Antibacterial drug delivery system based on dynamic response type microneedle patch and preparation method

Abstract

The invention discloses an antibacterial drug delivery system based on a dynamic response type microneedle patch and a preparation method, and belongs to the field of biomedical materials.The antibacterial drug delivery system comprises a substrate layer and a needle point layer arranged on the surface of the substrate layer, the substrate layer is a mixed matrix of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), and the needle point layer is made of nano-silver; the needle tip layer is a phenylboronic acid modified oxidized hyaluronic acid and polyvinyl alcohol composite system. The antibacterial drug delivery system based on the dynamic response type microneedle patch, namely the microneedle patch with the pH response drug release function, is suitable for antibacterial treatment of infectious wounds, the mechanical strength of the needle point layer is improved, it can be better guaranteed that a microneedle completely penetrates into the skin, and the delivery efficiency is improved; meanwhile, drug release can be responded according to the pH of a bacterial infection part, and the antibacterial effect is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and specifically relates to an antibacterial drug delivery system based on a dynamic response microneedle patch and a preparation method thereof. Background Art

[0002] Microneedle patch is a new transdermal drug delivery technology that penetrates the stratum corneum of the skin through a micron-sized needle structure and delivers drugs directly to the epidermis or dermis. It combines the high efficiency of injection and the convenience of traditional patches.

[0003] Microneedle patches have been used for vaccination, drug delivery (including anticancer drugs, insulin, and dermatology medications), and cosmetic and skin treatments. In the field of antimicrobial drug delivery, microneedle patches loaded with antimicrobial drugs deliver the drugs directly to the infected area, avoiding systemic exposure. The drugs are released after the microneedles dissolve or degrade, creating a localized high-concentration antimicrobial environment and inhibiting bacterial growth. Therefore, microneedle patches loaded with antimicrobial drugs have great application potential. However, existing microneedle patches for antimicrobial drug delivery systems have the following drawbacks: Conventional microneedles lack mechanical strength and have difficulty penetrating the stratum corneum. For example, hyaluronic acid-based microneedle patches have weak mechanical properties. Conventional drug delivery systems lack intelligent release capabilities, which can easily lead to sudden drug release. Targeted drug release cannot be achieved in complex wound environments (such as pH changes caused by bacterial infection). The substrate material dissolves slowly, compromising clinical ease of use. Chinese patent CN202311674053.7 discloses a glucose-responsive antibacterial nanocomposite microneedle patch, its preparation method and application. Under the high-level glucose conditions in the diabetic wound microenvironment, the microneedles efficiently release drugs and do not respond to infections in ordinary people.

[0004] Therefore, due to the above-mentioned usage problems, the application market needs a microneedle patch of antibacterial drugs with comprehensive properties such as excellent mechanical strength and pH responsiveness to achieve better therapeutic effects. Summary of the Invention

[0005] The purpose of the present invention is to provide an antibacterial drug delivery system based on a dynamic responsive microneedle patch and a preparation method. The mechanical strength of the microneedles is sufficient to penetrate the stratum corneum and can achieve targeted drug release according to the pH changes of the wound environment.

[0006] To achieve the above object, the technical solution adopted by the present invention is: The antibacterial drug delivery system based on a dynamic responsive microneedle patch includes a substrate layer and a needle tip layer arranged on the surface of the substrate layer. The substrate layer is a mixed matrix of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), and the needle tip layer is a composite system of phenylboronic acid-modified oxidized hyaluronic acid and polyvinyl alcohol.

[0007] As a limitation of the present invention, the ratio of phenylboronic acid-modified oxidized hyaluronic acid to polyvinyl alcohol in the needle tip layer is 1.5-4:1.

[0008] As a further limitation of the present invention, the drug-loaded microneedles of the antibacterial drug delivery system based on the dynamic response microneedle patch have a needle tip layer comprising a composite system of phenylboronic acid-modified oxidized hyaluronic acid and polyvinyl alcohol and a drug loaded therein.

[0009] As a further limitation of the present invention, the drug loaded in the needle tip layer is a ZIF-8 drug loading system, the concentration of the ZIF-8 drug loading system in the needle tip layer is 0-16 mg / ml, and the drug loaded by the ZIF-8 drug loading system includes a water-soluble antibacterial drug.

[0010] Another object of the present invention is to disclose a method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch, comprising the following steps: Step S1, synthesis of phenylboronic acid-modified oxidized hyaluronic acid: preparing a sodium periodate solution, adding it to a hyaluronic acid (HA) solution, reacting in the dark, adding ethylene glycol to terminate the reaction, dialyzing, and freeze-drying to obtain oxidized hyaluronic acid; dissolving the oxidized hyaluronic acid in water, adding 3-aminophenylboronic acid, terminating the reaction, dialyzing, and freeze-drying to obtain phenylboronic acid-modified oxidized hyaluronic acid (OHA-PBA); Step S2, preparation of the needle tip layer solution: polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution, and OHA-PBA is dissolved in water to prepare an OHA-PBA solution, the two are mixed, and ZIF-8@LVX nanoparticles are added to the mixed solution and mixed evenly; Step S3, preparing a substrate layer solution: dissolving polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) in water to prepare a PVA / PVP hydrogel precursor solution; Step S4, preparation of the microneedle patch: inject the needle tip layer solution into the microneedle mold, vacuum, and scrape off the excess solution to obtain the needle tip of the microneedle; add the substrate layer solution dropwise to the non-needle tip part of the microneedle mold, and dry to obtain the final product.

[0011] As a further limitation of the present invention: the method for preparing the needle tip layer solution of the drug-loaded microneedle is: dissolving polyvinyl alcohol (PVA) in water to prepare a PVA solution, dissolving OHA-PBA in water to prepare an OHA-PBA solution, mixing the two evenly, and adding the ZIF-8 drug-loaded system to the mixed solution and mixing evenly.

[0012] As a further limitation of the present invention: the ZIF-8 drug delivery system is ZIF-8@LVX nanoparticles, which are prepared by: dissolving 2-methylimidazole in methanol and stirring to form a homogeneous solution A; dissolving zinc nitrate hexahydrate in methanol and then mixing uniformly with levofloxacin nanoparticles LVX to obtain solution B; slowly adding solution A to solution B; stirring the mixed solution, standing, centrifuging, washing, and drying.

[0013] As a further limitation of the present invention: in step S1, the mass ratio of hyaluronic acid to sodium periodate is 3:1, the mass volume ratio of hyaluronic acid to ethylene glycol g / mL is 3:4, and the mass ratio of oxidized hyaluronic acid to 3-aminophenylboronic acid is 10:3.

[0014] As a further limitation of the present invention, in step S2, the mass fraction of the polyvinyl alcohol solution is 3%, and the mass fraction of the OHA-PBA solution is 1%.

[0015] As a further limitation of the present invention, in step S3, the PVA concentration in the PVA / PVP hydrogel precursor solution is 5-10%, and the PVP concentration is 15-20%; and in step S4, the microneedle mold is a conical polydimethylsiloxane mold.

[0016] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: The present invention uses phenylboronic acid to react with oxidized hyaluronic acid to modify it to form an OHA-PBA conjugate. OHA-PBA is then cross-linked with PVA to form a composite system of OHA-PBA and PVA. A reversible Schiff base bond is formed between the aldehyde group of OHA and the amino group of PVA. At the same time, the drug is encapsulated in the needle tip layer, which allows for targeted drug release according to pH changes after bacterial infection.

[0017] At the same time, the composite system of phenylboronic acid-modified oxidized hyaluronic acid (OHA-PBA) and polyvinyl alcohol (PVA) in this application also enhances the mechanical strength of the needle tip layer.

[0018] The substrate layer of the present application adopts a polyvinyl alcohol PVA / polyvinyl pyrrolidone (PVP) mixed matrix, which is completely dissolved in normal saline within 3-5 minutes. The substrate material dissolves quickly and is convenient for clinical use. The user does not need to press for a long time, and is suitable for children or patients with low cooperation.

[0019] In summary, the preparation method of the antibacterial drug delivery system based on the dynamic responsive microneedle patch of the present invention is simple and easy to implement. The improvement of the mechanical strength of the needle tip layer can better ensure that the microneedle can completely penetrate the skin and improve the delivery efficiency. The drug is released according to the pH response of the bacterial infection site, and the antibacterial effect is due to the Zn in ZIF-8. 2+ , the loaded drug and oxidized hyaluronic acid are achieved synergistically. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0021] Figure 1 This is a schematic diagram of the microneedle patch structure of this application; Figure 2 This is a SEM image of ZIF-8@LVX of the present application; Figure 3 This is a graph showing the antibacterial rate of an antibacterial drug delivery system based on a dynamic responsive microneedle patch in an experimental example of this application; Figure 4 This is an optical graph of the antibacterial rate of the antibacterial drug delivery system based on the dynamic response microneedle patch of the experimental example of this application; Figure 5 This is a morphological diagram of antibacterial bacteria in the antibacterial drug delivery system based on the dynamic responsive microneedle patch of the experimental example of this application; Figure 6 These are the experimental data of the responses of ZIF-8 and ZIF-8@LVX at different pH values ​​in the experimental examples of this application. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and understand the present invention and are not intended to limit the present invention.

[0023] Example 1 like Figure 1 As shown, an antibacterial drug delivery system based on a dynamic responsive microneedle patch includes a substrate layer and a needle tip layer arranged on the surface of the substrate layer. The substrate layer is a polyvinyl alcohol (PVA) / polyvinyl pyrrolidone (PVP) mixed matrix, and the needle tip layer is a composite system of phenylboronic acid-modified oxidized hyaluronic acid and polyvinyl alcohol and the drug encapsulated therein.

[0024] Example 2 A method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch comprises the following steps: Step 1. Synthesis of Phenylboronic Acid-Modified Oxidized Hyaluronic Acid: Weigh 1.50g of hyaluronic acid and dissolve thoroughly in 150ml of reverse osmosis water. Dissolve 0.5g of sodium periodate in 10ml of reverse osmosis water and add to the completely dissolved hyaluronic acid. Stir in the dark for 4 hours. Add 2ml of ethylene glycol and allow to react for 1 hour to terminate the reaction. Dialyze for 3 days, changing the water 6-8 times, and freeze-dry for storage.

[0025] Weigh 1.0g of oxidized hyaluronic acid and dissolve thoroughly in 50ml of RO water. Then add 0.3g of 3-aminophenylboronic acid and allow to react for 12 hours. Dialyze the solution against RO water for 3 days, changing the water 6-8 times. Freeze-dry and set aside.

[0026] Step 2. Preparation of hydrogel-responsive needle tips: Weigh 1.5 g of polyvinyl alcohol using an analytical balance and dissolve it in 48.5 ml of RO water at 95°C. Weigh 0.5 g of phenylboronic acid-modified oxidized hyaluronic acid and dissolve it in 49.5 ml of RO water until completely dissolved. Mix the two in a 1:1 volume ratio to form a pH / ROS-responsive hydrogel.

[0027] Step 3, preparation of substrate layer solution: polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) are dissolved in water to prepare a PVA / PVP hydrogel precursor solution, wherein the concentration of PVA is 10% and the concentration of PVP is 15%; Step 4. Preparation of microneedle patch: The pH / ROS-responsive hydrogel prepared in step 2 was injected into a microneedle mold on a conical polydimethylsiloxane (PDMS) mold (the diameter of the cone bottom is 300 μm and the height is 600 μm). Then, the mold was vacuumed for 5 minutes and the excess solution was scraped off to obtain the tip of the microneedle. The substrate layer solution was added dropwise to the non-tip part of the microneedle mold and dried to obtain the final product.

[0028] Example 3 A method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch comprises the following steps: Step 1. Synthesis of Phenylboronic Acid-Modified Oxidized Hyaluronic Acid: Weigh 1.50g of hyaluronic acid and dissolve thoroughly in 150ml of reverse osmosis water. Dissolve 0.5g of sodium periodate in 10ml of reverse osmosis water and add to the completely dissolved hyaluronic acid. Stir in the dark for 4 hours. Add 2ml of ethylene glycol and allow to react for 1 hour to terminate the reaction. Dialyze for 3 days, changing the water 6-8 times, and freeze-dry for storage.

[0029] Weigh 1.0g of oxidized hyaluronic acid and dissolve thoroughly in 50ml of RO water. Then add 0.3g of 3-aminophenylboronic acid and allow to react for 12 hours. Dialyze the solution against RO water for 3 days, changing the water 6-8 times. Freeze-dry and set aside.

[0030] Step 2. Preparation of hydrogel-responsive needle tips: Weigh 1.5 g of polyvinyl alcohol using an analytical balance and dissolve it in 48.5 ml of RO water at 95°C. Weigh 0.5 g of phenylboronic acid-modified oxidized hyaluronic acid and dissolve it completely in 49.5 ml of RO water. Mix the two in a 1:1 volume ratio to form a pH / ROS-responsive hydrogel.

[0031] Step 3. Preparation of ZIF-8 Nanoparticles: Dissolve 325 mg of 2-methylimidazole in 10 ml of methanol and stir at room temperature for 30 minutes to form a homogeneous solution A. Add 147 mg of zinc nitrate hexahydrate to 5 ml of methanol to form a homogeneous solution B. Slowly add solution A to solution B. The mixed solution is vigorously stirred at 37°C for 30 minutes and then allowed to stand for 9 hours. Centrifuge, wash three times with methanol, and vacuum dry or oven dry to obtain ZIF-8 nanoparticles. Step 4, preparation of the needle tip layer solution: adding ZIF-8 nanoparticles to the pH / ROS responsive hydrogel and mixing them evenly, wherein the concentration of ZIF-8 is 16 mg / ml; Step 5, preparation of substrate layer solution: polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) are dissolved in water to prepare a PVA / PVP hydrogel precursor solution, wherein the concentration of PVA is 10% and the concentration of PVP is 15%; Step 6. Preparation of microneedle patch: Inject the tip layer solution in step 4 into the microneedle mold and onto a conical polydimethylsiloxane (PDMS) mold (the diameter of the cone bottom is 300 μm and the height is 600 μm). Then, vacuum for 5 minutes and scrape off the excess solution to obtain the tip of the microneedle. Add the substrate layer solution dropwise to the non-tip part of the microneedle mold and dry it to obtain the final product.

[0032] Example 4 A method for preparing a drug-loaded microneedle patch comprises the following steps: Step 1. Synthesis of Phenylboronic Acid-Modified Oxidized Hyaluronic Acid: Weigh 1.50g of hyaluronic acid and dissolve thoroughly in 150ml of reverse osmosis water. Dissolve 0.5g of sodium periodate in 10ml of reverse osmosis water and add to the completely dissolved hyaluronic acid. Stir in the dark for 4 hours. Add 2ml of ethylene glycol and allow to react for 1 hour to terminate the reaction. Dialyze for 3 days, changing the water 6-8 times, and freeze-dry for storage.

[0033] Weigh 1.0g of oxidized hyaluronic acid and dissolve thoroughly in 50ml of RO water. Then add 0.3g of 3-aminophenylboronic acid and allow to react for 12 hours. Dialyze the solution with RO water for 3 days, changing the water 6-8 times. Freeze-dry and set aside.

[0034] Step 2. Preparation of hydrogel-responsive needle tips: Weigh 1.5 g of polyvinyl alcohol using an analytical balance and dissolve it in 48.5 ml of RO water at 95°C. Weigh 0.5 g of phenylboronic acid-modified oxidized hyaluronic acid and dissolve it in 49.5 ml of RO water until completely dissolved. Mix the two in a 1:1 volume ratio to form a pH / ROS-responsive hydrogel.

[0035] Step 3. Preparation of ZIF-8@LVX Nanoparticles: Dissolve 325 mg of 2-methylimidazole in 10 ml of methanol and stir at room temperature for 30 minutes to form a homogeneous solution A. Add 147 mg of zinc nitrate hexahydrate to 5 ml of methanol and ultrasonically vibrate with 14 mg of LVX to form a homogeneous solution B. Slowly add solution A to solution B. The mixed solution is vigorously stirred at 37°C for 30 minutes and then allowed to stand for 9 hours. Centrifuge, wash three times with methanol, and dry in a vacuum or oven.

[0036] like Figure 2 The figure shows the SEM image of ZIF-8@LVX. The prepared ZIF-8@LVX has a regular hexagonal dodecahedron morphology.

[0037] Step 4: Preparation of the needle tip layer solution: Add ZIF-8@LVX nanoparticles to the pH / ROS-responsive hydrogel and mix well. The concentration of ZIF-8@LVX is 2 mg / ml. Step 5, preparation of substrate layer solution: polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) are dissolved in water to prepare a PVA / PVP hydrogel precursor solution, wherein the concentration of PVA is 10% and the concentration of PVP is 15%; Step 6: Preparation of drug-loaded microneedle patch: The tip layer solution prepared in step 4 was injected into the microneedle mold and placed on a conical polydimethylsiloxane (PDMS) mold (the diameter of the cone bottom was 300 μm and the height was 600 μm). The mold was then vacuumed for 5 minutes and the excess solution was scraped off to obtain the tip of the microneedle. The substrate layer solution was added dropwise to the non-tip part of the microneedle mold and dried to obtain the final product.

[0038] Example 5 A method for preparing a drug-loaded microneedle patch comprises the following steps: Step 1. Synthesis of Phenylboronic Acid-Modified Oxidized Hyaluronic Acid: Weigh 1.50g of hyaluronic acid and dissolve thoroughly in 150ml of reverse osmosis water. Dissolve 0.5g of sodium periodate in 10ml of reverse osmosis water and add to the completely dissolved hyaluronic acid. Stir in the dark for 4 hours. Add 2ml of ethylene glycol and allow to react for 1 hour to terminate the reaction. Dialyze for 3 days, changing the water 6-8 times, and freeze-dry for storage.

[0039] Weigh 1.0g of oxidized hyaluronic acid and dissolve thoroughly in 50ml of RO water. Then add 0.3g of 3-aminophenylboronic acid and allow to react for 12 hours. Dialyze the solution with RO water for 3 days, changing the water 6-8 times. Freeze-dry and set aside.

[0040] Step 2. Preparation of hydrogel-responsive needle tips: Weigh 1.5 g of polyvinyl alcohol using an analytical balance and dissolve it in 48.5 ml of RO water at 95°C. Weigh 0.5 g of phenylboronic acid-modified oxidized hyaluronic acid and dissolve it in 49.5 ml of RO water until completely dissolved. Mix the two in a volume ratio of 1:2 to form a pH / ROS-responsive hydrogel.

[0041] Step 3. Preparation of ZIF-8@LVX Nanoparticles: Dissolve 325 mg of 2-methylimidazole in 10 ml of methanol and stir at room temperature for 30 minutes to form a homogeneous solution A. Add 147 mg of zinc nitrate hexahydrate to 5 ml of methanol and ultrasonically vibrate with 14 mg of LVX to form a homogeneous solution B. Slowly add solution A to solution B. The mixed solution is vigorously stirred at 37°C for 30 minutes and then allowed to stand for 9 hours. Centrifuge, wash three times with methanol, and dry in a vacuum or oven.

[0042] Step 4, preparation of the needle tip layer solution: ZIF-8@LVX nanoparticles were added to the pH / ROS responsive hydrogel and mixed evenly, wherein the concentration of ZIF-8@LVX was 4 mg / ml; Step 5, preparation of substrate layer solution: polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) are dissolved in water to prepare a PVA / PVP hydrogel precursor solution, wherein the concentration of PVA is 10% and the concentration of PVP is 15%; Step 6: Preparation of drug-loaded microneedle patch: The tip layer solution prepared in step 4 was injected into the microneedle mold and placed on a conical polydimethylsiloxane (PDMS) mold (the diameter of the cone bottom was 300 μm and the height was 600 μm). The mold was then vacuumed for 5 minutes and the excess solution was scraped off to obtain the tip of the microneedle. The substrate layer solution was added dropwise to the non-tip part of the microneedle mold and dried to obtain the final product.

[0043] Example 6 This embodiment is substantially the same as embodiment 4, except that the concentration of ZIF-8@LVX in the tip layer solution in step 4 is 8 mg / ml.

[0044] Example 7 This embodiment is substantially the same as embodiment 4, except that the concentration of ZIF-8@LVX in the tip layer solution in step 4 is 12 mg / ml.

[0045] Example 8 This embodiment is substantially the same as embodiment 4, except that the concentration of ZIF-8@LVX in the tip layer solution in step 4 is 16 mg / ml.

[0046] Experimental Example 1 Antibacterial performance test The experiments were carried out using the microneedle patches prepared in Examples 2-8.

[0047] The antibacterial activity of drug-loaded microneedles was tested by co-culturing them with Staphylococcus aureus and Pseudomonas aeruginosa. The drug-loaded microneedles were first sterilized by ultraviolet irradiation for 1 hour. Then, 1 ml of 10% dapoxetine was added to each well of a 48-well plate. 6 CFu / ml bacterial suspension, then the microneedle patch loaded with different concentrations of LVFX@ZIF-8 was immersed in the bacterial suspension of the 48-well plate (5 parallel samples per group), and then the well plate was placed in a 37℃ incubator for 24 hours, and then the bacterial suspension was diluted 10,000 times with liquid culture medium, and then 100 μL of bacterial suspension was evenly spread on the solid culture medium, and incubated at 37℃ for 12 hours, and then taken out for observation and photography, as shown in the figure. Figure 4 The blank control group was the microneedle patch prepared in Example 2 without the addition of the ZIF-8 system; 0 mg / ml represents the experimental results of the microneedle patch prepared in Example 3. 4 mg / ml, 8 mg / ml, 12 mg / ml, and 16 mg / ml represent the microneedle patches prepared in Examples 5, 6, 7, and 8, respectively.

[0048] Antibacterial rate experiment The antibacterial activity of drug-loaded microneedles was tested by co-culturing them with Staphylococcus aureus and Pseudomonas aeruginosa. The microneedles were sterilized by ultraviolet irradiation for 1 hour. Then, 1 ml of 10% dapoxetine was added to each well of a 48-well plate. 6 CFu / ml bacterial suspension, then the microneedle patch loaded with different concentrations of LVFX@ZIF-8 was immersed in the bacterial suspension of 48-well plate (5 parallel samples per group), and then the well plate was placed in a 37℃ incubator for 24h, and then the bacterial solution after co-culture in the 48-well plate was aspirated into a 96-well plate, the enzyme-labeled OD value was measured, and the antibacterial rate was calculated according to the formula. The statistical results are shown as follows Figure 3 The blank control group represents the microneedle patch prepared in Example 2 without the addition of the ZIF-8 system; 0 mg / ml represents the experimental results of the microneedle patch prepared in Example 3. 2 mg / ml, 4 mg / ml, 8 mg / ml, 12 mg / ml, and 16 mg / ml represent the drug-loaded microneedle patches prepared in Examples 4, 5, 6, 7, and 8, respectively.

[0049] The results show that microneedle patches with different nanozyme concentrations have inhibitory effects on Pseudomonas aeruginosa and Staphylococcus aureus. When the nanozyme concentration reaches 16 mg / mL, the antibacterial rate against Pseudomonas aeruginosa and Staphylococcus aureus reaches more than 95%.

[0050] In order to understand the situation of bacterial death, the microscopic morphology of two bacteria treated with microneedle patches of different nanozyme concentrations was observed by SEM. Figure 5As shown, the normal bacteria in the untreated and low-nanozyme concentration groups were numerous and intact, with plump bodies, smooth surfaces without depressions, and densely packed. However, after treatment with microneedle patches containing varying nanozyme concentrations, the number of both bacteria decreased significantly, with no significant bacterial presence under SEM observation. Furthermore, both bacteria showed signs of shrinkage and rupture, and surrounding them were intracellular substances produced by the lysis of bacterial cell walls and membranes.

[0051] Experimental Example 2 Different pH response experiments: Experiments were conducted on the response of ZIF-8 and ZIF-8@LVX particles at different pH.

[0052] The concentration of ZIF-8 and ZIF-8@LVX used was 2 mg / ml. The structural disintegration process of ZIF-8 and ZIF-8@LVX was investigated at pH 5.5 for 1 hour and 2 hours, pH 6.0 for 2 hours, and pH 7.4 for 2 hours. The grouped well plates were placed in a 37°C incubator for the reaction response time. After the reaction, 2.5% glutaraldehyde was added to fix the structure. The plates were washed three times with ultrapure water and then placed in a drying cabinet for 24 hours. Observation and photography were performed. Figure 6 .

[0053] The structural disintegration process of ZIF-8 and ZIF-8@LVX in an acidic environment (pH 5.0-6.5) was observed, and the morphological changes were established. The crystal morphology changes at different pH values ​​were observed under SEM. The samples were grouped and processed as follows: Processing conditions Buffer system Processing time Control group (pH 7.4) PBS (0.1M, 7.4) 2 hours Response group (pH 5.5) Simulated body fluids 1 hour, 2 hours Critical group (pH 6.5) Simulated body fluids 2 hours Figure 6 The results show that ZIF-8 and ZIF-8@LVX will cause structural collapse in an acidic environment and are stable in a neutral environment, indicating that both have the ability to respond to acid environment release, that is, they can respond in a bacterial environment.

[0054] The antibacterial mechanism of the antibacterial drug delivery system based on the dynamic responsive microneedle patch of this application is as follows: bacterial metabolism leads to acidification of the microenvironment, with a pH of 5.0-6.5. The Schiff base bond of the microneedle patch of this application breaks, and then the needle tip layer dissolves rapidly. After the needle tip layer dissolves, ZIF-8@LVX is released. Under acidic conditions, the ZIF-8 structure collapses and Zn is released synchronously. 2+ and LVX.

[0055] Therefore, the microneedle patch of the present application has a synergistic antibacterial effect, Zn² +Disrupting bacterial membrane potential, inhibiting DNA gyrase with LVX, and promoting macrophage activation with oxidized hyaluronic acid, all work simultaneously. This application demonstrates the effectiveness of ZIF-8@LVX as an example. ZIF-8 can also be loaded with other water-soluble antibacterial drugs, allowing for the preparation of microneedle patches tailored to specific needs to achieve the desired antibacterial effect.

[0056] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may still modify the technical solutions described in the above embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An antimicrobial drug delivery system based on a dynamic responsive microneedle patch, comprising a substrate layer and a needle tip layer disposed on the surface of the substrate layer, characterized in that: The substrate layer is a mixed matrix of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), and the needle tip layer is a composite system of phenylboronic acid-modified oxidized hyaluronic acid and polyvinyl alcohol.

2. The antimicrobial drug delivery system based on a dynamic response microneedle patch according to claim 1, characterized in that: The mass ratio of phenylboronic acid modified oxidized hyaluronic acid to polyvinyl alcohol in the needle tip layer is 1.5-4:

1.

3. The antimicrobial drug delivery system based on a dynamic response microneedle patch according to claim 1, characterized in that: The drug-loaded microneedles of the antibacterial drug delivery system based on the dynamic response microneedle patch have a needle tip layer comprising a composite system of phenylboronic acid-modified oxidized hyaluronic acid and polyvinyl alcohol and drugs loaded therein.

4. The antimicrobial drug delivery system based on a dynamic responsive microneedle patch according to claim 3, characterized in that: The drug loaded in the needle tip layer is a ZIF-8 drug loading system, the concentration of the ZIF-8 drug loading system in the needle tip layer is 0-16 mg / ml, and the drug loaded in the ZIF-8 drug loading system includes a water-soluble antibacterial drug.

5. A method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch, characterized in that: Step S1, synthesis of phenylboronic acid-modified oxidized hyaluronic acid: preparing a sodium periodate solution, adding it to a hyaluronic acid (HA) solution, reacting in the dark, adding ethylene glycol to terminate the reaction, dialyzing, and freeze-drying to obtain oxidized hyaluronic acid; dissolving the oxidized hyaluronic acid in water, adding 3-aminophenylboronic acid, terminating the reaction, dialyzing, and freeze-drying to obtain phenylboronic acid-modified oxidized hyaluronic acid (OHA-PBA); Step S2, preparation of the needle tip layer solution: dissolving polyvinyl alcohol (PVA) in water to prepare a PVA solution, dissolving OHA-PBA in water to prepare an OHA-PBA solution, and mixing the two uniformly; Step S3, preparing a substrate layer solution: dissolving polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) in water to prepare a PVA / PVP hydrogel precursor solution; Step S4, preparation of the microneedle patch: inject the needle tip layer solution into the microneedle mold, vacuum, and scrape off the excess solution to obtain the needle tip of the microneedle; add the substrate layer solution dropwise to the non-needle tip part of the microneedle mold, and dry to obtain the final product.

6. The method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch according to claim 5, characterized in that: The needle tip layer solution of the drug-loaded microneedle is prepared by dissolving polyvinyl alcohol (PVA) in water to prepare a PVA solution, dissolving OHA-PBA in water to prepare an OHA-PBA solution, mixing the two evenly, and adding the ZIF-8 drug-loaded system to the mixed solution and mixing evenly.

7. The method for preparing the antimicrobial drug delivery system based on the dynamic response microneedle patch according to claim 6, characterized in that: The ZIF-8 drug delivery system is ZIF-8@LVX nanoparticles, which are prepared by dissolving 2-methylimidazole in methanol and stirring to form a homogeneous solution A, dissolving zinc nitrate hexahydrate in methanol and then mixing it evenly with levofloxacin nanoparticles LVX to obtain solution B, slowly adding solution A to solution B, and stirring the mixed solution, standing, centrifuging, washing, and drying.

8. The method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch according to claim 5, characterized in that: In step S1, the mass ratio of hyaluronic acid to sodium periodate is 3:1, the mass volume ratio of hyaluronic acid to ethylene glycol is 3:4 in g / mL, and the mass ratio of oxidized hyaluronic acid to 3-aminophenylboronic acid is 10:

3.

9. The method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch according to claim 5, characterized in that: In step S2, the mass fraction of the polyvinyl alcohol solution is 3%, and the mass fraction of the OHA-PBA solution is 1%.

10. The method for preparing an antimicrobial drug delivery system based on a dynamic responsive microneedle patch according to claim 5, characterized in that: In step S3, the PVA concentration in the PVA / PVP hydrogel precursor solution is 5-10%, and the PVP concentration is 15-20%. In step S4, the microneedle mold is a conical polydimethylsiloxane mold.

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