A flexible self-powered conductive hydrogel microneedle dressing as well as a preparation method and application thereof

Abstract

The present application relates to the technical field of biomedical materials and scar treatment, and particularly relates to a flexible self-powered conductive hydrogel microneedle dressing and a preparation method and application thereof, the dressing is an integrated wearable structure, comprising a microneedle layer, a conductive hydrogel layer, an air cell layer and an encapsulation layer, the conductive hydrogel layer serves as an ion conducting layer of a flexible zinc-air cell cathode, and a zinc anode is connected to a conductive network at the edge of the conductive hydrogel through a flexible lead; the conductive hydrogel is prepared by using acrylic acid-2-methoxyethyl ester, etc., and a dry-wet separation activated zinc-air cell is integrated to realize self-power supply; the present application does not need an external power supply, has good portability, can be well attached to the skin, regulates the scar repair process through continuous and accurate electric stimulation, promotes the migration of fibroblasts, regulates collagen synthesis, inhibits inflammation and fibrosis, has excellent biocompatibility, simplifies the operation process, reduces the medical cost, and is suitable for the treatment of hypertrophic scars and keloids.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials and scar treatment technology, specifically a flexible self-powered conductive hydrogel microneedle dressing, its preparation method, and its application. Background Technology

[0002] Scars, especially hypertrophic scars and keloids, not only affect appearance but can also lead to functional impairment and psychological distress. Traditional scar treatments include surgical excision, pressure therapy, silicone dressings, and local steroid injections, but these methods often have limitations such as poor efficacy, high recurrence rates, or side effects. In recent years, electrical stimulation, as a non-invasive treatment, has received widespread attention in the field of skin wound healing and tissue regeneration. Studies have shown that appropriate electrical stimulation can effectively regulate cell behavior, promote fibroblast proliferation and migration, regulate collagen synthesis and remodeling, and inhibit inflammatory responses and fibrosis processes; in addition, electrical stimulation can also promote angiogenesis and nerve regeneration, which is crucial for the healing of complex wounds.

[0003] However, existing electrostimulation devices typically suffer from high complexity, large size, poor portability, and reliance on external power sources. While conductive hydrogels, as an emerging biomaterial, are ideal for wearable bioelectronic devices and therapeutic applications due to their excellent biocompatibility, flexibility, high water content, and tunable electrical properties, serving as carriers for electrostimulation and achieving good skin adhesion; and flexible zinc-air batteries are considered ideal self-powered options due to their high energy density, cost-effectiveness, environmental friendliness, and inherent flexibility, as well as their compatibility with the low voltage required for electrostimulation therapy, an integrated solution is still lacking for electrostimulation therapy of scars.

[0004] Existing electrical stimulation devices are generally bulky and unsuitable for long-term wear, which restricts patients' daily activities and leads to poor compliance. Most devices require a power supply or frequent battery replacements, which increases the cost and inconvenience of use and makes it difficult to achieve continuous and uninterrupted treatment. Traditional electrode materials do not adhere well to the skin, which may cause skin discomfort or allergies, and they are difficult to adhere tightly to irregular scar surfaces, affecting the effect of electrical stimulation.

[0005] Existing technologies typically separate the electrical stimulation device from the dressing, increasing operational complexity and making it difficult to achieve precise and localized treatment. Therefore, in view of the above situation, there is an urgent need to develop a flexible, self-powered, conductive hydrogel microneedle dressing, its preparation method, and its application to overcome the shortcomings in current practical applications. Summary of the Invention

[0006] The purpose of this invention is to provide a flexible, self-powered, conductive hydrogel microneedle dressing, its preparation method, and its application, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A flexible self-powered conductive hydrogel microneedle dressing includes a microneedle layer, a conductive hydrogel layer, an air battery layer and an encapsulation layer stacked sequentially.

[0009] The conductive hydrogel layer serves as the cathode ion conducting layer of the air battery layer. The zinc anode of the air battery layer is connected to the conductive network at the edge of the conductive hydrogel layer via flexible leads. The microneedle layer is electrically connected to the conductive hydrogel layer.

[0010] This allows the current to flow from the zinc anode through the flexible lead, conductive network, conductive hydrogel layer, microneedle layer, and human skin tissue, and then back to the air electrode of the air battery layer, forming a closed electrical stimulation circuit.

[0011] As a further aspect of the present invention: the microneedle layer is integrally formed with the conductive hydrogel layer, and the microneedle layer is composed of an array structure of multiple microneedles;

[0012] The microneedles have a length of 200-500 μm, a base diameter of 100-200 μm, a tip angle of 15-30°, and an array density of 100-400 needles / cm². 2 .

[0013] As a further aspect of the present invention: the conductive hydrogel layer is prepared using 2-methoxyethyl acrylate as the main monomer and imidazole ionic liquid as the crosslinking agent and conductive medium;

[0014] The conductive hydrogel layer has a uniform porous structure.

[0015] As a further aspect of the present invention: the air battery layer is a dry-wet separation activated zinc-air battery, comprising a zinc foil negative electrode, a ruptureable electrolyte sealed bag, and a pure carbon air electrode stacked sequentially.

[0016] After activation, the air battery layer outputs a voltage of 1.2-1.4V and an output current of 10-200μA.

[0017] As a further aspect of the present invention: the encapsulation layer is an ePTFE hydrophobic and breathable membrane, which is sealed to the edge of the conductive hydrogel layer by a hot-pressing process;

[0018] An easy-tear seal is provided on the encapsulation layer at the position corresponding to the electrolyte sealing bag.

[0019] As a further aspect of the present invention: an anti-fibrotic drug is preloaded into the matrix of the conductive hydrogel layer, and the anti-fibrotic drug is loaded into the porous structure of the conductive hydrogel by physical adsorption, thereby achieving synergistic treatment of electrical stimulation and sustained drug release.

[0020] A method for preparing a flexible, self-powered, conductive hydrogel microneedle dressing as described above includes the following steps:

[0021] S1: Prepare a conductive hydrogel precursor solution, inject the precursor solution into a microneedle mold, and demold after photocuring to obtain an integrally formed microneedle layer and conductive hydrogel layer.

[0022] S2: Prepare a dry-wet separation activated zinc-air battery as an air battery layer;

[0023] S3: The air battery layer is bonded to the conductive hydrogel layer, and the conductive network at the edge of the conductive hydrogel layer is connected to the zinc anode by a flexible lead. Then, the layer is sealed and encapsulated to obtain the flexible self-powered conductive hydrogel microneedle dressing.

[0024] As a further aspect of the present invention: in step S1, the conductive hydrogel precursor liquid is prepared by mixing and stirring a main monomer, a crosslinking agent, an ionic liquid and a photoinitiator, and the photocuring is performed by irradiation with an ultraviolet lamp.

[0025] As a further aspect of the present invention: in step S3, the flexible lead is bonded to the conductive network by conductive silver paste and fixed to the surface of the encapsulation layer by medical pressure-sensitive adhesive.

[0026] The application of a flexible, self-powered, conductive hydrogel microneedle dressing as described above in the preparation of scar treatment products, wherein the scars include hypertrophic scars and keloids.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] The flexible self-powered conductive hydrogel microneedle dressing provided by this invention can effectively regulate the scar repair process through continuous and precise electrical stimulation, promote fibroblast proliferation and migration, regulate collagen synthesis and remodeling, and inhibit inflammatory response and fibrosis process, thereby improving the appearance and function of scars.

[0029] Cellular experiments showed that fibroblasts migrated significantly under stimulation with 1V voltage and 10μA current. HE staining and MT staining results showed that the electrostimulated microneedle patch group had the smallest granulation tissue gap width, the fewest inflammatory cells, and significant collagen accumulation in the wound regeneration tissue, confirming its excellent anti-infection and healing-promoting ability.

[0030] The dressing is self-powered and requires no external power source, which improves the portability and convenience of treatment. Patients can receive treatment anytime and anywhere, which improves treatment adherence and quality of life.

[0031] In addition, the dressing of the present invention has excellent biocompatibility and comfort. The conductive hydrogel can fit well with the skin, effectively reducing the discomfort and allergic reactions that may be caused by traditional electrodes, and providing users with a comfortable wearing experience.

[0032] The integrated and wearable design of this invention simplifies the operation process, reduces reliance on professional medical personnel, and lowers medical costs and operational complexity. Attached Figure Description

[0033] Figure 1 This is a three-dimensional structural diagram of the flexible self-powered conductive hydrogel microneedle dressing in an embodiment of the present invention.

[0034] Figure 2 This is a magnified schematic diagram of the microneedle structure in an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of cell migration under a microscope after electrical stimulation in an embodiment of the present invention;

[0036] In A, human epidermal fibroblasts were stimulated with a voltage of 1V and a current of 5μA. Some cells migrated, no electrolysis occurred, and cell proliferation occurred. In B, human epidermal fibroblasts were stimulated with a voltage of 1V and a current of 10μA. Almost all cells migrated, no electrolysis occurred, and cell proliferation occurred.

[0037] Figure 4 This is a schematic diagram of HE staining and MT staining in an embodiment of the present invention.

[0038] In the diagram: 1-microneedle layer, 2-conductive hydrogel layer, 3-air battery layer, 4-microneedle. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0041] Please see Figures 1-4 This invention provides a flexible, self-powered conductive hydrogel microneedle dressing, comprising, from bottom to top, a microneedle layer 1, a conductive hydrogel layer 2, an air battery layer 3, and an encapsulation layer. The conductive hydrogel layer 2 serves as the ion-conducting layer for the cathode of the air battery layer 3, and the zinc anode of the air battery layer 3 is connected to a conductive network at the edge of the conductive hydrogel layer 2 via flexible leads.

[0042] The current flows out from the zinc foil negative electrode, and passes sequentially through the flexible lead wire, the conductive network at the edge of the conductive hydrogel, the conductive hydrogel layer 2, the microneedle layer 1, the scar tissue, the skin surface, the pure carbon air electrode of the air battery layer 3, and the zinc foil negative electrode, forming a closed circuit to achieve continuous and precise electrical stimulation treatment of the scar tissue.

[0043] This dressing requires no external power source, possesses excellent flexibility and biocompatibility, and can adhere well to the skin. Through electrical stimulation, it effectively regulates the scar repair process, promotes fibroblast proliferation and migration, regulates collagen synthesis and remodeling, inhibits inflammatory responses and fibrosis processes, and forms an integrated and wearable treatment system.

[0044] The microneedle layer 1 and the conductive hydrogel layer 2 are integrally formed, and the array structure consists of multiple microneedles 4. The length of the microneedles 4 is 200-500 μm, the bottom diameter is 100-200 μm, the tip angle is 15-30°, and the array density is 100-400 microneedles / cm. 2 The microneedles are arranged in a square pattern. This parameter design ensures that the microneedles 4 can smoothly penetrate the stratum corneum of the skin to reach the dermis (the target tissue for scar treatment), while avoiding excessive puncture and tissue damage. The microneedles 4 and the conductive hydrogel layer 2 have the same conductivity, which can evenly introduce the current conducted by the conductive hydrogel layer 2 into the scar tissue, achieving deep electrical stimulation and improving the treatment effect on hypertrophic scars and keloids.

[0045] The conductive hydrogel layer 2 is the core functional layer of the dressing, combining electrical stimulation conduction, battery ion conduction, and skin adhesion functions. A 5mm wide silver paste conductive strip is printed along the upper edge of the conductive hydrogel layer 2 as a conductive network to connect to the zinc anode of the air battery layer 3. The conductive hydrogel layer 2 is prepared using 2-methoxyethyl acrylate (MEA) as the main monomer, 1-vinyl-3-butylimidazolium tetrafluoroborate (IL1) as the crosslinking agent, and 1-ethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (IL2) as the ionic liquid.

[0046] By adjusting the concentration of the ionic liquid, the conductivity of the conductive hydrogel layer 2 was maintained at 0.5 S / cm at room temperature, effectively conducting electrical stimulation. The conductive hydrogel layer 2 exhibits a tensile strength of 0.2 MPa, an elongation at break of 500%, and a compressive modulus of approximately 50 kPa at 50% strain, demonstrating excellent flexibility and mechanical strength, allowing for good skin adhesion and adaptation to skin deformation. SEM images show that the conductive hydrogel layer 2 possesses a uniform porous structure with pore sizes ranging from 50 to 200 μm. This porous structure facilitates the transport of water and ions, providing a stable ionic environment for electrical stimulation. The conductive hydrogel layer 2 exhibits a water loss rate of less than 15% within 24 hours, demonstrating good water retention capacity and the ability to maintain a moist state for extended periods. Cytotoxicity assays showed a human fibroblast survival rate of over 90%, indicating good biocompatibility.

[0047] The air battery layer 3 is a dry-wet separation activated zinc-air battery, comprising, from bottom to top, a zinc foil negative electrode, a polyacrylamide gel electrolyte sealed capsule, and a pure carbon air electrode; the zinc foil negative electrode is 0.1 mm thick, and the pure carbon air electrode is 0.1 mm thick. During storage, the electrolyte is sealed in the capsule, the battery contains no water, and there is no self-discharge, allowing for long-term storage and effectively extending shelf life. To use, tearing open the seal or pressing down causes the electrolyte capsule to rupture, allowing the electrolyte to flow out and wet the electrode, thus activating the battery and outputting a microcurrent of 10–200 μA. Operation is simple. The battery's operating voltage is approximately 1.2–1.4 V, compatible with the low voltage required for electrical stimulation therapy, reducing the potential risk of tissue damage.

[0048] The encapsulation layer is an ePTFE hydrophobic and breathable membrane with a thickness of 20-50 μm, covering the upper surface and sides of the air battery layer 3. It is sealed to the edge of the conductive hydrogel layer 2 via a hot-pressing process. The hot-pressing temperature is 80-100℃, and the hot-pressing pressure is 0.2-0.5 MPa. The air permeability of the ePTFE hydrophobic and breathable membrane is ≥1000 mL / (cm³). 2 • 24h), with an IPX7 waterproof rating, ensuring oxygen supply to the air electrode of the air battery layer 3 while preventing bodily fluids from penetrating into the battery, ensuring stable operation in a biological environment. An easy-tear aluminum foil seal is provided on the encapsulation layer corresponding to the electrolyte sealing bag for easy battery activation by the user. The flexible leads are made of 0.1mm diameter tin-plated copper wire, wrapped with an external silicone insulating layer, and fixed to the surface of the encapsulation layer with medical pressure-sensitive adhesive.

[0049] The preparation method of the flexible self-powered conductive hydrogel microneedle dressing of the present invention includes the following steps:

[0050] S1: Preparation of conductive hydrogel and microneedle layer 1

[0051] MEA and IL1 were weighed in a molar ratio of 1:5, and then IL2, which accounted for 30% of the total mass of MEA and IL1, was added. The mixture was stirred thoroughly with a magnetic stirrer for 2 hours. Subsequently, 1% of the photoinitiator 1-hydroxycyclohexylphenyl ketone, which accounted for 1% of the total mass of MEA and IL1, was added, and the mixture was stirred thoroughly with a magnetic stirrer for another 2 hours to obtain the hydrogel precursor solution. The hydrogel precursor solution was injected into a microneedle mold made of polydimethylsiloxane (PDMS) and cured by irradiation with a 20W ultraviolet lamp for 100 seconds. After demolding, an integrally formed microneedle layer 1 and conductive hydrogel layer 2 were obtained.

[0052] Taking a specific gel formulation as an example: Weigh 0.01 mol (1.3 g) of MEA, 0.002 mol (0.476 g) of IL1, and 0.5328 g of IL2, stir thoroughly, add 0.017 g of photoinitiator 1-hydroxycyclohexylphenyl ketone, stir thoroughly again, inject into a microneedle mold, and irradiate with a 20W ultraviolet lamp for 100 seconds to obtain hydrogel and microneedle layer 1.

[0053] S2: Fabrication of air battery layer 3

[0054] A 0.1 mm thick zinc foil was cut as the negative electrode, and a 0.1 mm thick pure carbon paper was cut as the air electrode. A polyacrylamide gel electrolyte was prepared and sealed in a ruptureable polyethylene bag. The zinc foil negative electrode, the electrolyte sealed bag, and the pure carbon air electrode were stacked in that order to obtain the air battery layer 3 semi-finished product.

[0055] S3: Integrated Package

[0056] One side of the pure carbon air electrode of the air battery layer 3 is attached to the upper surface of the conductive hydrogel layer 2; one end of the flexible lead is bonded to the silver paste conductive network at the edge of the conductive hydrogel layer 2 with conductive silver paste, and the other end is connected to the zinc foil negative electrode of the air battery layer 3; an ePTFE hydrophobic and breathable membrane is covered on the upper surface and side of the air battery layer 3, and the edges are hot-pressed and sealed at a temperature of 90°C and a pressure of 0.3 MPa; an easy-tear aluminum foil seal is pasted on the encapsulation layer at the position corresponding to the electrolyte sealing bag to obtain the final flexible self-powered conductive hydrogel microneedle dressing.

[0057] When using the dressing, align the microneedle layer 1 with the scar area and press the dressing vertically to allow the microneedles 4 to penetrate the stratum corneum and reach the dermis. Remove the easy-tear aluminum foil seal on the encapsulation layer and press the area of ​​the air battery layer 3 to rupture the electrolyte sealing bag and activate the battery. After the battery is activated, it outputs a microcurrent of 10-200μA, which is conducted to the scar tissue through the conductive hydrogel layer 2 and the microneedle layer 1 to achieve continuous electrical stimulation treatment. Each application time is 72 hours, after which a new dressing should be replaced.

[0058] Example 1: Basic Flexible Self-Powered Conductive Hydrogel Microneedle Dressing

[0059] The dressing structure of this embodiment is as described in the overall technical solution above, including a microneedle layer 1, a conductive hydrogel layer 2, an air battery layer 3, and an encapsulation layer. The microneedles 4 have a length of 300 μm, a bottom diameter of 150 μm, a tip angle of 20°, and an array density of 200 needles / cm². 2 The conductivity of the conductive hydrogel layer 2 is 0.5 S / cm; after activation, the air battery layer 3 has an output voltage of 1.3V, an output current of 50μA, and a continuous power supply time of 72 hours.

[0060] The dressing in this embodiment can achieve self-powered continuous electrical stimulation without the need for an external power source, making it highly portable. Under stimulation with 1V and 10μA, significant migration of human fibroblasts was observed in cell experiments. HE and MT staining results showed that, compared with the control group and the simple electrical stimulation group, the electrical stimulation microneedle patch group of this embodiment had the smallest granulation tissue gap width, the fewest inflammatory cells, and significant collagen accumulation in the wound regeneration tissue, confirming its excellent anti-infection and healing-promoting abilities, and its ability to effectively regulate the scar repair process.

[0061] Example 2: Self-powered electrostimulation hydrogel dressing with drug sustained-release function

[0062] Based on Example 1, this embodiment preloads an appropriate amount of the anti-fibrotic drug triamcinolone acetonide into the matrix of the conductive hydrogel layer 2 via physical adsorption. This dressing achieves a synergistic effect of electrical stimulation and sustained drug release. Electrical stimulation can promote local blood circulation and cell permeability, which is beneficial to drug absorption and action, further enhancing the scar treatment effect.

[0063] Example 3: Self-powered dressing based on chitosan / carbon nanotube composite conductive hydrogel

[0064] The difference between this embodiment and Embodiment 1 is that the conductive hydrogel layer 2 is prepared by chemical cross-linking using biodegradable chitosan as a matrix, and multi-walled carbon nanotubes (MWCNTs) are uniformly dispersed to provide conductivity. Chitosan has good biocompatibility, antibacterial properties, and healing-promoting characteristics. This dressing can reduce the risk of infection at the scar site while providing stable electrical stimulation, further improving the safety and efficacy of treatment.

[0065] Example 4: Temperature-sensitive self-powered conductive hydrogel dressing

[0066] Based on Example 1, this embodiment introduces a thermosensitive monomer, N-isopropylacrylamide (NIPAM), copolymerized with MEA during the preparation of the conductive hydrogel layer 2. This dressing can adjust its physical properties according to changes in skin surface temperature. When applied to scar tissue with an inflammatory response (elevated local skin temperature), the hydrogel microstructure undergoes slight contraction, thereby squeezing the internal ionic liquid, increasing the local charge density, and achieving the effect of intelligently regulating the intensity of electrical stimulation. Simultaneously, the thermosensitive properties enhance the dressing's adhesion stability in different environments, further improving patient comfort.

[0067] Example 5: Multilayer gradient conductivity deep electrical stimulation dressing

[0068] This embodiment, based on Embodiment 1, adjusts the addition ratio of IL2 in different layers of hydrogel, establishing a mass gradient of 30%-20%-10% from the tip of microneedle 4 to the basal layer of conductive hydrogel layer 2, thus constructing a conductive network with gradient conductivity. This design guides current more effectively through microneedle 4 into the dermis, rather than merely conducting it on the skin surface. Experiments show that the gradient conductivity design can increase the current density in deep scar tissue by 20%-30%, exhibiting a more significant therapeutic effect on thicker hypertrophic scars or deep keloids, achieving precise deep-targeted electrical stimulation.

[0069] Example 6: Self-powered electrical stimulation dressing with visual monitoring function

[0070] This embodiment, based on Embodiment 1, integrates a pH-sensitive color-changing indicator, bromothymol blue, into the conductive hydrogel layer 2. During scar repair, the tissue's pH value changes as the inflammatory response subsides. This dressing, while providing electrical stimulation therapy, can visually reflect the healing status of the scar site through color changes. This provides patients and doctors with a non-invasive monitoring method, allowing them to determine treatment progress without removing the dressing, enhancing the product's interactivity and clinical applicability.

[0071] In summary, this invention provides an integrated, wearable scar electrostimulation treatment system by integrating conductive hydrogel microneedles with a flexible zinc-air battery. This solves the problems of existing electrostimulation devices being complex, bulky, poorly portable, and dependent on external power sources. This dressing requires no external power source, greatly improving the portability and convenience of treatment, allowing patients to receive treatment anytime, anywhere, thus improving treatment adherence and quality of life.

[0072] Conductive hydrogels possess excellent biocompatibility and flexibility, allowing for excellent skin adhesion and effectively reducing discomfort and allergic reactions that may occur with traditional electrodes, providing users with a comfortable wearing experience. The microneedle structure enables deep electrical stimulation, precisely targeting scar tissue and significantly improving treatment outcomes. The integrated design simplifies the procedure, reduces reliance on professional medical personnel, and is expected to lower the cost of long-term treatment.

[0073] It should be noted that, in this invention, although the specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flexible, self-powered, conductive hydrogel microneedle dressing, characterized in that, It includes a microneedle layer (1), a conductive hydrogel layer (2), an air battery layer (3), and an encapsulation layer stacked in sequence; The conductive hydrogel layer (2) serves as the cathode ion conduction layer of the air battery layer (3). The zinc anode of the air battery layer (3) is connected to the conductive network at the edge of the conductive hydrogel layer (2) via a flexible lead. The microneedle layer (1) is electrically connected to the conductive hydrogel layer (2). The current flows from the zinc anode through the flexible lead, conductive network, conductive hydrogel layer (2), microneedle layer (1) and human skin tissue, and then flows back to the air electrode of the air battery layer (3), forming a closed electrical stimulation circuit.

2. The flexible self-powered conductive hydrogel microneedle dressing according to claim 1, characterized in that, The microneedle layer (1) is integrally formed with the conductive hydrogel layer (2), and the microneedle layer (1) is composed of an array structure of multiple microneedles (4); The microneedles (4) have a length of 200-500 μm, a bottom diameter of 100-200 μm, a tip angle of 15-30°, and an array density of 100-400 needles / cm. 2 .

3. The flexible self-powered conductive hydrogel microneedle dressing according to claim 1, characterized in that, The conductive hydrogel layer (2) is prepared with 2-methoxyethyl acrylate as the main monomer and imidazole ionic liquid as the crosslinking agent and conductive medium. The conductive hydrogel layer (2) has a uniform porous structure.

4. The flexible self-powered conductive hydrogel microneedle dressing according to claim 1, characterized in that, The air battery layer (3) is a dry-wet separation activated zinc-air battery, which includes a zinc foil negative electrode, a ruptureable electrolyte sealed bag and a pure carbon air electrode stacked in sequence. The air battery layer (3) has an output voltage of 1.2-1.4V and an output current of 10-200μA after activation.

5. The flexible self-powered conductive hydrogel microneedle dressing according to claim 1, characterized in that, The encapsulation layer is an ePTFE hydrophobic and breathable membrane, which is sealed to the edge of the conductive hydrogel layer (2) by a hot pressing process; An easy-tear seal is provided on the encapsulation layer at the position corresponding to the electrolyte sealing bag.

6. The flexible self-powered conductive hydrogel microneedle dressing according to claim 1, characterized in that, The conductive hydrogel layer (2) is preloaded with an anti-fibrotic drug in its matrix. The anti-fibrotic drug is loaded into the porous structure of the conductive hydrogel by physical adsorption, thereby achieving synergistic treatment of electrical stimulation and sustained drug release.

7. A method for preparing a flexible self-powered conductive hydrogel microneedle dressing as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Prepare conductive hydrogel precursor liquid, inject the precursor liquid into microneedle mold, and demold after photocuring to obtain an integrally formed microneedle layer (1) and conductive hydrogel layer (2). S2: Prepare a dry-wet separation activated zinc-air battery as an air battery layer (3); S3: The air battery layer (3) is bonded to the conductive hydrogel layer (2), and the conductive network at the edge of the zinc anode and the conductive hydrogel layer (2) is connected by a flexible lead wire. Then, the flexible self-powered conductive hydrogel microneedle dressing is sealed by an encapsulation layer.

8. The method for preparing the flexible self-powered conductive hydrogel microneedle dressing according to claim 7, characterized in that, In step S1, the conductive hydrogel precursor liquid is prepared by mixing and stirring a main monomer, a crosslinking agent, an ionic liquid and a photoinitiator, and the photocuring is performed by irradiation with an ultraviolet lamp.

9. The method for preparing the flexible self-powered conductive hydrogel microneedle dressing according to claim 7, characterized in that, In step S3, the flexible lead is bonded to the conductive network with conductive silver paste and fixed to the surface of the encapsulation layer with medical pressure-sensitive adhesive.

10. The use of a flexible, self-powered, conductive hydrogel microneedle dressing as described in any one of claims 1-6 in the preparation of scar treatment products, wherein the scar includes hypertrophic scars and keloids.

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