Hydrogel microneedle dressing as well as preparation method and application thereof

Abstract

The invention relates to the technical field of medical biological materials, and discloses a hydrogel microneedle dressing as well as a preparation method and application thereof. The hydrogel microneedle dressing comprises a substrate and a hydrogel needle tip positioned on the substrate, the hydrogel needle tip is prepared from the following raw materials in parts by weight: 20 to 40 parts of oxidized hyaluronic acid, 20 to 40 parts of carboxymethyl chitosan, 2 to 16 parts of iron-loaded ZIF-8 nanoparticles, 1 to 2 parts of glucose oxidase and 402 to 457 parts of water. The preparation method comprises the following steps: carrying out Schiff base reaction on carboxymethyl chitosan and oxidized hyaluronic acid to prepare hydrogel; loading the iron-loaded ZIF-8 nanoparticles and glucose oxidase on the hydrogel to obtain a needle tip precursor solution; and preparing the hydrogel microneedle dressing from the needle tip precursor solution and the substrate precursor solution through a hydrogel microneedle dressing forming process. The hydrogel microneedle dressing is used for preparing medical skin wound dressing, and the antibacterial effect under response of the internal environment is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical biomaterials, and in particular relates to a hydrogel microneedle dressing and a preparation method and application thereof. Background Art

[0002] Clinically, for the treatment of chronic diabetic wounds, it is usually necessary to bandage the wound with gauze after debridement, in order to absorb exudate, fix the wound, and prevent foreign objects from touching it. However, gauze, as the most basic wound dressing, has many disadvantages, such as easy adhesion to the wound causing secondary damage, failure to provide a moist environment, failure to ensure the sterility of the wound surface, and poor wound healing effect; therefore, it is necessary to develop more functional wound dressings to cover the wound and provide a temporary barrier to external infection. Reactive oxygen has strong oxidizing properties and can have a good killing effect on bacteria while preventing bacteria from developing drug resistance. Therefore, more and more researchers are applying it to the field of antibacterial.

[0003] Many dressings with antibacterial effects are disclosed in the prior art. For example, Angew.Chem.Int.Ed.2019,58,4911-4916 discloses an inorganic nano antibacterial material similar to horseradish catalase. When the material acts on the wound surface, it can decompose hydrogen peroxide to produce active oxygen under the condition of adding hydrogen peroxide solution, thereby achieving an antibacterial effect.

[0004] For diabetics, in addition to bacterial infection, abnormal blood sugar concentration is also an important reason why chronic wounds of diabetic patients are difficult to heal. The inorganic nano antibacterial material not only requires the addition of hydrogen peroxide solution, but also cannot control blood sugar concentration. Therefore, it is urgent to develop a wound dressing that does not require the addition of hydrogen peroxide solution and can reduce the blood sugar concentration of diabetic patients. Summary of the invention

[0005] The present invention provides a hydrogel microneedle dressing and a preparation method and application thereof, which solves the problem that the inorganic nano antibacterial material prepared by the prior art not only needs to add additional hydrogen peroxide solution but also cannot control the blood sugar concentration.

[0006] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0007] The raw materials of the hydrogel needle tip include, by weight: 20-40 parts of oxidized hyaluronic acid, 20-40 parts of carboxymethyl chitosan, 2-16 parts of iron-loaded ZIF-8 nanoparticles, 1-2 parts of glucose oxidase, and 402-457 parts of water.

[0008] Preferably, the raw materials of the hydrogel needle tip include, by weight: 25-35 parts of oxidized hyaluronic acid, 25-35 parts of carboxymethyl chitosan, 6-10 parts of iron-loaded ZIF-8 nanoparticles, 1-2 parts of glucose oxidase, and 422-437 parts of water.

[0009] Preferably, the raw materials of the hydrogel needle tip include, by weight: 30 parts of oxidized hyaluronic acid, 30 parts of carboxymethyl chitosan, 8 parts of iron-loaded ZIF-8 nanoparticles, 2 parts of glucose oxidase, and 430 parts of water.

[0010] The second object of the present invention is to provide a method for preparing the hydrogel microneedle dressing, comprising:

[0011] Dissolving the formulated amount of iron-loaded ZIF-8 nanoparticles and glucose oxidase in water to obtain a precursor solution;

[0012] The hydrogel needle tip precursor is obtained by dissolving the formulated amount of carboxymethyl chitosan and oxidized hyaluronic acid with the precursor solution;

[0013] The hydrogel microneedle dressing is prepared by subjecting the hydrogel needle tip precursor and the precursor solution of the substrate to a hydrogel microneedle dressing molding process.

[0014] Preferably, the preparation method of the iron-loaded ZIF-8 nanoparticles is:

[0015] After the ZIF-8 nanoparticles are dispersed, tannic acid and ferric chloride are added, and the mixture is stirred for 10 minutes in the dark; and the iron-loaded ZIF-8 nanoparticles are obtained by centrifugation.

[0016] Preferably, the mass ratio of the ZIF-8 nanoparticles, tannic acid and ferric chloride is 100-200:4-8:4-8.

[0017] Preferably, the synthesis method of the oxidized hyaluronic acid is:

[0018] After the hyaluronic acid is dissolved, sodium periodate solution is added and stirred in the dark for 2 hours; after quenching, the mixture is stirred for another hour, dialyzed and freeze-dried to obtain oxidized hyaluronic acid.

[0019] Preferably, the mass ratio of hyaluronic acid to sodium periodate is 2:1.072.

[0020] Preferably, the hydrogel microneedle dressing molding process includes:

[0021] The hydrogel needle tip precursor is cast on a PDMS template, and after centrifugation, the excess solution on the surface of the PDMS mold is scraped off, and then the precursor solution of the substrate is added, and the mixture is centrifuged again, dried, and demolded to obtain the hydrogel microneedle dressing.

[0022] Preferably, the precursor solution of the substrate is a hyaluronic acid solution.

[0023] Preferably, the concentration of the hyaluronic acid solution is 40-80 mg / mL.

[0024] The centrifugal speed is 3000 r / min and the time is 5 min. The drying conditions are: room temperature, relative humidity of 3.5%, and drying for 24 h.

[0025] The microneedle comprises a quadrangular pyramid microneedle tip, the height of the microneedle tip is 1450 μm, and the microneedle tips are distributed on one side of the microneedle substrate in a 10×10 array. The bottom radius of the microneedle tip is 580 μm, and the tip spacing of the microneedle tip is 1250 μm. The thickness of the microneedle substrate is 300 μm.

[0026] The third object of the present invention is to protect the use of the hydrogel microneedle dressing in the preparation of medical skin wound dressings.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The hydrogel microneedle dressing provided by the present invention is prepared by compounding oxidized hyaluronic acid, carboxymethyl chitosan, iron-loaded ZIF-8 nanoparticles and glucose oxidase. When the needle tip of the hydrogel microneedle dressing is inserted into the skin infected with bacteria, since the substance secreted by the bacteria is acidic, the hydrogel formed by the Schiff base will quickly dissolve in an acidic environment, releasing glucose oxidase, iron-loaded ZIF-8 nanoparticles, carboxymethyl chitosan and oxidized hyaluronic acid: on the one hand, the glucose oxidase reacts with glucose in the internal environment to generate hydrogen peroxide and acidic gluconic acid, and the gluconic acid forms a slightly acidic environment in the local wound, which promotes the iron-loaded ZIF -8 nanoparticles disintegrate, releasing zinc ions and iron ions; the Fenton reaction of iron ions and hydrogen peroxide can produce toxic hydroxyl radicals around bacteria, causing bacteria to lyse and die from the inside out, achieving the antibacterial effect under the response of the internal environment, and the hydrogel microneedle dressing provided by the present invention, its needle tip can directly release iron ions, rather than iron-containing compounds, so it is easier to play a role and has a higher sterilization efficiency; on the other hand, carboxymethyl chitosan has good water solubility in a wide pH range, good biocompatibility, promotes wound healing, analgesic effect, antibacterial and anti-infection, and hypoglycemic effect; the released oxidized hyaluronic acid and carboxymethyl chitosan can also promote wound healing. On the third aspect, since the hydrogel microneedle dressing provided by the present invention consumes glucose in the internal environment during the reaction, it can reduce the local blood sugar concentration while killing bacteria, improve the wound environment, and reduce factors that are not conducive to wound healing. Therefore, the hydrogel microneedle dressing provided by the present invention, sterilization and promotion of wound healing jointly promote wound healing, and at the same time, reduce the blood sugar concentration of diabetic patients, and the wound healing effect on diabetic patients is obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 SEM images of ZIF-8 and ZIF-8@Fe provided in Example 1 of the present invention;

[0030] Figure 2 This is a common optical photograph of the hydrogel microneedle dressing provided in Example 1 of the present invention;

[0031] Figure 3 This is a scanning electron microscope photo of the hydrogel microneedle dressing provided in Example 1 of the present invention;

[0032] Figure 4 This is an antibacterial optical picture of the hydrogel microneedle dressing provided in Example 1 of the present invention;

[0033] Figure 5 The antibacterial rate of the hydrogel microneedle dressing provided in Example 1 of the present invention;

[0034] Figure 6 This is a TEM scanning image of the hydrogel microneedle dressing provided in Example 1 of the present invention;

[0035] Figure 7 This is a verification of the cascade mechanism of the hydrogel microneedle dressing provided in Example 1 of the present invention. DETAILED DESCRIPTION

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

[0037] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0038] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. Among them, A and B can be singular or plural; the single symbol " / " means "or".

[0039] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of A, B or C", or "at least one of A, B and C" can represent any one of A, B, C, or A+B, or A+C, or B+C, or A+B+C, where A, B, C can be single or multiple, respectively.

[0040] In the following description of this embodiment, the order of serial numbers does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this embodiment.

[0041] In the following description of the present embodiment, the numerical range should be understood to also specifically disclose each intermediate value between the upper and lower limits of the range. Any stated value or intermediate value in the stated range and any other stated value or each smaller range between the intermediate values ​​in the stated range are also included in the present embodiment, and the upper and lower limits of the smaller range can be independently included or excluded in the range.

[0042] Unless otherwise stated, the technical / scientific terms used in the present embodiment have the same meanings as those generally understood by those skilled in the art to which the present application belongs. Although the present application only describes preferred methods and materials, any similar or equivalent methods and materials may also be used in the implementation or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

[0043] Abbreviations of some substances in the embodiments of the present invention:

[0044] Dimethylimidazole: 2-MIM, oxidized hyaluronic acid: OHA, carboxymethyl chitosan: CMCS, glucose oxidase: GOX, tannic acid: TA, hyaluronic acid: HA.

[0045] Example 1

[0046] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0047] The raw materials in the hydrogel needle tip include, by weight: 2 parts of iron-loaded ZIF-8 nanoparticles, 20 parts of oxidized hyaluronic acid, 20 parts of carboxymethyl chitosan, 1 part of glucose oxidase, and 402 parts of water.

[0048] A method for preparing a hydrogel microneedle dressing, comprising:

[0049] (1) Preparation of ZIF-8@Fe nanoparticles: Dissolve 325 mg of dimethylimidazole in 10 mL of methanol, and vibrate ultrasonically at room temperature for 30 minutes until a uniform dimethylimidazole solution is formed. Dissolve 147 mg of zinc nitrate hexahydrate in 5 ml of methanol, and vibrate ultrasonically at room temperature for 5 minutes until a uniform zinc nitrate solution is formed. Finally, add the dimethylimidazole solution dropwise into the zinc nitrate solution, and stir the mixed solution vigorously at 37°C for half an hour; centrifuge three times to remove unreacted substances, and dry to obtain ZIF-8 nanoparticles. Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, and immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution. Stir in the dark for 10 minutes to allow tannic acid and Fe to react. 3+ It can be chelated evenly on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0050] (2) Synthesis of oxidized hyaluronic acid

[0051] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate was replaced 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0052] (3) Preparation of hydrogel needle tip precursor

[0053] The formulated amounts of iron-loaded ZIF-8 nanoparticles and glucose oxidase are dissolved in water to obtain a precursor solution.

[0054] The precursor solution is used to dissolve the formulated amounts of carboxymethyl chitosan and oxidized hyaluronic acid to obtain a hydrogel needle tip precursor.

[0055] Through precise calculation of the PDMS mold, the total volume of the needle tip = 1 / 3 × 0.145 × 0.0582 × 10 × 10 = 0.01626 mL.

[0056] (4) Preparation of hydrogel microneedle dressing

[0057] It was prepared by a high-speed centrifugation two-step template method, specifically, the hydrogel needle tip precursor was cast on the PDMS template, centrifuged at a speed of 3000r / min for 5min, so that it could fully fill the cavity of the template, and after the centrifugation, the excess hydrogel needle tip precursor on the surface of the PDMS mold was scraped off, and a HA microneedle substrate solution with a concentration of 40mg / mL was added to compound, so that the solution could fully fill the cavity of the template, and after the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold was scraped off, and finally dried in a drying oven for 24h, and demolded to obtain the hydrogel microneedle dressing, which was recorded as GZIF@Fe MN.

[0058] Instructions for use: Insert the prepared microneedle tip into the bacterially infected skin. The Schiff base hydrogel formed by the microneedle tip matrix components (oxidized hyaluronic acid and carboxymethyl chitosan) will quickly dissolve in the acidic substances secreted by the bacteria, releasing a certain amount of glucose oxidase encapsulated. Glucose oxidase reacts with glucose in the internal environment to generate hydrogen peroxide and acidic gluconic acid. Gluconic acid creates a slightly acidic environment in the local wound, which promotes the disintegration of nanoparticles and releases zinc ions and iron ions. The iron ions and hydrogen peroxide undergo a Fenton reaction to produce toxic hydroxyl radicals around the bacteria, which break down and die from the inside out, achieving an antibacterial effect. Oxidized hyaluronic acid and carboxymethyl chitosan can also synergistically promote wound healing.

[0059] Example 2

[0060] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0061] The raw materials in the hydrogel needle tip include, by weight: 6 parts of iron-loaded ZIF-8 nanoparticles, 25 parts of oxidized hyaluronic acid, 25 parts of carboxymethyl chitosan, 1 part of glucose oxidase, and 422 parts of water.

[0062] A method for preparing a hydrogel microneedle dressing, comprising:

[0063] (1) Preparation of ZIF-8@Fe nanoparticles: Dissolve 325 mg of dimethylimidazole in 10 mL of methanol, and vibrate ultrasonically at room temperature for 30 minutes until a uniform dimethylimidazole solution is formed. Dissolve 147 mg of zinc nitrate hexahydrate in 5 ml of methanol, and vibrate ultrasonically at room temperature for 5 minutes until a uniform zinc nitrate solution is formed. Finally, add the dimethylimidazole solution dropwise into the zinc nitrate solution, and stir the mixed solution vigorously at 37°C for half an hour; centrifuge three times to remove unreacted substances, and dry to obtain ZIF-8 nanoparticles. Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, and immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution. Stir in the dark for 10 minutes to allow TA and Fe to react. 3+ It can be uniformly chelated on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0064] (2) Synthesis of oxidized hyaluronic acid

[0065] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate is replaced at least 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0066] (3) Preparation of hydrogel needle tip precursor

[0067] The formulated amounts of iron-loaded ZIF-8 nanoparticles and glucose oxidase are dissolved in water to obtain a precursor solution.

[0068] The precursor solution is used to dissolve the formulated amounts of carboxymethyl chitosan and oxidized hyaluronic acid to obtain a hydrogel needle tip precursor.

[0069] Through precise calculation of the PDMS mold, the total volume of the needle tip = 1 / 3 × 0.145 × 0.0582 × 10 × 10 = 0.01626 mL.

[0070] (4) Preparation of microneedles

[0071] It is prepared by a high-speed centrifugation two-step template method, specifically, the hydrogel needle tip precursor is cast on the PDMS template, centrifuged at a speed of 3000r / min for 5min, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess hydrogel needle tip precursor on the surface of the PDMS mold is scraped off, and a HA microneedle substrate solution with a concentration of 50mg / mL is added to compound, allowing the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold is scraped off, and finally dried in a drying oven for 24h, and the hydrogel microneedle dressing is obtained by demolding.

[0072] Example 3

[0073] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0074] The raw materials in the hydrogel needle tip include, by weight: 8 parts of iron-loaded ZIF-8 nanoparticles, 30 parts of oxidized hyaluronic acid, 30 parts of carboxymethyl chitosan, 2 parts of glucose oxidase, and 430 parts of water.

[0075] A method for preparing a hydrogel microneedle dressing, comprising:

[0076] (1) Preparation of ZIF-8@Fe nanoparticles: Dissolve 325 mg of dimethylimidazole in 10 mL of methanol, and vibrate ultrasonically at room temperature for 30 minutes until a uniform dimethylimidazole solution is formed. Dissolve 147 mg of zinc nitrate hexahydrate in 5 ml of methanol, and vibrate ultrasonically at room temperature for 5 minutes until a uniform zinc nitrate solution is formed. Finally, add the dimethylimidazole solution dropwise into the zinc nitrate solution, and stir the mixed solution vigorously at 37°C for half an hour; centrifuge three times to remove unreacted substances, and dry to obtain ZIF-8 nanoparticles. Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, and immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution. Stir in the dark for 10 minutes to allow TA and Fe to react. 3+It can be uniformly chelated on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0077] (2) Synthesis of oxidized hyaluronic acid

[0078] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate is replaced at least 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0079] (3) Preparation of hydrogel needle tip precursor

[0080] The formulated amounts of iron-loaded ZIF-8 nanoparticles and glucose oxidase are dissolved in water to obtain a precursor solution.

[0081] The precursor solution is used to dissolve the formulated amounts of carboxymethyl chitosan and oxidized hyaluronic acid to obtain a hydrogel needle tip precursor.

[0082] Through precise calculation of the PDMS mold, the total volume of the needle tip = 1 / 3 × 0.145 × 0.0582 × 10 × 10 = 0.01626 mL.

[0083] (4) Preparation of microneedles

[0084] It is prepared by a high-speed centrifugation two-step template method, specifically, the hydrogel needle tip precursor is cast on the PDMS template, centrifuged at a speed of 3000r / min for 5 minutes, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess hydrogel needle tip precursor on the surface of the PDMS mold is scraped off, and a HA microneedle substrate solution with a concentration of 60mg / mL is added to compound, allowing the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold is scraped off, and finally dried in a drying oven for 24h, and the hydrogel microneedle dressing is obtained by demolding.

[0085] Example 4

[0086] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0087] The raw materials in the hydrogel needle tip include, by weight: 10 parts of iron-loaded ZIF-8 nanoparticles, 35 parts of oxidized hyaluronic acid, 35 parts of carboxymethyl chitosan, 2 parts of glucose oxidase, and 437 parts of water.

[0088] A method for preparing a hydrogel microneedle dressing, comprising:

[0089] (1) Preparation of ZIF-8@Fe nanoparticles: Dissolve 325 mg of dimethylimidazole in 10 mL of methanol, and vibrate ultrasonically at room temperature for 30 minutes until a uniform dimethylimidazole solution is formed. Dissolve 147 mg of zinc nitrate hexahydrate in 5 ml of methanol, and vibrate ultrasonically at room temperature for 5 minutes until a uniform zinc nitrate solution is formed. Finally, add the dimethylimidazole solution dropwise into the zinc nitrate solution, and stir the mixed solution vigorously at 37°C for half an hour; centrifuge three times to remove unreacted substances, and dry to obtain ZIF-8 nanoparticles. Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, and immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution. Stir in the dark for 10 minutes to allow TA and Fe to react. 3+ It can be uniformly chelated on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0090] (2) Synthesis of oxidized hyaluronic acid

[0091] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate is replaced at least 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0092] (3) Preparation of hydrogel needle tip

[0093] The formulated amounts of iron-loaded ZIF-8 nanoparticles and glucose oxidase are dissolved in water to obtain a precursor solution.

[0094] The precursor solution is used to dissolve the formulated amounts of carboxymethyl chitosan and oxidized hyaluronic acid to obtain a hydrogel needle tip precursor.

[0095] Through precise calculation of the PDMS mold, the total volume of the needle tip = 1 / 3 × 0.145 × 0.0582 × 10 × 10 = 0.01626 mL.

[0096] (4) Preparation of microneedles

[0097] It is prepared by a high-speed centrifugation two-step template method, specifically, the hydrogel needle tip precursor is cast on the PDMS template, centrifuged at a speed of 3000r / min for 5 minutes, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess hydrogel needle tip precursor on the surface of the PDMS mold is scraped off, and a HA microneedle substrate solution with a concentration of 70mg / mL is added to compound, allowing the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold is scraped off, and finally dried in a drying oven for 24h, and the hydrogel microneedle dressing is obtained by demolding.

[0098] Example 5

[0099] A hydrogel microneedle dressing, comprising a substrate and a hydrogel needle tip located on the substrate;

[0100] The raw materials in the hydrogel needle tip include, by weight: 16 parts of iron-loaded ZIF-8 nanoparticles, 40 parts of oxidized hyaluronic acid, 40 parts of carboxymethyl chitosan, 2 parts of glucose oxidase, and 457 parts of water.

[0101] A method for preparing a hydrogel microneedle dressing, comprising:

[0102] (1) Preparation of ZIF-8@Fe nanoparticles: Dissolve 325 mg of dimethylimidazole in 10 mL of methanol, and vibrate ultrasonically at room temperature for 30 minutes until a uniform dimethylimidazole solution is formed. Dissolve 147 mg of zinc nitrate hexahydrate in 5 ml of methanol, and vibrate ultrasonically at room temperature for 5 minutes until a uniform zinc nitrate solution is formed. Finally, add the dimethylimidazole solution dropwise into the zinc nitrate solution, and stir the mixed solution vigorously at 37°C for half an hour; centrifuge three times to remove unreacted substances, and dry to obtain ZIF-8 nanoparticles. Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, and immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution. Stir in the dark for 10 minutes to allow TA and Fe to react. 3+ It can be uniformly chelated on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0103] (2) Synthesis of oxidized hyaluronic acid

[0104] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate is replaced at least 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0105] (3) Preparation of hydrogel needle tip

[0106] The formulated amounts of iron-loaded ZIF-8 nanoparticles and glucose oxidase are dissolved in water to obtain a precursor solution.

[0107] The precursor solution is used to dissolve the formulated amounts of carboxymethyl chitosan and oxidized hyaluronic acid to obtain a hydrogel needle tip precursor.

[0108] Through precise calculation of the PDMS mold, the total volume of the needle tip = 1 / 3 × 0.145 × 0.0582 × 10 × 10 = 0.01626 mL.

[0109] (4) Preparation of hydrogel microneedle dressing

[0110] It is prepared by a high-speed centrifugation two-step template method, specifically, the hydrogel needle tip precursor liquid is cast on the PDMS template, centrifuged at a speed of 3000r / min for 5min, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess hydrogel needle tip precursor on the surface of the PDMS mold is scraped off, and an HA microneedle substrate solution with a concentration of 80mg / mL is added to compound, allowing the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold is scraped off, and finally dried in a drying oven for 24h, and the hydrogel microneedle dressing is obtained by demolding.

[0111] Comparative Example 1 (ZIF-8MN)

[0112] A method for preparing a microneedle, comprising:

[0113] (1) 325 mg of dimethylimidazole was dissolved in 10 mL of methanol, and ultrasonic vibration was applied at room temperature for 30 min until a uniform dimethylimidazole solution was formed. 147 mg of zinc nitrate hexahydrate was dissolved in 5 mL of methanol, and ultrasonic vibration was applied at room temperature for 5 min until a uniform zinc nitrate solution was formed. Finally, the dimethylimidazole solution was added dropwise to the zinc nitrate solution, and the mixed solution was vigorously stirred at 37° C. for half an hour; the mixture was centrifuged three times to remove unreacted substances, and dried to obtain ZIF-8 nanoparticles.

[0114] (2) ZIF-8 nanoparticles were prepared into a solution with a concentration of 4 mg / mL, cast on a PDMS template, and centrifuged at a speed of 3000 r / min for 5 min to allow the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle tip precursor solution on the surface of the PDMS mold was scraped off, and a 40 mg / mL HA microneedle substrate solution was added to compound to allow the solution to fully fill the cavity of the template. After the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold was scraped off, and finally dried in a drying oven for 24 h. The microneedles were demolded to obtain ZIF-8MN.

[0115] Comparative Example 2 (ZIF-8@Fe MN)

[0116] A method for preparing a microneedle, comprising:

[0117] (1) 325 mg of dimethylimidazole was dissolved in 10 mL of methanol, and ultrasonic vibration was applied at room temperature for 30 min until a uniform dimethylimidazole solution was formed. 147 mg of zinc nitrate hexahydrate was dissolved in 5 mL of methanol, and ultrasonic vibration was applied at room temperature for 5 min until a uniform zinc nitrate solution was formed. Finally, the dimethylimidazole solution was added dropwise to the zinc nitrate solution, and the mixed solution was vigorously stirred at 37° C. for half an hour; the mixture was centrifuged three times to remove unreacted substances, and dried to obtain ZIF-8 nanoparticles.

[0118] (2) Disperse 10 mg of ZIF-8 nanoparticles in 10 mL of ethanol, immediately add 20 μL of 40 mg / mL TA solution and 40 μL of 10 mg / mL ferric chloride hexahydrate solution, and stir for 10 min in the dark to allow TA and Fe to react. 3+ It can be uniformly chelated on ZIF-8 nanoparticles. Finally, after centrifugation at 10000 rpm for 10 min and repeated washing with deionized water three times to fully remove TA and ferric chloride hexahydrate, ZIF-8 nanoparticles loaded with iron, namely ZIF-8@Fe nanoparticles, were obtained.

[0119] (3) ZIF-8@Fe nanoparticles were prepared into a solution with a concentration of 4 mg / mL, cast on a PDMS template, and centrifuged at a speed of 3000 r / min for 5 min to allow the solution to fully fill the cavity of the template. After centrifugation, the excess microneedle tip precursor solution on the surface of the PDMS mold was scraped off, and a 40 mg / mL HA microneedle substrate solution was added to compound to allow the solution to fully fill the cavity of the template. After centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold was scraped off, and finally dried in a drying oven for 24 h. The microneedles were demolded to obtain ZIF-8@Fe MN.

[0120] Comparative Example 3 (ZIF-8@GOX MN)

[0121] A method for preparing a microneedle, comprising:

[0122] (1) 325 mg of dimethylimidazole was dissolved in 10 mL of methanol, and ultrasonic vibration was applied at room temperature for 30 min until a uniform dimethylimidazole solution was formed. 147 mg of zinc nitrate hexahydrate was dissolved in 5 mL of methanol, and ultrasonic vibration was applied at room temperature for 5 min until a uniform zinc nitrate solution was formed. Finally, the dimethylimidazole solution was added dropwise to the zinc nitrate solution, and the mixed solution was vigorously stirred at 37° C. for half an hour; the mixture was centrifuged three times to remove unreacted substances, and dried to obtain ZIF-8 nanoparticles.

[0123] (2) Dissolve 2 mg of glucose oxidase in 1 ml of water to obtain a glucose oxidase solution. Dissolve 4 mg of ZIF-8 nanoparticles in 1 ml of water to obtain a ZIF-8 nanoparticle solution. Mix the obtained glucose oxidase solution and ZIF-8 nanoparticle solution and cast them on a PDMS template. Centrifuge at a speed of 3000 r / min for 5 min to allow the solution to fully fill the cavity of the template. After centrifugation, scrape off the excess microneedle tip precursor solution on the surface of the PDMS mold, add 40 mg / mL HA microneedle substrate solution to compound, and allow the solution to fully fill the cavity of the template. After centrifugation, scrape off the excess microneedle substrate solution on the surface of the PDMS mold, and finally dry it in a drying oven for 24 hours. Demolding to obtain microneedles is recorded as ZIF-8@GOX MN.

[0124] Comparative Example 4 (B MN)

[0125] A method for preparing a microneedle, comprising:

[0126] (1) Synthesis of oxidized hyaluronic acid

[0127] Weigh 2g HA and dissolve it in 200mL deionized water, i.e., the concentration is 10mg / mL, and stir to completely dissolve it; dissolve 1.072g sodium periodate in 2.5mL deionized water, i.e., the concentration is 0.5mol / L, and then add it dropwise to the above HA solution, and stir in the dark for 2h; then quench the unreacted sodium periodate with 1mL ethylene glycol, and stir for another 1h; after the reaction, the solution is transferred to a dialysis bag (molecular weight cutoff 8-14KD), dialyzed in deionized water for 3 days, the dialysate was replaced 3 times a day, and finally freeze-dried for 2 days to obtain oxidized hyaluronic acid.

[0128] (2) Preparation of microneedle tip precursor solution

[0129] A formulated amount of oxidized hyaluronic acid is added to a formulated amount of carboxymethyl chitosan solution, and the mixture is stirred and blended to obtain a microneedle tip precursor solution.

[0130] (3) Preparation of microneedles

[0131] It was prepared by a high-speed centrifugation two-step template method, specifically, the microneedle tip precursor solution was cast on the PDMS template, centrifuged at a speed of 3000r / min for 5min, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess microneedle tip precursor solution on the surface of the PDMS mold was scraped off, and a HA microneedle substrate solution with a concentration of 40mg / mL was added to compound, allowing the solution to fully fill the cavity of the template, and after the centrifugation, the excess microneedle substrate solution on the surface of the PDMS mold was scraped off, and finally dried in a drying oven for 24h. The microneedles were demolded and recorded as B MN.

[0132] The performance of the hydrogel microneedle dressing prepared in Examples 2 to 5 of the present invention is substantially the same as that of the hydrogel microneedle dressing prepared in Example 1. The following test is conducted by taking the hydrogel microneedle dressing prepared in Example 1 as an example.

[0133] Performance Testing:

[0134] 1 Characterization Test

[0135] Figure 1 The SEM images of ZIF-8 and ZIF-8@Fe provided in Example 1 of the present invention. As can be seen from the figure, the morphology of ZIF-8 is a rhombic dodecahedron, and ZIF@Fe is also a rhombic dodecahedron but has a corona-like structure on the surface, which is the reason why Fe ions are attached to the surface.

[0136] Figure 2 , Figure 3 The following are respectively ordinary optical photos and scanning electron microscope photos of the hydrogel microneedle dressing provided in Example 1 of the present invention. Figure 2 , Figure 3 It can be seen that the needle tip of the hydrogel microneedle dressing is complete and has a uniform shape.

[0137] 2. Antibacterial properties

[0138] Take two groups of liquid culture medium and add 500 μL 10 6 CFU of E. coli and 500 μL 10 6 CFU of Staphylococcus aureus were added to the hydrogel microneedle dressing prepared in Example 1 and the microneedle prepared in the comparative example, and the two groups of liquid culture media were incubated for 12 hours. Then the absorbance was measured by diluting 100 times, and the plates were coated. After the plates were coated, all solid culture media were placed in a bacterial incubator for 24 hours, taken out, observed, and photographed. Figure 4 .

[0139] The results showed that when the hydrogel microneedle dressing prepared in Example 1 was added, no bacteria grew on the surface of the solid culture medium group, and the absorbance value results were the same; bacteria grew on the surface of the solid culture medium groups in Comparative Examples 1 to 4. This shows that only the hydrogel microneedle dressing prepared in Example 1 has a strong bactericidal effect, and the antibacterial rates of different groups are shown in Table 1. Figure 5 .

[0140] 3. Verification of antibacterial mechanism

[0141] SEM bacterial morphology was used to observe the bacterium to verify the bactericidal mechanism of the nanozyme. Through observation under a fluorescence microscope, it was found that only the hydrogel microneedle dressing solid culture medium group prepared in Example 1 had a large amount of active oxygen species on the surface. Figure 6 ; This indicates that under the action of nanozymes, ZIF-8@Fe induces the production of ROS, resulting in bacterial lysis and death.

[0142] 4. Verification of the cascade mechanism

[0143] The hydrogel microneedle dressing prepared in Example 1 of the present invention and the microneedle dressing prepared in Comparative Examples 1 to 4 and the blank group were inoculated with 10 6 CFU of Staphylococcus aureus in a 24-well plate and incubate for 12 hours. Then dilute 100 times and apply to the plate. After applying the plate, put all solid culture media into a bacterial incubator and culture for 24 hours, then take them out, observe, and take pictures. Figure 7 It was observed that no bacteria grew on the surface of the solid culture medium group of the hydrogel microneedle dressing prepared in Example 1, while other groups had obvious bacterial growth.

[0144] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0145] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A hydrogel microneedle dressing, characterized in that: The hydrogel microneedle dressing comprises a substrate and a hydrogel needle tip located on the substrate; The raw materials of the hydrogel needle tip include, by weight: 20-40 parts of oxidized hyaluronic acid, 20-40 parts of carboxymethyl chitosan, 2-16 parts of iron-loaded ZIF-8 nanoparticles, 1-2 parts of glucose oxidase, and 402-457 parts of water.

2. The hydrogel microneedle dressing according to claim 1, characterized in that: The raw materials of the hydrogel needle tip include, by weight: 25-35 parts of oxidized hyaluronic acid, 25-35 parts of carboxymethyl chitosan, 6-10 parts of iron-loaded ZIF-8 nanoparticles, 1-2 parts of glucose oxidase, and 422-437 parts of water.

3. The hydrogel microneedle dressing according to claim 2, characterized in that: The raw materials of the hydrogel needle tip include, by weight: 30 parts of oxidized hyaluronic acid, 30 parts of carboxymethyl chitosan, 8 parts of iron-loaded ZIF-8 nanoparticles, 2 parts of glucose oxidase, and 430 parts of water.

4. The method for preparing the hydrogel microneedle dressing according to any one of claims 1 to 3, characterized in that: include: Dissolving the formulated amount of iron-loaded ZIF-8 nanoparticles and glucose oxidase in water to obtain a precursor solution; The hydrogel needle tip precursor is obtained by dissolving the formulated amount of carboxymethyl chitosan and oxidized hyaluronic acid with the precursor solution; The hydrogel microneedle dressing is prepared by a microneedle dressing molding process using the hydrogel needle tip precursor and the precursor solution of the substrate.

5. The method for preparing the hydrogel microneedle dressing according to claim 4, characterized in that: The preparation method of the iron-loaded ZIF-8 nanoparticles is: The ZIF-8 nanoparticles, tannic acid and ferric chloride are reacted in the dark to obtain ZIF-8 nanoparticles loaded with iron.

6. The method for preparing the hydrogel microneedle dressing according to claim 5, characterized in that: The mass ratio of the ZIF-8 nanoparticles, tannic acid and ferric chloride is 100-200:4-8:4-8.

7. The method for preparing the hydrogel microneedle dressing according to claim 4, characterized in that: The hydrogel microneedle dressing molding process comprises: The hydrogel needle tip precursor is cast on a PDMS template, centrifuged, and then the precursor solution of the substrate is added, and the mixture is centrifuged again, dried, and demolded to obtain the hydrogel microneedle dressing.

8. The method for preparing the hydrogel microneedle dressing according to claim 7, characterized in that: The precursor solution of the substrate is a hyaluronic acid solution.

9. The method for preparing the hydrogel microneedle dressing according to claim 8, characterized in that: The concentration of the hyaluronic acid solution is 40-80 mg / mL.

10. Use of the hydrogel microneedle dressing according to claim 1 in preparing a medical skin wound dressing.

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