A zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties and its preparation and application

Abstract

The present invention relates to a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties and its preparation and application, and belongs to the field of antibacterial technology. A zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties, the dispersion is composed of zinc oxide nanoparticles, 1-butyl-3-methylimidazolium chloride ionic liquid and water, the ratio of the ionic liquid to water is 1-128mmol:1L; the ratio of the zinc oxide nanoparticles to water is 1-64mg:100mL. At the same time, the present invention provides a soluble microneedle with the dispersion as an antibacterial active ingredient. The soluble microneedle is an integrated microneedle prepared by ultraviolet crosslinking using synthetic methacrylated hyaluronic acid as a matrix, and has good mechanical properties, puncture ability and antibacterial properties.

Description

Technical Field

[0001] The invention relates to a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties and preparation and application thereof, belonging to the technical field of antibacterial properties. Background Art

[0002] A series of infectious diseases caused by bacteria have always seriously threatened global public health and safety. Although antibiotics are currently the most commonly used drugs for the treatment of bacterial and biofilm infections in clinical practice. However, with the abuse of antibiotics, antibiotic drugs not only cause a lot of waste, but also the related drug resistance problems, adverse reactions and other hazards are becoming more and more serious. Therefore, there is an urgent need for some "ideal antibacterial agents" (not involving antibiotics) that are highly efficient, durable and safe to cope with increasingly complex and stubborn bacterial infectious diseases, so as to overcome the many drawbacks of traditional antibiotic treatment.

[0003] The use of nanomaterials to replace antibiotics has developed rapidly in the past decade. Among them, zinc oxide nanoparticles have been shown to have antibacterial properties and low toxicity in the treatment of microbial infections and have been used in antibacterial preparations. However, one of the problems with zinc oxide nanoparticles is that the particles do not disperse well in general media, which reduces their antibacterial effect. Ionic liquids are a class of low-melting-point salts containing organic cations and organic / inorganic anions with good biocompatibility. They can not only enhance the dispersibility of zinc oxide nanoparticles, but also have antibacterial properties themselves.

[0004] Microneedles are an emerging transdermal drug delivery platform because they can effectively establish transport channels in the epidermis and deliver drugs to a predetermined depth without causing pain, skin damage or excessive irritation. Soluble microneedles are one of many types of microneedles, usually made from a series of water-soluble macromolecules. When piercing the skin, they can absorb interstitial fluid and dissolve in the subcutaneous tissue, thereby releasing active ingredients. Water-soluble microneedles avoid repeated insertion and removal of microneedles, reduce the risk of infection in patients and the generation of medical waste, and have emerged as a green, effective, minimally invasive, painless penetration-enhancing technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an antibacterial agent that can replace antibiotics, and to prepare it into a soluble microneedle, which can deliver the antibacterial agent to the dermis. The integrated soluble microneedle has good antibacterial properties and can effectively inhibit the growth of Escherichia coli and Staphylococcus aureus. On the one hand, a safe, effective and low-cost antibacterial agent has been found, and on the other hand, it can be prepared into a soluble microneedle to provide a possibility of treating wound infection.

[0006] The invention discloses a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties. The dispersion consists of zinc oxide nanoparticles, 1-butyl-3-methylimidazolium chloride ionic liquid and water.

[0007] The dispersion of the invention is composed of zinc oxide nanoparticles dispersed in 1-butyl-3-methylimidazolium chloride ionic liquid / water solvent.

[0008] Furthermore, the ratio of the ionic liquid to water is 1 to 128 mmol: 1 L. The present invention preferably dissolves 1-butyl-3-methylimidazolium chloride ionic liquid in deionized water according to the above ratio to form a 1-butyl-3-methylimidazolium chloride ionic liquid / water solvent.

[0009] Furthermore, the ratio of the zinc oxide nanoparticles to water is 1-64 mg:100 mL. In the present invention, the zinc oxide nanoparticles are preferably dispersed in the formed 1-butyl-3-methylimidazolium chloride ionic liquid / water solvent according to the above ratio to form a dispersion.

[0010] Furthermore, the size of the zinc oxide nanoparticles is 50±10 nm.

[0011] Another object of the present invention is to provide a method for preparing the zinc oxide nanoparticle / ionic liquid dispersion having synergistic antibacterial properties.

[0012] A method for preparing a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties comprises preparing an ionic liquid / water solvent of a certain concentration, and uniformly dispersing the zinc oxide nanoparticles in the ionic liquid / water solvent by ultrasound.

[0013] The above-mentioned "ultrasound" of the present invention can be accomplished by using ultrasonic equipment provided by the prior art, and those skilled in the art can achieve the purpose of uniform dispersion by adjusting parameters.

[0014] The present invention also provides the use of the zinc oxide nanoparticle / ionic liquid dispersion having synergistic antibacterial properties as an antibacterial agent.

[0015] Another object of the present invention is to provide a soluble microneedle using the zinc oxide nanoparticle / ionic liquid dispersion as an antibacterial active ingredient.

[0016] An integrated soluble microneedle is obtained by attaching a precursor solution to a patch substrate for ultraviolet crosslinking, wherein the precursor solution is composed of a matrix, a photoinitiator and a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties, and the ratio of the dispersion to the matrix in the precursor solution is 1 mL: 60-120 mg; the photoinitiator is 1-hydroxycyclohexyl phenyl ketone (HCPK), and the ratio of HCPK to the dispersion is 1 mg: 2 mL.

[0017] The ratio of ionic liquid to water in the dispersion is 10 mmol:1 L; the ratio of zinc oxide nanoparticles to water in the dispersion is 12-48 mg:100 mL; the matrix is ​​methacrylated hyaluronic acid, and the grafting rate is 12%-22%.

[0018] In the above technical solution, the zinc oxide nanoparticles / ionic liquid dispersion with synergistic antibacterial properties is used as an antibacterial active ingredient.

[0019] Preferably, the precursor solution further comprises a medical antibacterial agent or a medical cosmetic ingredient.

[0020] Furthermore, the matrix methacrylated hyaluronic acid is prepared by the following method: methacrylic anhydride and hyaluronic acid are mixed at a temperature below 4°C and the pH is maintained between 8 and 9 for reaction.

[0021] Wherein, the molecular weight of the hyaluronic acid is 100 kDa to 400 kDa; and the molar ratio of methacrylic anhydride to hyaluronic acid is 3 to 10:1.

[0022] The method for preparing the integrated soluble microneedle comprises the following process steps:

[0023] Dissolve methacrylated hyaluronic acid and HCPK in zinc oxide nanoparticle / ionic liquid dispersion, stir evenly, and let stand to remove bubbles to obtain a microneedle precursor solution; inject the microneedle precursor solution into the PDMS mold and centrifuge until the solution fills the needle tip; place the centrifuged microneedles under ultraviolet light for cross-linking; after cross-linking, dry for 24 hours.

[0024] The needle body of the PDMS mold is in the shape of a quadrangular pyramid or a cone, and the needle length is 600-1000 μm; the centrifugal speed is 3000-4000 rpm, and the centrifugal time is 5-20 min; the cross-linking time is 30 s-5 min; and the drying condition is room temperature drying.

[0025] In the above technical solution, the crosslinking agent is methacrylated hyaluronic acid, that is, the methacrylated hyaluronic acid plays the role of matrix and crosslinking agent at the same time.

[0026] The beneficial effects of the present invention are as follows: the present invention relates to a zinc oxide nanoparticle / ionic liquid dispersion and a preparation method thereof, and at the same time, the present invention provides a soluble microneedle with the dispersion as an antibacterial active ingredient. The soluble microneedle is an integrated microneedle prepared by ultraviolet crosslinking using a synthetic methacrylated hyaluronic acid as a matrix, and has good mechanical properties and puncture ability. The microneedle tip can dissolve and release the antibacterial agent in a short time. The dispersibility of zinc oxide nanoparticles in ionic liquid (1-butyl-3-methylimidazolium chloride) is much better than that in deionized water, so that the zinc oxide nanoparticles and the ionic liquid have a synergistic antibacterial effect. Using the zinc oxide nanoparticle / ionic liquid dispersion as an antibacterial agent can reduce the amount of the antibacterial agent in the soluble microneedle. The soluble microneedle has good antibacterial properties both in vivo and in vitro. The antibacterial agent in the microneedle can be released in a short time as the needle tip dissolves, playing an antibacterial or therapeutic role for skin infection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the minimum inhibitory concentration of ionic liquid solution and zinc oxide nanoparticles / deionized water.

[0028] Figure 2 Minimum inhibitory concentration and partial inhibitory concentration index for the combination of ionic liquid solution and zinc oxide nanoparticles / deionized water.

[0029] Figure 3 The dispersion of zinc oxide nanoparticles in ionic liquid.

[0030] Figure 4 The antibacterial effect diagram of zinc oxide nanoparticles / deionized water dispersions with different concentrations.

[0031] Figure 5 This is a flow chart for preparing the microneedle patch of Example 2.

[0032] Figure 6 These are the intuitive pictures, microscope and scanning electron microscope pictures of the microneedle patch prepared in Example 2.

[0033] Figure 7 This is a graph showing the pig skin puncture ability of the microneedle patch prepared in Example 2.

[0034] Figure 8 This is a diagram showing the healing status of the microneedle patch prepared in Example 2 applied to mouse skin.

[0035] Fig. 9 This is the in vivo dissolution diagram of the microneedle patch prepared in Example 2.

[0036] Fig.10 This is a diagram showing the antibacterial effect of bacterial liquid co-culture on the microneedle patch prepared in Example 2.

[0037] Fig.11 This is a growth curve diagram of the microneedle patch prepared in Example 2.

[0038] Fig.12 This is a wound healing picture of the microneedle patch prepared in Example 2. DETAILED DESCRIPTION

[0039] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0040] The test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0041] A zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties. The dispersion is composed of zinc oxide nanoparticles dispersed in 1-butyl-3-methylimidazolium chloride ionic liquid / water solvent, wherein the ratio of the ionic liquid to water is 1-128 mmol:1L; and the ratio of the zinc oxide nanoparticles to water is 1-64 mg:100 mL.

[0042] The above zinc oxide nanoparticle / ionic liquid dispersion is prepared and measured by the following steps: preparing an ionic liquid solvent of a certain concentration; preparing zinc oxide nanoparticle / deionized water dispersions of different concentrations; dispersing the zinc oxide nanoparticle / ionic liquid dispersion by ultrasound; and measuring by a Malvern particle size analyzer.

[0043] In the following embodiments, the ultrasonic equipment KQ-250B ultrasonic cleaning instrument used in the present invention has an ultrasonic water volume of 1000-3000 mL and an ultrasonic time of 5-20 min.

[0044] In the following embodiments, the synergistic antibacterial effect of the zinc oxide nanoparticle / ionic liquid dispersion is demonstrated by the following steps: preparing ionic liquid solutions of different concentrations; preparing zinc oxide nanoparticle dispersions of different concentrations; obtaining the minimum inhibitory concentration and the minimum bactericidal concentration by co-culturing the ionic liquid solution and the zinc oxide nanoparticle dispersion with the bacterial solution respectively; obtaining the minimum inhibitory concentration when the ionic liquid solution and the zinc oxide nanoparticle dispersion are used in combination and co-culturing with the bacterial solution; and judging the synergistic antibacterial effect by calculating the partial inhibitory concentration index.

[0045] The bacterial liquids selected are Escherichia coli and Staphylococcus aureus, and the method used is the chessboard method combined with drug sensitivity test.

[0046] The formula used in the above calculation is FIC = MIC when drug A is used in combination / MIC when drug A is used alone + MIC when drug B is used in combination / MIC when drug B is used alone. The judgment basis is that FIC ≤ 0.5 indicates a synergistic effect; 0.5 < FIC ≤ 1 indicates an additive effect; 1 < FIC ≤ 2 indicates an irrelevant effect; FIC > 2 indicates an antagonistic effect.

[0047] The following examples further provide an integrated soluble microneedle for wound infection.

[0048] The microneedle patch described is a soluble microneedle; the soluble microneedle is prepared by attaching a precursor solution to a patch substrate; the precursor solution includes a matrix and an active ingredient. The ratio of the dispersion to the matrix in the precursor solution is 1 mL: 60 - 120 mg.

[0049] Among them, the ratio of the ionic liquid to water in the dispersion is 10 mmol: 1 L; the ratio of zinc oxide nanoparticles to water in the dispersion is 12 - 48 mg: 100 mL; the matrix is methacrylated hyaluronic acid, and the grafting rate is 12% - 22%.

[0050] The microneedle patch described is prepared by ultraviolet cross - linking. Cross - linking refers to ultraviolet cross - linking using a cross - linker as the cross - linking means, and the cross - linker is methacrylated hyaluronic acid.

[0051] The soluble microneedle patch is prepared by the following steps: Dissolve methacrylated hyaluronic acid in the zinc oxide nanoparticle / ionic liquid dispersion, stir evenly, stand to remove bubbles to obtain a microneedle precursor solution; Inject the microneedle precursor solution into a PDMS mold, and centrifuge until the solution fills the needle tips; Place the centrifuged microneedles under an ultraviolet lamp for cross - linking; After cross - linking, dry for 24 h.

[0052] The needle body shape of the PDMS mold is a quadrangular pyramid, the needle length is 600 - 1000 μm; the centrifugation speed is 3000 - 4000 rpm, the centrifugation time is 5 - 20 min; the cross - linking time is 30 s - 5 min; the drying condition is drying at room temperature.

[0053] The microneedle has a needle length of 600 - 1000 μm, the bottom size of the needle is 280 - 500 μm, the distance between the needle tips is 500 - 1000 μm, the array number is 100 (10 * 10) - 225 (15 * 15), the size of the microneedle patch is 8.9 * 8.9 - 16.6 * 16.6 mm, the depth of the edge groove is 1.5 - 2.5 mm, the mold material is silicone or PDMS, and the style is a conventional patch mold.

[0054] The microneedle patch has good mechanical properties and good puncture rate. The microneedle patch has good recovery performance on rat skin and is non-irritating. At the same time, the microneedle patch has good dissolution performance, good in vitro blood compatibility, and good ability to inhibit bacterial growth.

[0055] In the following examples, the matrix methacrylated hyaluronic acid (MeHA) used was prepared by the following method: methacrylic anhydride and hyaluronic acid were mixed at a molar ratio of 3:1 below 4°C, and the pH was maintained between 8 and 9 for reaction.

[0056] Example 1

[0057] (1) Preparation of zinc oxide nanoparticles / ionic liquids:

[0058] ZnO nanoparticles were suspended in ionic liquid / deionized water and ultrasonicated for 5 min. The ratio of ionic liquid to water was 10 mmol:1 L, and the ratio of zinc oxide nanoparticles to water was 9, 10, 11, 12, and 13 mg:100 mL, respectively. The particle size and polydispersity index were measured on a Marvin particle size analyzer.

[0059] (2) Minimum inhibitory concentration and minimum bactericidal concentration:

[0060] Add 50 μL of 10% 6 CFU / mL of logarithmic phase bacteria, 50μL of liquid culture medium, and then add 100μL of different concentrations of ZnO / DIW dispersion and different concentrations of IL. The final concentrations of ZnO / DIW dispersion are 0.01, 0.02, 0.04, 0.08, 0.16, 0.32, and 0.64mg / ml, and the final concentrations of IL are 1, 2, 4, 8, 16, 32, and 64mmol / L, respectively. A blank control is also set up, and the culture is incubated at 37℃ for 24h. After the culture is completed, the absorbance value of each well of the 96-well plate is measured by an enzyme reader. The sample concentration in the well with an absorbance value less than or equal to the blank control is the minimum inhibitory concentration of the sample for the bacteria. The bacterial solutions at the inhibitory concentrations are evenly spread on the MH plate, and the plate is inverted and cultured in a 37℃ incubator for 18-24h. The minimum drug concentration without colony growth is the minimum bactericidal concentration of the drug for the bacteria.

[0061] (3) Chessboard method combined with drug sensitivity test:

[0062] Take out the sterilized 96-well plate and use the chessboard method to add 50 μL of the two drugs at the above concentrations in the horizontal and vertical columns of the 96-well plate. Place the two drug mixtures with different concentrations in each well. Add 100 μL of the diluted 10 6CFU / mL bacterial suspension was cultured in a 37°C incubator for 24 h. After the culture, the absorbance value of each well of the 96-well plate was measured using an ELISA reader, and the chessboard test was repeated 3 times.

[0063] Example 2

[0064] (1) Preparation of zinc oxide nanoparticles / ionic liquids:

[0065] ZnO nanoparticles were suspended in ionic liquid / deionized water and ultrasonically treated for 5 min. The ratio of ionic liquid to water was 10 mmol:1 L, and the ratio of zinc oxide nanoparticles to water was 12, 24, 36, and 48 mg:100 mL, respectively, to obtain a ZnO / IL dispersion solution.

[0066] (2) Preparation and characterization of microneedle patches:

[0067] I. Dissolve MeHA (100 mg / mL) and HCPK (0.5 mg / mL) in ZnO / IL dispersion solutions of different concentrations and mix them evenly. Pipette 500 μL of the mixed solution and drop it into the PDMS microneedle mold. Centrifuge at 3000 r / min for 10 min to remove bubbles. After centrifugation, irradiate the mold with a UV lamp at a wavelength of 365 nm for 2 min, take it out and dry it at room temperature for 24 h. Take the microneedle patch out of the mold and dry it at room temperature for 24 h.

[0068] II. Observation of microneedle patch morphology: The morphology of the microneedle patch array was observed using a camera, an optical microscope, and a scanning electron microscope. The dispersion of zinc oxide nanoparticles in the microneedles was also observed using a scanning electron microscope.

[0069] III. Puncture ability of microneedle patch: The puncture performance of microneedle patch was investigated using in vitro pig skin. After thawing the pig skin, the surface moisture was removed with filter paper, and then the skin was spread on the filter paper with the stratum corneum facing outward. It was pressed vertically for 30 seconds with a certain intensity, and the microneedle patch was pulled out. Then it was stained with a certain concentration of trypan blue solution for 10 minutes, and the trypan blue solution on the surface of the skin was removed. Then the stained skin was observed and photographed, and the holes left on the surface of the pig skin were counted and the puncture rate was calculated to be about 99%, indicating good mechanical properties. The puncture rate was calculated according to the following formula:

[0070]

[0071] A recorded is the number of pinholes recorded; A original is the number of original microneedle tips.

[0072] IV. Healing ability of microneedle patch: The skin healing of the puncture site after microneedle patch skin puncture was evaluated by conducting experiments on rat skin. After SD rats were raised normally for 14 days, most of the longer hair of the rats were cut off with scissors, and then the depilatory cream was evenly applied to the skin of the rat's back for 3 minutes. The application time was appropriately extended or shortened according to the situation to avoid burning the rat's skin. Finally, the depilatory cream and shed hair were wiped clean with warm water, and the back of the rat was observed. When the rat's skin condition was relatively good, the microneedle patch was vertically inserted into the skin of the rat's back with appropriate force. After 30 seconds, the patch was removed. A clear 11*11 micropore array appeared on the skin surface. At the same time, a camera was used to take pictures at different time points to record the healing process of the skin. It can be seen from the figure that as time goes on, the micropores formed by the microneedle patch in the skin gradually heal and disappear within 10 minutes. It was observed that there were no adverse reactions such as redness, swelling and inflammation on the surface of the rat's skin, and the healing condition was good.

[0073] V. Investigation of the solubility of microneedle patches: The microneedle patches were inserted into the skin of rats, and the dissolution of the needle tip was observed under a microscope after different time periods to investigate the dissolution of the microneedle patches in vivo. The dissolution of the microneedle tips after being inserted into the rats for different lengths of time was observed from the optical microscope images. It can be seen that the microneedle patches can dissolve within 10 minutes after being inserted into the intact skin of rats, thereby achieving rapid local drug delivery.

[0074] VI. Investigation of blood compatibility of microneedle patches: A methacrylic anhydride hyaluronic acid precursor solution containing zinc oxide nanoparticles / ionic liquid dispersions of different concentrations for the manufacture of microneedle patches was prepared, and the precursor solution was extracted with physiological saline to obtain extracts of different concentrations, and the extracts were filtered through a 0.22 μm filter membrane. Then, the solution after the filter membrane was incubated with rat red blood cells (RBC, 2% v / v) at a constant temperature of 37°C for 1 hour. The suspension treated with physiological saline was used as a negative control, while the suspension treated with Wahaha water was used as a positive control. Three replicate samples were provided for each group. After the incubation was completed, the incubation was centrifuged at 13000 rpm for 5 minutes, and the OD value of the supernatant was measured at 545 nm. The formula for calculating the hemolysis rate is as follows:

[0075]

[0076] The hemolysis rate of the prepared soluble antibacterial microneedle patch is much less than 5%, and has good blood compatibility.

[0077] VII. In vitro antibacterial study of microneedle patches:

[0078] Co-culture: Prepare microneedle patches of different concentrations and use the plate count method to detect the antibacterial activity of the microneedle patches. Take a quarter of the microneedle patch and add it to 100 μL of bacterial suspension (10 6CFU / mL), and then add 500μL of physiological saline to prevent the microneedle patch from being unable to absorb water and dissolve to release the antibacterial agent. The mixture was co-cultured in a 48-well plate at 37℃ for 24h. Then, 10μL of the diluted bacterial suspension was applied to the MH culture dish, and after culturing at 37℃ for 24h, the number of colonies in each plate was counted.

[0079] Growth curve: The antibacterial test was conducted by immersing the microneedle patch loaded with different concentrations of zinc oxide nanoparticles / ionic liquid into Staphylococcus aureus and Escherichia coli culture to evaluate the antibacterial performance of the microneedle patch. The experimental group was a microneedle patch with different concentrations of zinc oxide nanoparticles / ionic liquid immersed in a bacterial culture solution, while the control group was only a bacterial culture solution. The Escherichia coli and Staphylococcus aureus suspensions were co-cultured with the microneedle patches of the experimental group in a 37°C constant temperature shaker, and the optical density (OD 600) of the cultured bacteria was measured at different times to draw a growth curve.

[0080] VIII. Investigation of the in vivo antibacterial property of the microneedle patch: In order to further explore the practical value of the microneedle patch in antibacterial properties, we established a rat model of infected skin injury. The rats were depilated and a wound of about 1 square centimeter was cut on the skin on the back of the rats. 10 μL of bacterial solution was applied to the wound for 1 minute, and then scrubbed with saline for 1 minute to complete the establishment of the wound model. Rats that were not treated with microneedle patches were the control group, and rats that were treated with microneedle patches were the experimental group (n=3). All mice were raised under the same conditions, and the wound healing status was recorded at different times. The wound healing status was judged based on the wound healing rate and the wound tissue staining sections on the 15th day.

Claims

1. An integrated soluble microneedle, characterized in that: The soluble microneedle is obtained by injecting a precursor solution into a PDMS mold, centrifuging until the solution fills the needle tip, and placing the centrifuged microneedle under an ultraviolet lamp for cross-linking, wherein the precursor solution is composed of a matrix, a photoinitiator, and a zinc oxide nanoparticle / ionic liquid dispersion with synergistic antibacterial properties, and the ratio of the dispersion to the matrix in the precursor solution is 1 mL: 60-120 mg; the photoinitiator is 1-hydroxycyclohexyl phenyl ketone (HCPK), and the ratio of HCPK to the dispersion is 1 mg: 2 mL. The dispersion is composed of zinc oxide nanoparticles, 1-butyl-3-methylimidazolium chloride ionic liquid and water, wherein the ratio of ionic liquid to water in the dispersion is 10 mmol:1L; the ratio of zinc oxide nanoparticles to water in the dispersion is 12-48 mg:100 mL; the matrix is ​​methacrylated hyaluronic acid, and the grafting rate is 12%-22%; the size of the zinc oxide nanoparticles is 50±10 nm; The matrix methacrylated hyaluronic acid is prepared by the following method: methacrylic anhydride and hyaluronic acid are mixed at a temperature below 4°C and the pH is maintained between 8 and 9 for reaction, wherein the molecular weight of the hyaluronic acid is 100 kDa to 400 kDa; and the molar ratio of methacrylic anhydride to hyaluronic acid is 3 to 10:

1.

2. The integrated soluble microneedle according to claim 1, characterized in that: The dispersion is composed of zinc oxide nanoparticles dispersed in 1-butyl-3-methylimidazolium chloride ionic liquid / water solvent.

3. The integrated soluble microneedle according to claim 1, characterized in that: The dispersion is prepared by the following method: preparing an ionic liquid / water solvent of a certain concentration, and uniformly dispersing zinc oxide nanoparticles in the ionic liquid / water solvent by ultrasound.

4. The microneedle according to claim 1, characterized in that: The precursor solution also contains medical antibacterial agents or medical cosmetic ingredients.

5. The method for preparing the integrated soluble microneedle according to claim 1, characterized in that: Dissolve methacrylated hyaluronic acid and HCPK in zinc oxide nanoparticle / ionic liquid dispersion, stir evenly, and let stand to remove bubbles to obtain a microneedle precursor solution; inject the microneedle precursor solution into a PDMS mold, and centrifuge until the solution fills the needle tip; The centrifuged microneedles were placed under UV light for cross-linking; after cross-linking, they were dried for 24 h; The needle body of the PDMS mold is in the shape of a quadrangular pyramid or a cone, and the needle length is 600-1000 μm; the centrifugal speed is 3000-4000 rpm, and the centrifugal time is 5-20 min; the cross-linking time is 30 s-5 min; and the drying condition is room temperature drying.

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