An antibacterial and anti - pyroptosis double - layer microneedle dressing and its preparation method and application

Abstract

The present invention relates to the technical field of biomedical materials, and provides an antibacterial and anti-pyroptosis double-layer microneedle dressing, a preparation method thereof, and an application thereof. A preparation method of an antibacterial and anti-pyroptosis double-layer microneedle dressing comprises the following steps: mixing a polymethacrylamide chitosan solution with a 3-hydroxybutyric acid solution, adding the mixture into a silica gel microneedle mold, and curing to form microneedle tips; coating polyvinyl alcohol at the bottom of the silica gel microneedle mold with formed microneedle tips, curing to form microneedle bases, demolding, and drying to obtain the antibacterial and anti-pyroptosis double-layer microneedle dressing. The antibacterial and anti-pyroptosis double-layer microneedle dressing for skin infected wounds prepared by the present invention has antibacterial properties, can reduce the adverse effects brought by the rapid proliferation and diffusion of bacteria in the infected wounds, and can promote the healing of wounds faster.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and particularly relates to an antibacterial and anti-pyroptosis double-layer microneedle dressing, a preparation method thereof, and an application thereof. Background Art

[0002] Large-area infected skin wounds are common clinical traumatic diseases. If not treated in a timely and effective manner, bacteria are likely to quickly enter the deep subcutaneous tissues or the blood, causing serious complications such as necrotizing fasciitis and sepsis, resulting in long-term hospitalization, amputation, and even endangering the life of the patient.

[0003] Current treatment strategies mainly focus on the systemic application of broad-spectrum antibiotics to prevent the occurrence of systemic complications. However, the long-term systemic application of broad-spectrum antibiotics lacks specificity, and due to the low drug concentration at the infected wound site, the ability to inhibit bacterial growth is limited, and drug resistance is easily generated, leading to the emergence of drug-resistant strains. Therefore, polyacrylamide chitosan has become a new emerging antibacterial component in clinical practice due to its advantages of local application, broad-spectrum antibacterial activity, and low tendency to produce drug-resistant strains.

[0004] Another serious clinical problem is that even after the infection is controlled in large-area infected skin, chronic inflammation still exists in the tissue, resulting in non-healing wounds. Recent studies have shown that after bacterial infection, the NLRP3 inflammasome in macrophages in the tissue is activated stressfully, initiating the process of pyroptosis. The process of pyroptosis leads to the synthesis of a large amount of inflammatory factors in cells, which are released into the tissue along with cell rupture and death, manifested as an explosive increase in inflammation in the tissue or the formation of chronic inflammation that is difficult to heal in a cycle, that is, the key mechanism for the difficult healing of infected wounds. Regulating pyroptosis has become a new idea for developing therapeutic drugs to solve the problem of infectious skin trauma. Recent sensational studies have confirmed that 3-hydroxybutyric acid (3HB), a widely existing metabolite of fat metabolism in the human body, can specifically and significantly inhibit the NLRP3 inflammasome and reduce macrophage pyroptosis. However, whether 3HB can promote the healing of bacterial-infected skin wounds is currently unknown. In addition, how to effectively combine 3HB and polyacrylamide chitosan and maintain an effective concentration in the tissue for a long time is the key point for the treatment of infected wounds.

[0005] When the microneedle patch drug delivery system is applied, a large number of micro-sized drug-loaded gels can be formed in the skin mucosa. Due to its tiny size, the tip of the microneedle only pierces the skin or mucosal surface layer, without stimulating the nerve endings under the skin, so it will not cause additional pain to the patient. Currently, the microneedle patch drug delivery system has become a widely used minimally invasive, painless, uniformly sustained-release, and highly efficient transdermal therapy. In the wound repair of the skin or mucosa, the microneedle patch drug delivery system can improve the utilization rate of drugs, increase the contact area between the dressing drug and the wound, and thus better play the repair effect.

[0006] Therefore, the preparation of a sustained-release material with ideal functions, unique structure, antibacterial and anti-pyroptosis effects is of great significance and has great clinical popularization value for the treatment of infected wounds. Summary of the Invention

[0007] The purpose of the present invention is to provide an antibacterial and anti-pyroptosis double-layer microneedle dressing and its preparation method and application, in order to solve the clinical problems of serious complications such as necrotizing fasciitis and even sepsis caused by the spread of bacterial infections that are prone to occur during the treatment of existing skin infections, low bioavailability of oral antibiotic treatment and the easy generation of drug-resistant strains, and the chronic inflammation caused by macrophage pyroptosis in tissues persists, resulting in the non-healing of infected wounds.

[0008] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a preparation method of an antibacterial and anti-pyroptosis double-layer microneedle dressing. The method includes the following steps:

[0010] (1) Mix the polymethacrylamide chitosan solution with the 3-hydroxybutyric acid solution, add it to a silica gel microneedle mold, and cure to form the microneedle tip.

[0011] (2) Coat polyvinyl alcohol at the bottom of the silica gel microneedle mold where the microneedle tip is formed, cure to form the microneedle base, demold, and dry to obtain the antibacterial and anti-pyroptosis double-layer microneedle dressing.

[0012] Preferably, the molecular weight of the polymethacrylamide chitosan in step (1) is 50-90KDa; the concentration of the polymethacrylamide chitosan solution is 2-10% (w / v); the concentration of the 3-hydroxybutyric acid solution is 10-40 mM, and the 3-hydroxybutyric acid can also be replaced by 3-hydroxybutyrate; the volume ratio of the polymethacrylamide chitosan solution to the 3-hydroxybutyric acid solution is 0.95-1.05:0.95-1.05.

[0013] Preferably, the curing in step (1) is photocuring, the excitation light wavelength of the photocuring is 365nm-405nm, and the light irradiation time of the photocuring is 30s-5min.

[0014] Preferably, the blunt end diameter of the microneedle tip is 300-600μm; the length of the microneedle tip is 800-150μm.

[0015] Preferably, the curing in step (2) is dry curing, the temperature of the dry curing is 34-40°C; the time of the dry curing is 5-7h.

[0016] Preferably, the thickness of the microneedle base in step (2) is 0.1-5mm.

[0017] Preferably, the drying in step (2) is freeze-drying, and pre-freezing is carried out before freeze-drying; the temperature of pre-freezing is -120 to -60 °C; the time of pre-freezing is 15 to 45 min; the temperature of freeze-drying is -60 °C to -40 °C; the time of freeze-drying is 8 to 16 h.

[0018] The present invention provides an antibacterial and anti-pyroptosis double-layer microneedle dressing.

[0019] The present invention also provides an application of the antibacterial and anti-pyroptosis double-layer microneedle dressing in the preparation of a skin soft tissue infection wound repair material or a drug.

[0020] The antibacterial and anti-pyroptosis microneedle patch for treating skin infections and wounds of the present invention is composed of a substrate and microneedles arrayed on one side of the substrate. The drug-loaded microneedles are conical or pyramidal. The matrix material is antibacterial polymethacrylamide chitosan loaded with 3-hydroxybutyric acid having an anti-pyroptosis effect. The base is formed by curing polyvinyl alcohol and can be rapidly dissolved at 37 °C. The antibacterial and anti-pyroptosis microneedle patch can be attached to the skin wound. The base rapidly dissolves and falls off after contacting the body temperature; the conical microneedles arranged in an array break away from the base and remain in the skin tissue. Polymethacrylamide chitosan has an initial antibacterial effect to reduce the amplification and invasion of bacteria in the tissue; as polymethacrylamide chitosan swells and degrades, the loaded 3HB is gradually released, which has the effect of inhibiting cell pyroptosis and reducing the inflammatory level in the tissue, thereby accelerating the wound healing process.

[0021] The antibacterial and anti-pyroptosis double-layer microneedle dressing provided by the present invention has good in vitro cell compatibility and in vivo biosafety; in vitro experiments show that it has a significant inhibitory effect on macrophage pyroptosis caused by Staphylococcus aureus and has a good inhibitory effect on Staphylococcus aureus; in vivo experiments show that it has a significant effect on promoting the healing of skin wounds of mice infected with Staphylococcus aureus and has a significant effect on inhibiting cell pyroptosis in the skin wounds of mice infected with Staphylococcus aureus and reducing chronic inflammation, showing its great application potential in skin infection wounds.

[0022] The antibacterial and anti-pyroptosis double-layer microneedle dressing provided by the present invention can be used for the initial treatment of large-area infectious wounds of skin soft tissues; the presence of the base ensures that the tip of the needle can be completely inserted into the skin tissue during use; at the same time, the rapid solubility of the base in a 37 °C environment ensures the clinical treatment principle of keeping the infected wound breathable and not closed; the components of 3HB and polymethacrylamide chitosan at the tip of the needle can inhibit bacteria in the initial stage and reduce macrophage pyroptosis in the tissue, and are not likely to produce drug-resistant strains, and are suitable for various bacterial infections.

[0023] The antibacterial and anti - pyroptosis double - layer microneedle dressing for skin infection wounds provided by the present invention has good mechanical properties, and its mechanical strength is mainly provided by polyacrylamide - chitosan gel. In vitro puncture experiments show that the antibacterial and anti - pyroptosis double - layer microneedle dressing provided by the present invention can penetrate the intact skin structure of rats and has the application potential of delivering drugs to subcutaneous basal cells and nearby connective tissues.

[0024] The matrix material of the antibacterial and anti - pyroptosis double - layer microneedle dressing for skin infection wounds described in the present invention has antibacterial properties, which can reduce the adverse effects brought by the rapid proliferation and diffusion of bacteria in the infected wound and promote wound healing faster.

[0025] The present invention also provides a preparation method of the above - mentioned antibacterial and anti - pyroptosis double - layer microneedle dressing for skin infection wounds. The operation of this method is simple, the conditions are mild, and there is no need for high temperature, which is beneficial to protecting the activity of the loaded drugs. At the same time, the antibacterial and anti - pyroptosis double - layer microneedle dressing described in the present invention can load a variety of different drugs other than 3HB. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for description in the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0027] Figure 1 It is a physical picture with the tip of the antibacterial and anti - pyroptosis double - layer microneedle dressing of Example 1 facing upward;

[0028] Figure 2 It is a scanning electron microscope structure diagram with the tip of the antibacterial and anti - pyroptosis double - layer microneedle dressing prepared in Example 1 facing upward; (scale 1mm, magnification 30 times);

[0029] Figure 3 It is the cell proliferation of mouse bone marrow mesenchymal stem cells cultured on different microneedle dressings and in a blank environment for 1, 4, and 7 days in Experimental Example 1;

[0030] Figure 4 It is the in vitro transdermal experiment of the antibacterial and anti - pyroptosis double - layer microneedle dressing in Experimental Example 2. Among them, Figure (a) is the general observation picture of the microneedles puncturing the intact skin on the back of the mouse, and Figure (b) is the hematoxylin - eosin staining picture of the skin tissue at the microneedle puncture site of the mouse after the base is dissolved;

[0031] Figure 5 It is the antibacterial experimental results of different dressings on Staphylococcus aureus in Experimental Example 3;

[0032] Figure 6The process of establishing a model for the infectious wound on the back skin of mice in Experimental Example 4;

[0033] Figure 7 Pictorial view of the healing effect observation of different dressings on the infectious wound of mice skin for 3 / 5 / 7 / 9 days in Experimental Example 4.

[0034] Figure 8 Healing results of different dressings on the infectious wound of mice skin for 3 / 5 / 7 / 9 days in Experimental Example 4. Detailed implementation manners

[0035] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0036] Embodiment 1

[0037] A preparation method of an antibacterial and anti - pyroptosis double - layer microneedle dressing, comprising the following steps:

[0038] Dissolve polyacrylamide - chitosan (molecular weight 70KDa) and 3 - hydroxybutyric acid in water respectively to obtain a polyacrylamide - chitosan solution with a concentration of 5% (w / v) and a 3 - hydroxybutyric acid solution with a concentration of 20 mM; mix the polyacrylamide - chitosan solution and the 3 - hydroxybutyric acid solution in a volume ratio of 1:1, add 200 μL of the mixed liquid into a silica microneedle mold, centrifuge at 3000 rpm for 5 min to allow the solution to fully penetrate into the mold, then evacuate the microneedle mold, and keep the mold at a negative pressure of - 0.7 MPa during evacuation, and irradiate for 3 min at an excitation light wavelength of 405 nm for curing to obtain microneedle tips with a blunt - end diameter of 500 μm and a tip length of 1200 μm, as Figure 1 shown (photographed with a macro lens of a Canon camera at room temperature);

[0039] Coat polyvinyl alcohol at the bottom of the silica microneedle mold forming the microneedle tips, dry in an oven at 37 °C for 6 h to form a 2 - mm - thick microneedle base, after demolding, pre - freeze at - 80 °C for 30 min, and then freeze - dry at - 50 °C for 12 h to obtain the antibacterial and anti - pyroptosis double - layer microneedle dressing, and the electron microscope scanning image is as Figure 2 shown.

[0040] Embodiment 2

[0041] A preparation method of an antibacterial and anti - pyroptosis double - layer microneedle dressing, comprising the following steps:

[0042] Dissolve chitosan polymethacrylamide (molecular weight 50KDa) and 3-hydroxybutyric acid in water respectively to obtain a chitosan polymethacrylamide solution with a concentration of 2% (w / v) and a 3-hydroxybutyric acid solution with a concentration of 10 mM; mix the chitosan polymethacrylamide solution and the 3-hydroxybutyric acid solution at a volume ratio of 1:1, add 80 μL of the mixed liquid into a silica micro-needle mold, centrifuge at 2000 rpm for 2 min to allow the solution to fully penetrate into the mold, then evacuate the micro-needle mold, keep the mold at a negative pressure of -0.5 MPa during evacuation, and irradiate at an excitation light wavelength of 365 nm for 30 s for curing to obtain micro-needle tips with a blunt end diameter of 300 μm and a tip length of 800 μm;

[0043] Coat polyvinyl alcohol on the bottom of the silica micro-needle mold for forming micro-needle tips, dry in an oven at 34 °C for 5 h to form a micro-needle base with a thickness of 0.1 mm, pre-freeze at -120 °C for 15 min after demolding, and then freeze-dry at -60 °C for 8 h to obtain an antibacterial and anti-pyroptosis double-layer micro-needle dressing.

[0044] Example 3

[0045] A preparation method of an antibacterial and anti-pyroptosis double-layer micro-needle dressing, comprising the following steps:

[0046] Dissolve chitosan polymethacrylamide (molecular weight 90KDa) and 3-hydroxybutyric acid in water respectively to obtain a chitosan polymethacrylamide solution with a concentration of 10% (w / v) and a 3-hydroxybutyric acid solution with a concentration of 40 mM; mix the chitosan polymethacrylamide solution and the 3-hydroxybutyric acid solution at a volume ratio of 1:1, add 500 μL of the mixed liquid into a silica micro-needle mold, centrifuge at 5000 rpm for 8 min to allow the solution to fully penetrate into the mold, then evacuate the micro-needle mold, keep the mold at a negative pressure of -0.9 MPa during evacuation, and irradiate at an excitation light wavelength of 405 nm for 5 min for curing to obtain micro-needle tips with a blunt end diameter of 600 μm and a tip length of 1500 μm;

[0047] Coat polyvinyl alcohol on the bottom of the silica micro-needle mold for forming micro-needle tips, dry in an oven at 40 °C for 7 h to form a micro-needle base with a thickness of 5 mm, pre-freeze at -60 °C for 45 min after demolding, and then freeze-dry at -40 °C for 16 h to obtain an antibacterial and anti-pyroptosis double-layer micro-needle dressing.

[0048] Experimental Example 1

[0049] Cytotoxicity experiment based on mouse primary bone marrow mesenchymal stem cells (ATCC, USA)

[0050] In a sterile environment, the antibacterial and anti-pyroptosis bilayer microneedle dressing prepared in Example 1 (abbreviated as 3HB-chitosan microneedles in the figure) was cut into a suitable circle according to the pore size of the 96-well plate and placed in the 96-well plate. When placing the antibacterial and anti-pyroptosis bilayer microneedle dressing, the tip of the microneedle was facing upward to contact the cells, and then primary mouse bone marrow mesenchymal stem cells (ATCC, USA) were inoculated, 5000 cells / well, and incubated in a DMEM medium (Gibco, USA) containing 10% fetal bovine serum and 1% penicillin / streptomycin at 37°C and 5% CO2 incubator for 1, 4, and 7 days. And the polyacrylamide chitosan microneedle dressing without 3HB (simplified as chitosan microneedles in the figure, and the preparation method is the same as that in Example 1) was used as the control group, and the group without any microneedle material was used as the blank control group for the experiment. Each treatment was repeated three times.

[0051] On the 1st, 4th, and 7th days of culture, the scaffolds of the three treatment groups were gently rinsed 3 times with PBS, and then 10 μL of CCK-8 solution (Dojindo, Japan) was added to 100 μL of DMEM medium, and incubated for 2 hours at 37°C in the dark. The co-culture solution (the mixture of the dressing and the CCK-8 solution) was transferred to a new 96-well plate, 100 μL per well. Then, the absorbance value of the mixed solution was read at a wavelength of 450 nm using a microplate reader (Multiskan FC, Thermofisher, USA), and the results were as Figure 3 shown. As Figure 3 can be seen, after 7 days of cell culture, neither the antibacterial and anti-pyroptosis bilayer microneedle dressing nor the polyacrylamide chitosan microneedle dressing showed an absorbance value lower than that of the blank control group, and no cytotoxicity was detected in the materials, indicating good cell compatibility.

[0052] Experimental Example 2

[0053] A study was conducted on the ability of the antibacterial and anti-pyroptosis bilayer microneedle dressing prepared in Example 1 to puncture the skin structure.

[0054] The antibacterial and anti-pyroptosis bilayer microneedle dressing prepared in Example 1 was vertically inserted into the intact skin of the mouse back with a force of 50 N, and the results were as Figure 4 (a) shown;

[0055] After 24 hours, the skin tissue at the part punctured by the microneedles was collected, immersed in 4% paraformaldehyde for 24 h, then dehydrated and embedded, and the skin tissue was made into a 10-μm-thick section using a paraffin slicer, and observed under an optical microscope after hematoxylin-eosin staining, and the results were as Figure 4 (b) shown. Figure 4(b) It was confirmed that the antibacterial and anti-pyroptosis bilayer microneedle dressing has the ability to penetrate the intact stratum corneum of the skin at the intact skin site. The experimental results show that the antibacterial and anti-pyroptosis bilayer microneedle dressing prepared in Example 1 has the ability to penetrate the intact skin structure and can penetrate deep into the skin layer during trauma to directly deliver drugs to the deep skin layer and subcutaneous tissue.

[0056] Experimental Example 3

[0057] The antibacterial verification of the antibacterial and anti-pyroptosis bilayer microneedle dressing prepared in Example 1 against Staphylococcus aureus was carried out.

[0058] Taking Staphylococcus aureus (ATCC25923) as the experimental object, the antibacterial activities of the antibacterial and anti-pyroptosis bilayer microneedle dressing obtained in Example 1 and the chitosan microneedles prepared in Experimental Example 1 were evaluated. The experimental steps are as follows:

[0059] 1) Material pretreatment: Place the chitosan microneedle material and 3HB-chitosan microneedle material in a sterile petri dish and perform ultraviolet sterilization (ultraviolet disinfection in a biosafety cabinet, wavelength 260 nm) for 2 h, transfer to a sterile centrifuge tube, and preheat and melt at 42 °C.

[0060] 2) Streak Staphylococcus aureus (ATCC25923) on an LB plate and culture overnight at 37 °C until obvious bacterial colonies are visible.

[0061] 3) Pick a single colony from step 2), streak it on an LB plate, and culture overnight at 37 °C until obvious bacterial colonies are visible.

[0062] 4) Pick an appropriate amount of mature colonies from step 3) and culture them in an LB liquid medium at 37 °C until the OD 600 is 0.6. Adjust the OD of the LBS liquid medium 600 to 0.6, and inoculate the colonies into the LB liquid medium at a ratio of 0.01%, and divide them into the following groups:

[0063] A. Blank control group: Add 1 ml of bacterial liquid to 100 μL of PBS;

[0064] B. Chitosan microneedle group: Add 1 mL of bacterial liquid to 100 μL of chitosan microneedle material (the mixed solution before preparing the microneedles);

[0065] C. 3HB-chitosan microneedle (mixed solution before preparing the microneedles) group: Add 1 mL of bacterial liquid to 100 μL of 3HB-chitosan microneedle material;

[0066] 5) Take groups A, B, and C and add them to the special honeycomb plate of the BIOSCREEN C PRO instrument, 400 μl per well, with 3 replicates for each group

[0067] 6) Place the honeycomb board in the incubator tray of the BIOSCREEN C PRO instrument (a fully automatic growth curve analyzer, brand: BIOSCREEN, model: BIOSCREEN C PRO) for cultivation. Set the oscillation to medium frequency and stop the oscillation 3 minutes before each OD measurement. Set the cultivation temperature to 37 °C and collect the OD value once an hour. 600 As Figure 5 shown, polyacrylamide chitosan as the matrix material of the antibacterial and anti-pyroptosis bilayer microneedle dressing and the blank microneedle has obvious antibacterial properties.

[0068] Experimental Example 4

[0069] Therapeutic effect on the in-vivo skin infection wound of C57BL / 6 mice (purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd.).

[0070] Select 9 healthy female C57BL / 6 mice (8 weeks old) for in-vivo experiments.

[0071] Randomly divide the 9 mice into 3 groups on average. After anesthesia, depilate and prepare the back skin, prepare a circular full-thickness skin defect with a diameter of 10 mm, and inject Staphylococcus aureus bacterial solution (200 μL, 10 9 / mL) at the wound site, as Figure 6 shown. Use 3HB-polyacrylamide chitosan microneedle dressing (simplified as 3HB chitosan microneedle dressing in the figure), polyacrylamide chitosan microneedle dressing (simplified as chitosan microneedle dressing in the figure), and commercially available gauze dressing (Haisi Hainuo, China) to treat the skin wound sites respectively. Observe on the 3rd / 5th / 7th / 9th day after treatment respectively.

[0072] The wound healing conditions on the 3rd / 5th / 7th / 9th day after treatment are as Figure 7 shown, and the quantitative statistics of the wound healing rate are as Figure 8 shown. It can be seen from Figure 7 and Figure 8 that the infected wound healing condition is the best after treatment with 3HB-polyacrylamide chitosan microneedle dressing, that is, the antibacterial and anti-pyroptosis bilayer microneedle dressing described in Example 1 of the present invention; the healing speed is significantly faster than that of other control groups. There is a synergistic effect between 3HB and polyacrylamide chitosan, which can significantly accelerate the healing of infected wounds. Its mechanism of action is that in a body with normal immune function, after the bacteria are successfully inhibited in the initial stage of wound infection (the effective antibacterial component in Example 1 is polyacrylamide chitosan), there is still chronic inflammation in the local skin tissue (mainly caused by bacteria-mediated pyroptosis), which is the main reason for the non-healing of the wound. Therefore, adding the pyroptosis inhibitory component 3HB can effectively reduce the inflammation in the tissue. On the premise that the local tissue bacterial infection of the wound is controlled, the wound healing can be accelerated.

[0073] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of an antibacterial and anti - pyroptosis double - layer microneedle dressing, characterized in that, It includes the following steps: (1) Mix the polymethacrylamide chitosan solution with the 3-hydroxybutyric acid solution, add it into a silica micro-needle mold, and cure to form the micro-needle tip; (2) Coat polyvinyl alcohol on the bottom of the silica micro-needle mold where the micro-needle tip is formed, cure to form the micro-needle base, demold, and dry to obtain the antibacterial and anti-pyroptosis double-layer micro-needle dressing; In step (1), the molecular weight of the polymethacrylamide chitosan is 50-90 KDa; the concentration of the polymethacrylamide chitosan solution is 2-10% (w / v); the concentration of the 3-hydroxybutyric acid solution is 10-40 mM, and the volume ratio of the polymethacrylamide chitosan solution to the 3-hydroxybutyric acid solution is 0.95-1.05:0.95-1.

05.

2. The preparation method according to claim 1, characterized in that, In step (1), the 3-hydroxybutyric acid is replaced by 3-hydroxybutyrate.

3. The preparation method according to claim 1, characterized in that, The curing in step (1) is photocuring, the excitation light wavelength of the photocuring is 365 nm - 405 nm, and the illumination time of the photocuring is 30 s - 5 min.

4. The preparation method according to claim 1, characterized in that, The blunt end diameter of the micro-needle tip is 300 - 600 μm; the length of the micro-needle tip is 800 - 1500 μm.

5. The preparation method according to claim 1, characterized in that, The curing in step (2) is dry curing, the temperature of the dry curing is 34 - 40 °C; the time of the dry curing is 5 - 7 h.

6. The preparation method according to claim 1, characterized in that, The thickness of the micro-needle base in step (2) is 0.1 - 5 mm.

7. The preparation method according to claim 1, characterized in that, The drying in step (2) is freeze-drying, and pre-freezing is carried out before freeze-drying; the temperature of the pre-freezing is -120 °C - -60 °C; the time of the pre-freezing is 15 - 45 min; the temperature of the freeze-drying is -60 °C - -40 °C; the time of the freeze-drying is 8 - 16 h.

8. The antibacterial and anti-pyroptosis double-layer micro-needle dressing prepared by the preparation method according to any one of claims 1 - 7.

9. The application of the antibacterial and anti-pyroptosis double-layer micro-needle dressing according to claim 8 in the preparation of a skin and soft tissue infection wound repair material or a drug.

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