Microneedle patch for wound repair and preparation method thereof

Abstract

The invention relates to the technical field of microneedle preparation, and discloses a microneedle patch for wound repair and a preparation method thereof. The microneedle patch includes: a microneedle substrate; the microneedle is arranged on the surface of the microneedle substrate; the microneedle comprises a cross-linked body and polydopamine nanoparticles which are coated by the cross-linked body and are modified by lysine, the cross-linked body is obtained by cross-linking sodium alginate grafted with 3-aminophenylboronic acid and methacrylated hyaluronic acid. The microneedle patch for wound healing provided by the invention has a glucose response function, can automatically adjust the release amount according to the wound environment, and realizes long-acting and accurate wound nursing. And the microneedle patch also has antibacterial and antioxidant effects.

Description

Technical Field

[0001] The present invention relates to the technical field of microneedle preparation, and in particular to a microneedle patch for wound repair and a preparation method thereof. Background Art

[0002] In recent years, microneedles have been gradually applied to the field of wound care, and have received widespread attention for its advantages of efficient drug delivery, low invasiveness and simple operation. The existing microneedle dressings mainly include two categories: polymer microneedles and metal microneedles: Among them, polymer microneedles: This type of microneedle is usually made of biodegradable polymers (such as hyaluronic acid, alginate, etc.), and gradually releases active substances after penetrating the skin, which promotes healing. Polymer microneedles are considered to be one of the ideal wound care materials due to their good biocompatibility and flexibility. Metal microneedles: Metal microneedles are usually made of metals such as stainless steel and titanium, and have high mechanical strength, which is suitable for drug delivery in thicker skin areas. However, since metal materials are not easy to degrade and may cause bioincompatibility problems, the application of metal microneedles in wound care is subject to certain restrictions.

[0003] In addition, in the existing microneedle technology, the release of active ingredients in the microneedles is not controlled: most polymer microneedles release drugs during the degradation process, but the release rate is difficult to accurately control, resulting in concentrated release of active ingredients in the early stage and weakened effects in the later stage, making it difficult to achieve long-term care. Lack of multifunctionality: Most existing microneedle patches have only single or limited functions, usually only providing antibacterial or antioxidant effects, and cannot meet multiple care needs at the same time. The healing process of the wound requires the regulation of multiple factors, including antibacterial, antioxidant, and promotion of cell proliferation, which are difficult to take into account with existing microneedles.

[0004] Therefore, the prior art needs to be further improved and enhanced. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a microneedle patch for wound healing and a preparation method thereof, aiming to solve the technical problems that the existing microneedle patches for wound healing have single functions and uncontrolled release of active ingredients.

[0006] The above object of the present invention is achieved through the following technical solution: a microneedle patch for wound repair, comprising:

[0007] Microneedle base;

[0008] A microneedle, wherein the microneedle is arranged on the surface of the microneedle substrate; the microneedle comprises a crosslinker and lysine-modified polydopamine nanoparticles coated by the crosslinker;

[0009] The cross-linked body is obtained by cross-linking sodium alginate grafted with 3-aminophenylboronic acid and methacryloyl hyaluronic acid.

[0010] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0011] As a preferred technical solution, the microneedle patch for wound repair, wherein the microneedles further include a functional layer coated on the surface of the microneedles; the functional layer is selected from one or more of an antibacterial layer containing antibacterial ingredients, an antioxidant layer containing antioxidant ingredients, and a growth factor layer that promotes cell proliferation.

[0012] As a preferred technical solution, the microneedle patch for wound repair, wherein the microneedle substrate is obtained by cross-linking methacryloyl hyaluronic acid and methacryloyl gelatin.

[0013] As a preferred technical solution, the microneedle patch for wound repair, wherein the microneedles further comprise: silver nanoparticles, selenium nanoparticles, zinc oxide nanoparticles or magnetic nanoparticles.

[0014] As a preferred technical solution, the microneedle patch for wound repair, wherein the microneedle substrate also contains an auxiliary agent, and the auxiliary agent includes nanocellulose and graphene oxide.

[0015] As a preferred technical solution, the microneedle patch for wound repair, wherein the microneedles also contain electrically responsive conductive polymer gel or conductive polymer; the conductive polymer gel is cross-linked with the cross-linker.

[0016] In a second aspect, a method for preparing a microneedle patch for wound repair comprises:

[0017] Methacrylylated hyaluronic acid is mixed with sodium alginate grafted with 3-aminophenylboronic acid, a photocrosslinker, and polydopamine nanoparticles modified with lysine to obtain a microneedle hybrid gel precursor;

[0018] Injecting the microneedle mixed gel precursor into a microneedle mold, removing bubbles at the needle tip position, and removing the microneedle mixed gel precursor at the non-needle tip portion to obtain a concentrated needle tip material;

[0019] The microneedle base material is injected into the non-needle tip portion of the microneedle mold, and after ultraviolet light curing treatment and demoulding treatment, the microneedle patch is obtained.

[0020] As a preferred technical solution, in the method for preparing a microneedle patch for wound repair, the content of the lysine-modified polydopamine nanoparticles in the microneedle mixed gel precursor is 0.05-0.2 mg / ml.

[0021] As a preferred technical solution, in the method for preparing a microneedle patch for wound repair, the content of the sodium alginate grafted with 3-aminophenylboronic acid in the microneedle mixed gel precursor is 0.1-0.3 g / ml.

[0022] As a preferred technical solution, the method for preparing a microneedle patch for wound repair is described, wherein the microneedle base material is a mixture of methacrylated hyaluronic acid, methacrylated gelatin and a photocrosslinker; the content of methacrylated gelatin in the mixture is 0.4-0.6 g / ml.

[0023] Beneficial effects: Compared with the prior art, the microneedle patch for wound healing provided by the present invention has a glucose response function, can automatically adjust the release amount according to the wound environment, and achieve long-term and accurate wound care. The microneedle patch also has antibacterial and antioxidant effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a microneedle patch for wound repair provided by the present invention;

[0025] Figure 2 It is the swelling rate of microneedles in a microneedle patch for wound repair provided by the present invention in glucose solutions of different concentrations;

[0026] Figure 3 The present invention discloses an antibacterial effect of microneedles in a microneedle patch for wound repair on Staphylococcus aureus and Escherichia coli. DETAILED DESCRIPTION

[0027] The present invention provides a microneedle patch for wound repair and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and do not mean a necessary sequence, unless otherwise specified that a certain sequence must be followed. The serial numbers themselves, such as "first", "second", etc., assigned to the components herein are only used to distinguish the objects described and do not have any order or technical meaning.

[0029] The present invention provides a microneedle patch for wound repair, comprising: a microneedle substrate 10 and microneedles 20 arranged on the surface thereof, wherein the microneedles 20 comprise polydopamine nanoparticles 21 modified with lysine and a crosslinker 22 for encapsulating the polydopamine (PDA-Lys) nanoparticles 21 modified with lysine, wherein the crosslinker 22 is obtained by crosslinking sodium alginate (Alg-PBA) grafted with 3-aminophenylboronic acid and methacryloyl hyaluronic acid (HAMA).

[0030] In this embodiment, Alg-PBA can achieve targeted controlled release through the property of its phenylboronic acid group binding to sugar molecules, and also has antibacterial and antioxidant properties. The addition of PDA-Lys nanoparticles gives the microneedle dressing a significant antioxidant capacity, promotes angiogenesis, and prevents endothelial cells from excessively secreting growth factors such as VEGF due to oxidative stress, thereby avoiding the hardening and degeneration of wound microvessels. At the same time, the continuous release of PDA-Lys nanoparticles in a high-sugar environment helps to remove high levels of free radicals in diabetic wounds.

[0031] The specific release process is as follows:

[0032] 1. Glucose sensitivity based on phenylboronic acid: The phenylboronic acid group in Alg-PBA has a specific reversible binding property with glucose molecules. Under normal circumstances, the phenylboronic acid group forms a stable structure with other molecules in Alg (alginate), so that the active substances in the microneedle (such as PDA-Lys) are blocked in the needle tip material.

[0033] 2. High glucose concentration triggers release: When the microneedle dressing is applied to the wound surface, especially the wound surface with infection or metabolic abnormality, the local glucose concentration will increase significantly. The phenylboronic acid group will specifically bind to the glucose molecule, making the structure of Alg-PBA loose, thereby triggering the gradual release of PDA-Lys encapsulated therein.

[0034] 3. Adaptive regulation of release amount: As the glucose concentration changes, the binding strength of phenylboronic acid and glucose also changes, thus affecting the release rate and dosage of PDA-Lys. At high glucose concentrations, more phenylboronic acid groups will bind to glucose, making the material structure looser and accelerating the release; when the glucose concentration decreases, the structure tends to be stable and the release rate slows down. This adaptive regulation mechanism can achieve on-demand release of drugs, making it have a stabilizing effect at different stages of healing.

[0035] 4. Sustained antibacterial and antioxidant effects: After the release of PDA-Lys, it provides antibacterial and antioxidant effects to remove potential sources of infection and reactive oxygen species (ROS) in the wound, thereby reducing inflammatory responses, promoting cell proliferation, and accelerating the healing process.

[0036] The glucose-responsive release mechanism can automatically adjust the release amount according to the wound environment to achieve long-term, precise wound care. This intelligent response design significantly improves the therapeutic efficiency and safety of microneedle dressings, making it an ideal choice for wound care.

[0037] In one implementation of the present invention, the microneedle substrate can be obtained by cross-linking methacryloyl hyaluronic acid (HAMA) and methacryloyl gelatin (GelMA). Among them, HAMA has high biocompatibility and hydrophilicity, can form a hydrogel structure in the wound environment, effectively maintain a moist environment, and help promote tissue regeneration and wound healing. GelMA has high biocompatibility, helps cell adhesion and proliferation, and has a certain mechanical strength to ensure that the microneedle is stable and reliable during application. GelMA-HAMA as a microneedle substrate provides soft and elastic support, which can better fit the wound and maintain the shape of the microneedle. It should be noted that the microneedle substrate can also be prepared from other soft and breathable materials, such as biocompatible polymers such as polyamino acids (PAA), polyglucosamine (PGA), etc., or directly use medical tape as a microneedle substrate.

[0038] In one implementation of the present invention, a functional layer is also provided on the surface of the microneedle, and the functional layer is selected from one or more of an antibacterial layer containing antibacterial ingredients, an antioxidant layer containing antioxidant ingredients, and a growth factor layer that promotes cell proliferation. For example, the outer layer contains antibacterial ingredients, the middle layer contains antioxidant ingredients, and the innermost layer is a growth factor that promotes cell proliferation. The multi-layer design realizes phased and on-demand release, further improving the management of the entire wound healing process.

[0039] In one implementation of the present invention, the microneedle contains, in addition to the PDA-Lys nanoparticles, silver nanoparticles, selenium nanoparticles, zinc oxide nanoparticles or magnetic nanoparticles (nanoparticles with superparamagnetism or ferromagnetism, such as iron oxide (Fe 3O 4 ) or nickel (Ni) nanoparticles). Work together with PDA-Lys to enhance the antibacterial, anti-inflammatory and antioxidant functions. Increase the types of active ingredients in the microneedles to give them broad-spectrum antibacterial and anti-inflammatory effects, and better adapt to the needs of different types of wounds. Control the release rate or positioning of the drug through an external magnetic field. This design is suitable for scenarios where the drug release rate or positioning needs to be precisely controlled. The drug release can be adjusted according to treatment needs, improving the intelligence level of the microneedle patch.

[0040] In one implementation of the present invention, in addition to PDA-Lys nanoparticles, the microneedle also contains an electrically responsive conductive polymer gel or conductive polymer; the conductive polymer gel is cross-linked with the cross-linked body. Such as polyacrylamide (PAM)-based hydrogels or polyvinylpyrrolidone (PVP) composite materials, these hydrogels will swell or shrink under the action of an electric field. Conductive polymer materials are selected, such as polypyrrole, polyaniline, etc. These materials can produce volume changes under the action of an external electric field or microcurrent to regulate the release of drugs. Local discharge response components are introduced into the microneedle substrate or microneedle material, so that it can accelerate the release of active substances under low voltage stimulation. For specific chronic wounds (such as diabetic foot), low-frequency electrical stimulation can be combined to accelerate local blood circulation and enhance the drug release effect, thereby promoting healing.

[0041] In one implementation of the present invention, a thermosensitive polymer is compounded with an existing material so that the microneedle releases the drug when the temperature rises (such as a local temperature rise caused by inflammation). This temperature-responsive layer can be located on the surface of the needle tip. When the wound surface becomes inflamed and causes a local temperature rise, the temperature-responsive property will trigger the release of the drug, assist in controlling infection and inflammation, and provide a more intelligent nursing effect. For example, when PNIPAAm is compounded with hyaluronic acid, PNIPAAm swells rapidly when the temperature rises, driving the degradable polymer to accelerate degradation.

[0042] In one implementation of the present invention, the microneedle also contains GOx (glucose oxidase) and pH-sensitive materials (such as chitosan, polylactic acid-glycolic acid copolymer, etc.). That is, GOx and pH-sensitive materials are introduced into the cross-linked body, and GOx is used to oxidize glucose into gluconic acid, resulting in a decrease in the pH value of the microenvironment, which promotes the degradation of acid-sensitive materials, thereby achieving drug release. To enhance the adaptability of microneedles during the inflammation period of wounds. In an acidic environment (usually an infection or inflammatory environment), the material structure becomes looser, promoting the rapid release of active ingredients. A more flexible drug release mechanism is achieved through pH response, which can accelerate the release of antibacterial components when the wound inflammation is severe, thereby improving the anti-infection effect.

[0043] In one implementation of the present invention, hemostatic components, such as chitosan or calcium ions, are integrated into the microneedles to promote platelet aggregation and coagulation. In wound care, especially acute wounds or bleeding wounds, the needle tip material can release hemostatic components to achieve rapid hemostasis and provide a good foundation for subsequent healing. Combining hemostasis and healing functions, microneedles are suitable for acute trauma scenarios, such as burns, cuts, etc.

[0044] In one implementation of the present invention, photosensitive materials are combined in microneedles to trigger the release of active ingredients under specific light sources, thereby improving the healing effect. Near-infrared light or low-intensity lasers can be used to non-invasively illuminate the wound, triggering the microneedles to release antibacterial or anti-inflammatory ingredients to promote tissue repair. Light-controlled release can more effectively release drugs in deep wounds or at specific healing stages, achieving more precise wound care.

[0045] In one implementation of the present invention, the microneedles are designed to be slowly degradable, and each layer contains active substances that are gradually released to support continuous treatment for several weeks. It is suitable for patients who are inconvenient to change dressings frequently, such as those who are bedridden for a long time (chronic ulcers or diabetic foot), reducing the nursing workload and improving the healing experience.

[0046] In one implementation of the present invention, nanoparticles with different functions (such as antibacterial, anti-inflammatory, and healing-promoting) are introduced into microneedles to give them composite functions. Silver nanoparticles, selenium nanoparticles, zinc oxide nanoparticles, iron oxide nanoparticles, etc. can be introduced to achieve multiple effects such as antibacterial, accelerated cell repair, and reduced inflammation. The composite nanoparticle design achieves the effect of "one needle for multiple uses", while reducing the amount of materials used and increasing multiple active effects.

[0047] In one implementation of the present invention, the microneedle substrate also contains additives, such as nanocellulose, graphene oxide, etc., which can improve its mechanical strength and elasticity, making it more suitable for application to various skin types and depths. The enhanced substrate material is suitable for thicker skin areas, which can further improve the penetration and support of the microneedles, ensuring that the microneedle patch has a good effect on the skin of different patients.

[0048] In one implementation of the present invention, a layer of dressing layer is further provided on the surface of the microneedle substrate facing the microneedle, and the dressing layer has water-locking and antibacterial functions, and is used to further protect the wound and prevent external infection. The material of the dressing layer is a biocompatible polymer material, such as polyamino acid (PAA), polyglucosamine (PGA), etc.

[0049] Based on the same inventive concept, the present invention also provides a method for preparing a microneedle patch for wound repair, comprising the following steps:

[0050] S10, mixing methacrylylated hyaluronic acid with sodium alginate grafted with 3-aminophenylboronic acid, a photocrosslinker, and polydopamine nanoparticles modified with lysine to obtain a microneedle hybrid gel precursor.

[0051] Specifically, the synthesis of methacryloyl hyaluronic acid includes: using 200 ml of deionized water, adding 2 g of sodium hyaluronate to dissolve; adding 25 ml of methacrylic anhydride dropwise at room temperature; adding 150 ml of 2 mol / L NaOH solution, and adjusting the reaction liquid environment to pH = 8-10; after reacting overnight, filtering and removing the precipitate; 7kDA dialyzed for one week and freeze-dried for 3 days to obtain methacryloyl hyaluronic acid (HAMA).

[0052] The synthesis of sodium alginate grafted with 3-aminophenylboronic acid includes: dissolving 2g Alg in 200ml MES hydrate with a concentration of 0.1M; adding 1.4g EDC and stirring for activation for 15min; adding 0.85g NHS and stirring for activation for 15min; in order to increase the dispersibility and reactivity of the insoluble 3-aminophenylboronic acid, adding 10mL anhydrous ethanol dissolved with 1g of 3-aminophenylboronic acid and stirring overnight; dialyzing (7kDA) for one week and then freeze-drying to obtain sodium alginate grafted with 3-aminophenylboronic acid.

[0053] Preparation of chemically and physically cross-linked glucose and temperature-responsive P(NIPAM-co-AAPBA) hydrogels: 8 mL of deionized water was passed through N 2 Half an hour, then add the monomer NIPAM and the crosslinking agent (BIS or Clay), stir for 30 minutes to make the solution clear, then add 12μL TEMED and different weight monomers 3-acrylamidophenylboronic acid (AAPBA), and finally add water-soluble potassium persulfate (KPS), stir in ice water for 2 minutes, then quickly suck into a 1mL syringe and put it into a 25℃ constant temperature and humidity box for free radical polymerization. After reacting for 24 hours, chemically crosslinked BIS and physically crosslinked Clay gels are obtained. Cut the prepared gel into 2cm thick slices and soak them in water for 48 hours. Change the water regularly to remove unreacted monomers and residual reagents, dry at room temperature, vacuum dry to constant weight, and set aside.

[0054] The synthesis of polydopamine nanoparticles (PDA) includes: mixing dopamine hydrochloride (0.3 mg / ml) with Tris-HCl (pH 8.5, 25 mM) and ethanol (v:v = 4:1) and stirring for 12 hours, and the synthesized polydopamine nanoparticles are centrifuged at 10000 rpm for 5 minutes and then washed three times with ultrapure water.

[0055] The synthesis of PDA-Lys includes: mixing the above-synthesized PDA nanoparticles (1 mg / ml) with lysine (Lys, 0.1 mg / ml) and stirring for 1 hour. Lys can be modified on the surface of the PDA particles through Michael addition and Schiff base reaction.

[0056] S20, injecting the microneedle mixed gel precursor into a microneedle mold, removing bubbles at the needle tip position, and removing the microneedle mixed gel precursor at the non-needle tip portion to obtain a concentrated needle tip material.

[0057] Specifically, a needle tip material hydrogel (microneedle mixed gel precursor, 2% HAMA + 1% Alg-PBA + 0.5% photocrosslinker dissolved in ultrapure water, stirred overnight) containing PDA-Lys nanoparticles (0.1 mg / ml) was added to the microneedle mold, and vacuumed twice at room temperature in a vacuum drying oven to remove bubbles at the needle tip. The hydrogel in the non-needle tip part was sucked out and dried at 4°C for 12 hours. The operation was repeated twice to obtain a concentrated needle tip material.

[0058] S30, injecting the microneedle base material into the non-needle tip portion of the microneedle mold, subjecting the microneedle mold to ultraviolet light curing treatment, and subjecting the microneedle mold to demoulding treatment to obtain the microneedle patch.

[0059] Specifically, the preparation of the microneedle base material includes: 1% HAMA + 5% GelMA + 0.5% photocrosslinker is dissolved in ultrapure water and stirred overnight; the microneedle base material (GelMA-HAMA) is filled into the dressing base layer, and the microneedle dressing is cured in a 365nm UV curing box for 2 minutes, and then the microneedle dressing is removed from the mold with tweezers, placed with the needle tip facing upward, and cured for another 1 minute to obtain a microneedle patch.

[0060] The prepared needle tip material hydrogel was placed in glucose solutions of different concentrations, and its swelling rate was as follows Figure 2 As shown by Figure 2 It can be seen that as the concentration of glucose solution increases, its swelling rate also increases, indicating that the microneedle patch thus formed can achieve triggered release in a high concentration glucose environment. The prepared needle tip material hydrogel was applied to Staphylococcus aureus and Escherichia coli, and the antibacterial effect was as follows Figure 3 As shown. Figure 3 It can be seen that it has a good antibacterial effect on Staphylococcus aureus and Escherichia coli.

[0061] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A microneedle patch for wound repair, characterized in that: include: Microneedle base; A microneedle, wherein the microneedle is disposed on the surface of the microneedle substrate; The microneedle comprises a cross-linked body and lysine-modified polydopamine nanoparticles coated by the cross-linked body; The cross-linked body is obtained by cross-linking sodium alginate grafted with 3-aminophenylboronic acid and methacryloyl hyaluronic acid.

2. The microneedle patch for wound repair according to claim 1, characterized in that: The microneedle further comprises a functional layer coated on the surface of the microneedle; the functional layer is selected from one or more of an antibacterial layer containing antibacterial ingredients, an antioxidant layer containing antioxidant ingredients, and a growth factor layer that promotes cell proliferation.

3. The microneedle patch for wound repair according to claim 1, characterized in that: The microneedle substrate is obtained by cross-linking methacryloyl hyaluronic acid and methacryloyl gelatin.

4. The microneedle patch for wound repair according to claim 1, characterized in that: The microneedle further comprises: silver nanoparticles, zinc oxide nanoparticles or magnetic nanoparticles.

5. The microneedle patch for wound repair according to claim 3, characterized in that: The microneedle substrate also contains auxiliary agents, which include nanocellulose and graphene oxide.

6. The microneedle patch for wound repair according to claim 1, characterized in that: The microneedle also contains electrically responsive conductive polymer gel or conductive polymer; the conductive polymer gel is cross-linked with the cross-linking body.

7. A method for preparing a microneedle patch for wound repair, characterized in that: include: Methacrylylated hyaluronic acid is mixed with sodium alginate grafted with 3-aminophenylboronic acid, a photocrosslinker, and polydopamine nanoparticles modified with lysine to obtain a microneedle hybrid gel precursor; Injecting the microneedle mixed gel precursor into a microneedle mold, removing bubbles at the needle tip position, and removing the microneedle mixed gel precursor at the non-needle tip portion to obtain a concentrated needle tip material; The microneedle base material is injected into the non-needle tip portion of the microneedle mold, and after ultraviolet light curing treatment and demoulding treatment, the microneedle patch is obtained.

8. The method for preparing a microneedle patch for wound repair according to claim 7, characterized in that: The content of the lysine-modified polydopamine nanoparticles in the microneedle mixed gel precursor is 0.05-0.2 mg / ml.

9. The method for preparing a microneedle patch for wound repair according to claim 7, characterized in that: The content of the sodium alginate grafted with 3-aminophenylboronic acid in the microneedle mixed gel precursor is 0.1-0.3 g / ml.

10. The method for preparing a microneedle patch for wound repair according to claim 7, characterized in that: The microneedle substrate material is a mixture of methacrylated hyaluronic acid, methacrylated gelatin and a photocrosslinking agent; the content of methacrylated gelatin in the mixture is 0.4-0.6 g / ml.

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