of polylysine solid and place it in a vial. Dissolve it with 3 mL of pure water for later use.

[0066] (3) Preparation of 1M (1 mol / L) cannabidiol solution: Weigh 315 mg of CBD solid and place it in a vial. Dissolve it with 1 mL of ethanol for later use.

[0067] (4) Preparation of 1M (1 mol / L) borneol mixed solution: Weigh 154 mg of borneol and dissolve it in 1 mL of absolute ethanol.

[0068] (5) Preparation of 1 M (1 mol / L) neomycin sulfate solution: Weigh 712 mg of neomycin sulfate (NS) and dissolve it in 1 mL of pure water.

[0069] (6) Preparation of 1% (w / v%, g / mL) I2959 solution: Weigh 10 mg of solid I2959 and place it in a vial, then dissolve it with 1 mL of water for later use.

[0070] (7) Add 1 mL of 6% OHAMA-PU solution to 200 μL of 4% polylysine solution, mix well, then sequentially add 20 μL of 1 M cannabidiol, 20 μL of 1 M neomycin sulfate, and 20 μL of 1 M 2-menthol, and continue to mix well. Finally, add 100 μL of 1% I2959 solution, mix well, transfer the sol to a mold, and irradiate it under ultraviolet light for 1 hour to observe the gel formation. A hydrogel wound dressing is obtained.

[0071] In the present invention, first, a stable hydrogel basic framework is obtained by covalent cross-linking. Using the Schiff base reaction, polylysine is introduced into the hydrogel network, and drug molecules such as cannabidiol, neomycin sulfate, and 2-menthol are added. The hydrogen bonds formed between amino groups and hydroxyl groups are used to strengthen the cross-linking strength of the hydrogel three-dimensional network, and a patch-type hydrogel product that can be applied to promote wound healing is obtained.

[0072] The effect examples of the present invention verify the antibacterial properties and biocompatibility of the hydrogel dressings prepared in Example 1 and Example 13, which specifically include the following parts: Performance testing The antibacterial property and cytotoxicity test of the hydrogel refer to GB / B 31402-2015 and YY / T 1911-2023 respectively From Example 1-13, as shown in Table 1, with the changes in the OHAMA-PU solution and PL concentration, the gel formation of the hydrogel will also change accordingly; among them, the influencing factor also includes the light irradiation time; through comparison and final evaluation, it is confirmed that when the OHAMA-PU concentration is 6%, the PL concentration is 4%, and the light irradiation time is 1 hour, the gel formation is the best.

[0073] Therefore, for subsequent performance research, the hydrogels in Example 1 and Example 13 will be used for determination.

[0074] Table 1: Comparison of the gelation time of the hydrogels in each example

[0075] By measuring the change in the water absorption rate of the freeze-dried hydrogel over time, from Figure 1It can be seen that the freeze-dried samples of the hydrogels in Example 1 and Example 13 have a particularly fast water absorption rate. They rapidly swell to about 5 times their dry weight within 15 minutes and reach a water swelling equilibrium of about 20 times at 60 minutes.

[0076] When the storage modulus (G′) is greater than the loss modulus (G′′), the hydrogel is in a gel state. As Figure 2 shown, after the hydrogel undergoes gelation, as the angular frequency and shear stress increase, G′ is always greater than G′′, indicating that the hydrogel can stably appear in a gel state ( Figure 3 , A, B). This shows that the hydrogel has good mechanical properties to maintain its convenience and integrity. Adhesion performance is very important for wounds. Good adhesion can ensure that the formed gel firmly adheres to the surface of the bleeding tissue without falling off.

[0077] Adhesion tests were carried out on different samples. From Figure 3 it can be seen that the OHAMA-PU-PL hydrogel of Example 1 has good self-adaptability and tissue adhesion characteristics to pig skin; and the adhesion reaches 1.38 kPa.

[0078] During the wound treatment stage, the hydrogel affects the wound healing ability due to the change of skin environmental pH. By measuring the change of pH over time of the OHAMA-PU-PL (Example 1) and OHAMA-PU-PL-CBD-NS-(2-B) (Example 13) hydrogels in physiological saline and buffer solution PBS (7.4), it is found that the pH of both hydrogels gradually decreases with the passage of time ( Figure 4 ). This may be because of the influence of the acidic PL released in the hydrogel system, which will help improve the antibacterial ability of infectious wounds. As Figure 5 can be seen, the drug cannabidiol (CBD) in the hydrogel component can be continuously and stably released in a physiological saline environment, which will help the drug continuously reach the wound and inhibit the emergence of bacterial inflammation.

[0079] The antibacterial hydrogel has the ability to inhibit bacterial growth. Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were selected as bacterial models, and the antibacterial effect of the hydrogel was explored by the OD value counting method (Table 2; Figure 6 ) It can be found that the OHAMA-PU-PL hydrogel of Example 1 has certain antibacterial properties, and the OHAMA-PU-PL-CBD-NS-(2-B) of Example 13 has good antibacterial properties against both model bacteria due to the introduction of antibiotics.

[0080] Table 2. OD600 values of Staphylococcus aureus and Escherichia coli after culturing different samples for 24 hours

[0081] In the cytotoxicity experiment, it was observed that the test substance had a significant effect on cell growth. Evaluated by the CCK-8 colorimetric method, when the concentration of the test substance was at different dilution concentrations, the cell survival rate reached about 100%, indicating that at this concentration, the substance had weak cytotoxicity ( Figure 7 , B, C). The experimental results suggest that the hydrogel extract has no obvious cytotoxicity at different dilution concentrations. In the hemolysis experiment, it can be found that the hydrogel has good blood compatibility ( Figure 7 , A).

[0082] Subsequently, the gene expression levels of macrophages (RAW 246.7) were detected by fluorescence quantitative PCR, and it was found that the hydrogel groups (Example 1, Example 13) promoted the activation of RAW 246.7 towards M1, which was beneficial to increasing the early inflammatory level in wound healing, thereby enhancing the bactericidal ability of the body ( Figure 8 , A).

[0083] In the cell scratch experiment, it was found that the hydrogel groups (Example 1, Example 11, Example 12, Example 13) all had the function of promoting cell migration ( Figure 8 , B), which would help improve the wound healing ability.

[0084] To determine whether the hydrogel was helpful for wound healing, the hydrogel was applied to partial-thickness wounds of mice ( Figure 9 , A). After 10 days of treatment, in the control group (3M dressing group), obvious suppuration occurred on the third day and continued until the 7th day. Regular and inconsistent red scars also appeared around the wound on the skin surface on the 10th day, and the wound healing rate was 65.76%. This was because there was pus around the wound, which hindered wound healing. Compared with the untreated group, there were no signs of suppurative infection in the hydrogel group during the treatment stage; the healing rates were also significantly increased to 89.62 ± 3.30% (p < 0.01) and 85.68 ± 1.25% (p < 0.01), and the healing was obvious ( Figure 9 , A, B). In addition, and in the OHAMA-PU-PL group (Example 1), there was a residue of the hydrogel film on the skin surface on the fifth day of treatment; debriding was likely to cause secondary injury to the wound. Fortunately, over time, the film on the wound surface could be absorbed by itself. During the treatment period, there was no obvious change in the body weight of the mice in the control group (3M) and the drug-added group (Example 13) ( Figure 9, C); The body weights of the mice in the OHAMA-PU-PL group (Example 1) showed significantly enhanced changes on the third and fifth days, which was consistent with the trend of wound healing. This may be because the alleviation of wound healing helps to increase the motivation of the mice to eat every day. In summary, both the OHAMA-PU-PL group and the medicated group can effectively treat infectious wounds.

[0085] Figure 10 The results of analyzing skin tissue sections of different treatment groups on the 0th, 5th, and 10th days of treatment using H&E and Masson staining are shown. Bacterial infection causes severe inflammatory reactions at the wound site, leading to the infiltration of inflammatory cells. Therefore, H&E staining is often used to observe the inflammatory state at the wound site, and its inflammatory cells usually show the characteristic of a large nuclear specific gravity. Figure 10 It can be seen that there were still a large number of inflammatory cell infiltrations in the control group on the 5th day, but the inflammatory cell infiltrations in Example 1 and Example 13 were relatively less, as indicated by the blue arrows. On the 10th day, the epidermal layers in the groups of Example 1 and Example 13 were basically formed, and almost no inflammatory cell infiltration was seen, showing a similar state to the tissue section staining of healthy mice. There were still some inflammatory cell infiltrations in the blank control group. The formation of collagen plays a key role in the wound healing process, which can promote cell migration and serve as the basis for extracellular matrix deposition during the proliferation stage of wound healing. Masson staining can be used to evaluate the formation of collagen, and its collagen is stained blue. Figure 10 As shown, no obvious collagen deposition was seen in the skin tissue of the control group after 5 days of healing. However, the collagen depositions in the gel groups of Example 1 and Example 13 were relatively high. On the 10th day, the epidermis and dermis layers of each group were basically formed, and a large amount of collagen was deposited. Moreover, the number of hair follicles in the treatment group was higher, and the collagen fiber structure was stacked orderly, indicating that its treatment method has a positive effect on healing. These phenomena indicate that this material is beneficial to reducing the generation of inflammation and scars and accelerating healing.

Claims

1. A hydrogel wound dressing for promoting the healing of infectious wounds, characterized in that It includes the following raw materials: oxidized methylacrylic acid hyaluronic acid, waterborne polyurethane, polylysine, cannabidiol, neomycin sulfate, and 2-bornanol.

2. The hydrogel wound dressing according to claim 1, wherein In the hydrogel, the mass-volume concentration of oxidized methylacrylic acid hyaluronic acid is 3-7%, the mass-volume concentration of waterborne polyurethane is 3-7%, the mass-volume concentration of polylysine is 4-6%, the molar concentration of cannabidiol is 0.5-2 M, the molar concentration of neomycin sulfate is 0.5-2 M, and the molar concentration of 2-bornanol is 0.5-2 M.

3. The hydrogel wound dressing according to claim 1, wherein The molar ratio of cannabidiol, neomycin sulfate, and 2-bornanol is (0.5-2):(0.5-2):(0.5-2).

4. The hydrogel wound dressing according to claim 1, wherein The oxidation degree of oxidized methylacrylic acid hyaluronic acid is 25%-50%.

5. The hydrogel wound dressing according to claim 1, characterized in that, The solid content of waterborne polyurethane is 10-20%.

6. The preparation method of the hydrogel wound dressing according to any one of claims 1 to 5, characterized in that The method includes the following steps: Dissolve oxidized methylacrylic acid hyaluronic acid and waterborne polyurethane in water, add polylysine, sequentially add cannabidiol, neomycin sulfate, and 2-bornanol, and finally add a photoinitiator, and perform ultraviolet light irradiation to obtain the hydrogel.

7. The preparation method according to claim 6, characterized in that, The oxidized methylacrylic acid hyaluronic acid is prepared through the following steps: (1) Prepare a 1% (mass-volume) hyaluronic acid solution; (2) Add 1% (by volume) of methacrylic anhydride to the hyaluronic acid solution, adjust the pH to 8-9, and react for 24 hours; (3) Pour the reacted mixed liquid into 3 to 5 times its volume of ice ethanol, precipitate appears, redissolve the precipitate and dialyze, and freeze-dry to obtain methylacrylic acid hyaluronic acid; (4) Prepare a 1% (mass-volume) methylacrylic acid hyaluronic acid solution, add 0.5-1% (by mass-volume) of sodium periodate to the hyaluronic acid solution and continue stirring, add 2% (by volume) of ethylene glycol to the hyaluronic acid solution to terminate the reaction, dialyze, and freeze-dry to obtain oxidized methylacrylic acid hyaluronic acid.

8. The preparation method according to claim 6, characterized in that, The waterborne polyurethane is prepared through the following steps: (1) Take 6 mmol of polyethylene glycol 2000 and 2 mmol of polycaprolactone 2000, dehydrate under vacuum, react at 110°C for 2 hours, then cool down to 50°C and maintain for 30-45 min; (2) Add 19.2 mmol of isophorone diisocyanate, stir for 20 min, add 20 μL of catalyst, stir for 20 min, then raise the temperature to 75°C and react for 2.5 hours; add 6 mmol of chain extender and continue to react for 1.5-2 hours; (3) After the temperature drops to 50°C, add 12 mmol of 2-hydroxyethyl methacrylate and 3 mmol of triethylamine, continue to react for 21-24 hours, and then drop it into 100-200 mL of pure water to obtain a waterborne polyurethane with a solid content of 10-20%.

9. The preparation method according to claim 6, characterized in that, The molecular weight of hyaluronic acid in the hydrogel is 150,000-200,000.

10. Use of the hydrogel wound dressing according to any one of claims 1 to 5 in the preparation of a product for repairing infectious wounds.

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