A self-energized gelatin-based hydrogel patch and its preparation method

Abstract

This invention relates to the field of hydrogel patch technology, specifically to a self-energized gelatin-based hydrogel patch and its preparation method. The patch comprises, from top to bottom, an upper encapsulation layer, a two-dimensional gelatin-based hydrogel functional layer, a conductive electrode layer, and a lower encapsulation layer. The functional layer uses gelatin as the hydrogel matrix and contains two-dimensional materials, plasticizers, and crosslinking agents. The two-dimensional materials and gelatin combine to form a three-dimensional network structure. The patch integrates self-energized electrical stimulation, photothermal therapy, and flexible sensing functions. It generates electricity through human movement without an external power source, achieving electrothermal synergy to promote wound healing. This patch achieves electrothermal synergy to promote wound healing without an external power source, also possesses physiological sensing functions, good biocompatibility, excellent mechanical properties and stability in use, and shows promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of hydrogel patch technology, specifically to a self-energized gelatin-based hydrogel patch and its preparation method. Background Technology

[0002] This invention belongs to the field of medical wearable biomaterials and wound repair technology, specifically relating to a self-energized gelatin-based hydrogel patch for wound repair. As the largest barrier organ in the human body, the efficient repair of skin after injury has always been a core research direction in clinical medicine and biomaterials, especially chronic skin injuries such as diabetic foot ulcers, pressure ulcers, and postoperative refractory wounds, which are characterized by long healing cycles, easy recurrence and high relapse rates. These injuries not only severely reduce patients' quality of life but also place a heavy burden and pose significant challenges to the clinical diagnosis and treatment system.

[0003] Currently, commonly used wound repair materials in clinical practice are mainly traditional gauze and ordinary moisturizing hydrogel dressings. These materials can only achieve basic physical isolation and wound moisturizing protection, lacking the targeted therapeutic function to actively promote wound healing and cannot effectively intervene in the wound microenvironment. Their repair effect on chronic and difficult-to-heal wounds is very limited, and they are prone to adhesion to newly formed tissue during replacement, causing secondary damage to the wound. In recent years, physical repair technologies such as electrical stimulation and photothermal therapy have been proven to effectively accelerate the wound healing process. However, existing related treatment equipment generally relies on external power sources and large diagnostic and treatment instruments. The equipment is bulky and has poor portability, making it impossible to achieve continuous treatment in dynamic scenarios such as patients at home and during daily activities, which greatly limits its clinical application.

[0004] Meanwhile, existing single physical therapy modalities suffer from limited target points and repair efficiency, making it difficult to meet the multi-dimensional treatment needs of complex wounds. Furthermore, existing composite functional hydrogels used for wound repair generally suffer from poor component compatibility and insufficient mechanical properties. Their tensile strength and flexibility are ill-suited to the dynamic deformation of human skin, leading to issues such as detachment and poor interface adhesion with prolonged use. Moreover, most have the limitation of single-function application, failing to simultaneously achieve wound treatment and real-time monitoring of physiological status, thus hindering personalized, full-cycle wound management. Some composite materials also exhibit poor biocompatibility and insufficient long-term safety, severely restricting their clinical translation and large-scale application. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a self-energized gelatin-based hydrogel patch and its preparation method.

[0006] (II) Technical Solution A self-powered gelatin-based hydrogel patch comprises, from top to bottom, an upper encapsulation layer, a two-dimensional material / gelatin-based hydrogel functional layer, a conductive electrode layer, and a lower encapsulation layer. The two-dimensional material / gelatin-based hydrogel functional layer, by mass-volume ratio, contains 12% (w / v) gelatin as the hydrogel matrix, 5%-15% (w / v) two-dimensional material as the core conductive and photothermal conversion functional component, and also contains the plasticizer glycerol and the cross-linking agent transglutaminase. The two-dimensional material is Ti3C2MXene. The mass ratio of gelatin to glycerol is 1:1.5, and the mass ratio of gelatin to transglutaminase is 9:1. The two-dimensional material and gelatin interact through hydrogen bonds to form a uniformly dispersed three-dimensional network structure. The patch integrates three functions: self-powered electrical stimulation via triboelectric nanogenerator, near-infrared photothermal therapy, and flexible wearable physiological sensing. It can generate electrical energy through human mechanical movement without an external power source, achieving electro-thermal synergy to promote wound healing, while simultaneously monitoring human physiological activity signals in real time.

[0007] Preferably, the two-dimensional material further includes one or more of black phosphorus, molybdenum disulfide, and molybdenum diselenide.

[0008] Preferably, the two-dimensional material is Ti3C2MXene with a mass-to-volume ratio of 10% (w / v).

[0009] Preferably, both the upper and lower encapsulation layers are flexible encapsulation materials, the flexible encapsulation material is Ecoflex silicone rubber with a thickness of 0.5mm-1.5mm; the conductive electrode layer is copper conductive tape, which is bonded between the two-dimensional material / gelatin-based hydrogel functional layer and the lower encapsulation layer.

[0010] Preferably, the flexible encapsulation material further includes one or both of GelMA and AlgMA.

[0011] Preferably, under mechanical excitation of 60N pressure and 2Hz frequency, the patch has a peak output voltage of 163.7V and a peak output current of 8.1μA, and its electrical output performance shows no significant attenuation after 6000 cycles of mechanical excitation.

[0012] Preferably, the patch is at 808nm and 1W / cm. 2 Under near-infrared laser irradiation, the surface temperature rises to 58.3℃ within 300s, and maintains stable photothermal conversion reversibility after 10 light cycles.

[0013] Preferably, the fracture strain of the MXene / gelatin-based hydrogel functional layer reaches 450%, the patch material is non-cytotoxic, the cell survival rate is over 95%, and there is no in vivo or systemic toxicity.

[0014] Preferably, the preparation method of the self-energized gelatin-based hydrogel patch includes the following steps: Synthesis of S1.Ti3C2MXene nanosheets: Ti3AlC2MAX phase material was immersed in 40% HF solution and etched at 25°C for 3 days to remove the Al layer. After centrifugation and washing, the product was dispersed in 25% TPAOH aqueous solution and stirred for 3 days for intercalation and exfoliation. After centrifugation and washing again, a single-layer or few-layer Ti3C2MXene nanosheet dispersion was obtained. Preparation of S2.MXene / gelatin-based hydrogel: Gelatin was dissolved in deionized water at 50℃ at a mass-volume ratio of 12% (w / v), and 5%-15% (w / v) Ti3C2MXene nanosheet dispersion was added. After stirring and mixing evenly, glycerol was added at a mass ratio of gelatin to glycerol of 1:1.5, and transglutaminase was added at a mass ratio of gelatin to transglutaminase of 9:1. After vigorous stirring, a uniform MXene / gelatin composite hydrogel was formed. S3. Assembly of self-powered hydrogel patch: Mix Ecoflex silicone rubber components A and B at a 1:1 mass ratio, inject into a Teflon mold, and cure at 25°C to obtain an upper encapsulation layer and a lower encapsulation layer; cut MXene / gelatin composite hydrogel and place it between the two encapsulation layers; attach copper conductive tape as an electrode between the hydrogel and the lower encapsulation layer; apply Ecoflex mixture as an adhesive at the encapsulation interface; cure at 25°C for 12 hours to obtain a self-powered gelatin-based hydrogel patch.

[0015] Preferably, in step S1, the centrifugal washing after etching is performed by repeated centrifugation with deionized water until the pH value of the supernatant reaches 6-7; the centrifugal washing after intercalation and peeling is performed by centrifugation with deionized water to remove the unpeeled multilayer MXene precipitate and collect the upper single-layer or few-layer MXene nanosheet dispersion.

[0016] Preferably, in step S2, gelatin is dissolved in deionized water and kept at 50°C. After adding MXene dispersion, the mixture is stirred continuously for 30 minutes until it is evenly mixed. After adding glycerol and transglutaminase, the mixture is stirred vigorously at 50°C for 15 minutes. The mixture is then allowed to stand and cross-link to form an MXene / gelatin composite hydrogel. In step S3, the cut MXene / gelatin composite hydrogel has a size of 2cm×2cm×2mm, and the upper and lower encapsulation layers have a size of 3cm×3cm×1mm. During the curing process, a uniform pressure of 0.05MPa needs to be applied to the encapsulation patch.

[0017] (iii) Beneficial technical effects Compared with existing technologies, the beneficial effects of this invention are: A uniform and dense three-dimensional network structure is constructed through the hydrogen bonding interaction between MXene and gelatin, giving the hydrogel material excellent flexibility, stretchability and mechanical stability. It can fit well with human skin, perfectly adapt to the dynamic deformation needs of different body parts, and does not fall off or cause irritation even after long-term wear. It has excellent wearing comfort and usage stability.

[0018] This device efficiently integrates self-powered electrical stimulation and photothermal therapy, generating electricity through daily human activities without the need for an external power source. This enables continuous electrical stimulation intervention at the wound site. Combined with a highly efficient and stable photothermal conversion effect, the two work synergistically to significantly accelerate the wound healing process. At the same time, it can effectively inhibit the growth of bacteria in the wound and reduce the risk of infection. It has excellent repair effects on both acute and chronic refractory wounds.

[0019] The selected matrix materials and functional components all possess excellent biocompatibility, are non-cytotoxic and non-systemic toxic, and are safe and non-irritating when in contact with wound tissue, meeting the needs of long-term wound treatment. Furthermore, the patch structure of this invention exhibits excellent cyclic stability; its functions show no significant decline after long-term repeated use, demonstrating outstanding service life and reliability. Attached Figure Description

[0020] Figure 1 This is a flowchart of a method for preparing a self-powered gelatin-based hydrogel patch disclosed in this invention; Figure 2 This is the electrical output performance result of Example 1; Figure 3 This is the result of the self-powered power supply function demonstration in Example 1; Figure 4 These are the test results of the optical, photothermal, and mechanical properties of Example 1; Figure 5 This is the result of the effects of electrical stimulation and near-infrared photothermal therapy on mouse fibroblasts in Example 1; Figure 6 This is the result of the repair effect of Example 1 on the mouse in vivo wound model; Figure 7 This is the result of histological change analysis of the wound site after sample treatment in Example 1; Figure 8 This describes the expression of repair-related proteins in the wound tissue after sample treatment in Example 1. Figure 9 This is a functional demonstration result of the sample in Example 1 as a wearable sensor. Detailed Implementation

[0021] according to Figures 1 to 9 The specific embodiments of the present invention are as follows: This detailed embodiment discloses the complete technical solution of the self-energized gelatin-based hydrogel patch and its preparation method according to the present invention, aiming to enable those skilled in the art to fully understand the core concept of the present invention, repeat the technical solution of the present invention, and verify its technical effects. The scope of protection of the present invention includes, but is not limited to, reasonable adjustment schemes of specific parameters and process conditions described in this embodiment.

[0022] The self-powered gelatin-based hydrogel patch of the present invention is a layered composite flexible structure. From top to bottom, it is provided with an upper encapsulation layer, a two-dimensional material / gelatin-based hydrogel functional layer, a conductive electrode layer and a lower encapsulation layer. The whole is a fully flexible encapsulation structure that can fit the surface of human skin without gaps and adapt to dynamic deformations such as limb bending and muscle contraction. At the same time, it realizes the integrated functions of self-powered electrical stimulation, near-infrared photothermal synergistic wound repair and real-time sensing of human physiological activities.

[0023] Both the upper and lower encapsulation layers are made of flexible encapsulation materials. These materials possess excellent biocompatibility, high tensile strength, low modulus, and excellent triboelectronesia. They serve as both the encapsulation and protective layer of the patch, isolating the hydrogel functional layer from external environmental contamination and erosion, and the friction layer of the triboelectric nanogenerator, working in conjunction with the hydrogel functional layer to convert mechanical energy into electrical energy. The thickness of the encapsulation layer ranges from 0.5mm to 1.5mm, and can be adjusted according to the flexibility and electrical output performance requirements of the application scenario. The smaller the thickness, the higher the flexibility and contact-separation response sensitivity of the patch; the larger the thickness, the stronger the mechanical protection performance of the patch.

[0024] Under the technical concept of this invention, the two-dimensional material in the functional layer is not limited to Ti3C2MXene. Those skilled in the art can replace it with one or more of black phosphorus, molybdenum disulfide, and molybdenum diselenide, which have similar conductivity and photothermal conversion properties, according to actual needs, and the technical effects of this invention can be achieved in the same way. Similarly, the encapsulation layer material is not limited to Ecoflex silicone rubber. One or more of GelMA, AlgMA, and other biocompatible silicone rubbers or hydrogel materials with triboelectrone properties can also be selected. All of the above substitutions are within the scope of protection claimed by this invention.

[0025] The conductive electrode layer is made of highly conductive copper conductive tape with a thickness of 10μm-20μm. It is bonded between the two-dimensional material / gelatin-based hydrogel functional layer and the lower encapsulation layer. Its planar dimensions are slightly smaller than the hydrogel functional layer to ensure sufficient conductive contact with the hydrogel. At the same time, an extension section is reserved at one end of the electrode layer for use with external signal acquisition equipment to realize the output and acquisition of electrical signals. On the one hand, the electrode layer collects the charge generated by triboelectric generation and applies pulsed electrical signals to the wound site to realize electrical stimulation therapy. On the other hand, it collects the changes in electrical signals generated by the mechanical deformation of the patch to realize the sensing and monitoring of physiological activities.

[0026] The two-dimensional material / gelatin-based hydrogel functional layer is the core functional layer of the patch. Medical-grade gelatin serves as the matrix material for the three-dimensional hydrogel network, while two-dimensional materials are used as the core conductive and photothermal conversion functional components. Medical-grade glycerol is added as a plasticizer, and medical-grade transglutaminase as a crosslinking agent. Based on the total volume of the hydrogel system, the mass-to-volume ratio of gelatin is fixed at 12% w / v. At this concentration, gelatin can form a stable sol-gel transition system, which can be cured at room temperature and exhibits suitable flexibility at body temperature, demonstrating excellent skin adhesion. The Ti3C2MXene nanosheets have a mass-to-volume ratio of 5%-15% w / v. These are single-layer or few-layer nanosheets prepared using the HF etching-intercalation exfoliation method, with lateral dimensions of 1μm-5μm and sheet thicknesses of 1nm-5nm. They possess excellent near-infrared light absorption properties, metallic conductivity, and biocompatibility. The system can bind to gelatin molecules through hydrogen bonds, uniformly dispersed within the three-dimensional gelatin network. This serves both as a conductive filler, imparting excellent conductivity to the hydrogel and ensuring stable charge transfer and electrical stimulation output during triboelectric generation, and as a photothermal conversion medium, efficiently absorbing near-infrared light and converting it into heat energy for localized, controllable photothermal therapy. A fixed mass ratio of glycerol to gelatin of 1:1.5 significantly enhances the hydrogel's water retention and flexibility, preventing dehydration and cracking during long-term wear, while also reducing the hydrogel's modulus and improving its compatibility with the skin. A fixed mass ratio of transglutaminase to gelatin of 1:9 allows this enzyme to specifically catalyze the formation of covalent bonds between glutamine and lysine residues in gelatin molecules, resulting in a stable chemically cross-linked three-dimensional network. This significantly improves the hydrogel's mechanical stability, water resistance, and recyclability, preventing swelling and disintegration in bodily fluids.

[0027] The patch of this invention integrates three core functions, and its implementation principle is as follows: One function is self-powered electrical stimulation. The patch operates based on a triboelectric nanogenerator mechanism with a single electrode. The encapsulation layer is a triboelectrone material, and the two-dimensional material / gelatin hydrogel is the conductive electrode. When the human body applies periodic contact-separation mechanical forces to the patch during daily activities (such as breathing, limb bending, and muscle contraction), the interface between the encapsulation layer and the hydrogel functional layer undergoes periodic contact and separation. Equal amounts of triboelectric charges of opposite signs are generated at the interface. As the contact-separation process proceeds, the triboelectric charges induce periodic induced charges in the copper electrode layer, thereby forming a pulsed electrical signal output. It can convert the human body's mechanical energy into electrical energy without an external power source. The output pulsed electrical signal can simulate the human body's endogenous electric field, acting on the wound site to promote the directional migration and proliferation of fibroblasts and endothelial cells, and accelerate wound healing.

[0028] Secondly, it has a near-infrared photothermal therapy function. The two-dimensional material in the hydrogel has a strong near-infrared surface plasmon resonance effect, which can efficiently absorb near-infrared light in the 808nm band and convert light energy into heat energy, so that the local wound can be controlled to rise. On the one hand, it promotes local vasodilation and blood circulation and enhances cell metabolic activity. On the other hand, it can inhibit the growth of bacteria in the wound and reduce the risk of infection, forming a synergistic effect with electrical stimulation to promote repair.

[0029] Thirdly, it features flexible wearable physiological sensing capabilities. When the patch undergoes different forms and amplitudes of mechanical deformation, the amplitude and frequency of the electrical signals output by its triboelectric power generation will form a linear relationship with the mechanical deformation. By collecting changes in electrical signals, different human physiological activities such as coughing, swallowing, speaking, and joint bending can be accurately distinguished, enabling real-time monitoring of the patient's physiological state and the activity of the wound site. This provides data support for the rehabilitation assessment of wound healing and the adjustment of personalized treatment plans.

[0030] The method for preparing the patch of this invention includes three core steps: synthesis of MXene nanosheets, preparation of MXene / gelatin-based hydrogel, and patch assembly. The specific process is as follows: Synthesis of S1.Ti3C2MXene Nanosheets Ti3AlC2 MAX phase ceramic powder with a particle size of 300-400 mesh and a purity of ≥99% was selected as the raw material. The Ti3AlC2 powder was slowly added to a 40% HF solution at a solid-liquid ratio of 1g:20mL, with the entire process conducted in a fume hood to prevent splashing of the HF solution. After addition, the mixture was placed in a 25°C constant-temperature water bath shaker and etched at 150rpm for 3 days to ensure complete removal of the Al atomic layers in the MAX phase. After etching, the etched product was transferred to centrifuge tubes and repeatedly washed with deionized water at 3500rpm for 5 minutes each time. After each centrifugation, the supernatant was discarded, and deionized water was added again and the mixture was shaken until the pH of the supernatant stabilized between 6 and 7, yielding the etched multilayer phase. Ti3C2MXene precipitate was then dispersed in a 25% (w / w) tetrapropylammonium hydroxide (TPAOH) aqueous solution at a solid-liquid ratio of 1 g:10 mL. The mixture was stirred continuously at 300 rpm for 3 days at 25 °C to increase the interlayer spacing of MXene sheets through the intercalation effect of TPAOH and weaken the van der Waals forces between the sheets. After intercalation, the mixture was centrifuged and washed. First, it was centrifuged at 3500 rpm for 5 min to remove the precipitate that was not fully intercalated. The upper suspension was then centrifuged at 10000 rpm for 30 min. The supernatant was discarded, and the lower precipitate was redispersed with deionized water to obtain a single-layer or few-layer Ti3C2MXene nanosheet dispersion. The solid content of the dispersion was adjusted to 10 mg / mL, and the mixture was sealed and stored at 4 °C for later use.

[0031] Preparation of S2.MXene / gelatin-based hydrogel Medical-grade gelatin with a gelling strength of 240g Bloom was used. Gelatin powder was added to preheated deionized water at 50°C at a mass-to-volume ratio of 12% w / v. The solution was then placed in a 50°C constant temperature water bath and magnetically stirred at 300 rpm for 30 minutes until the gelatin was completely dissolved, forming a uniform and transparent gelatin solution. The temperature was maintained at 50°C throughout the process to prevent premature gelation of the gelatin. Following the target MXene mass-to-volume ratio of 5%-15% w / v, the corresponding amount of Ti3C2MXene nanosheet dispersion was added to the gelatin solution. The solution was maintained at 50°C and stirred at 300 rpm for 30 minutes to ensure uniform dispersion of the MXene nanosheets in the gelatin solution without significant agglomeration. Subsequently, medical-grade gelatin was added to the mixture at a mass ratio of 1:1.5 (medical grade to glycerol). Use grade glycerol and keep it warm and stir for 10 minutes to ensure that the glycerol and the mixture are fully mixed. Then, add medical grade transglutaminase with an enzyme activity ≥100U / g according to the mass ratio of gelatin to transglutaminase of 9:1. Heat to 55℃ and stir vigorously at 500rpm for 15 minutes to ensure that the crosslinking agent is evenly dispersed in the system. After stirring, place the mixture in a vacuum drying oven and degas it at room temperature for 5 minutes to remove air bubbles introduced during stirring. After degassing, inject the mixture into a custom polytetrafluoroethylene mold and let it stand at room temperature for 2 hours to complete the initial crosslinking. Then, transfer it to a 4℃ environment and refrigerate it for 12 hours to complete the full chemical crosslinking, and obtain MXene / gelatin-based composite hydrogel. After demolding, cut it to the target size for later use.

[0032] S3. Assembly of self-powered hydrogel patches Ecoflex 00-30 two-component silicone rubber was selected. Components A and B were weighed out in a 1:1 mass ratio and placed in a clean container. The mixture was stirred at 300 rpm for 5 minutes to ensure thorough mixing. The mixture was then placed in a vacuum drying oven and degassed at room temperature for 10 minutes to completely remove air bubbles introduced during mixing, preventing pinhole defects in the cured encapsulation layer. The degassed Ecoflex mixture was then injected into a pre-sized Teflon mold with grooves 0.5 mm to 1.5 mm deep. The mold was then placed horizontally and cured at 25°C for 12 hours. After demolding, a smooth and uniformly thick Ecoflex encapsulation film was obtained, serving as the upper and lower encapsulation layers, respectively. The lower encapsulation layer was then laid flat on a clean, horizontal work surface. A copper conductive tape is attached to the center of the patch, with a 0.5cm extension at one end as an electrode lead. Then, the MXene / gelatin-based hydrogel (2cm×2cm×2mm) cut in step S2 is smoothly attached to the copper conductive tape, ensuring complete contact between the hydrogel and the copper tape without gaps. The upper encapsulation layer is then aligned and placed over the hydrogel, completely encapsulating the hydrogel between the two encapsulation layers. At the edges of the upper and lower encapsulation layers, a degassed Ecoflex mixture is evenly applied as an adhesive. A uniform pressure of 0.05MPa is then applied to the entire patch to ensure that there are no air bubbles or gaps at the encapsulation interface. The patch is then cured at 25°C for 12 hours to complete the fully sealed encapsulation, resulting in a self-powered gelatin-based hydrogel patch.

[0033] The following are specific embodiments, wherein Embodiment 1 is the optimal embodiment of the present invention, and the other embodiments are control embodiments with parameter adjustments. All embodiments are carried out according to the above preparation method, only the core parameters are adjusted, as follows: Example 1

[0034] This embodiment is a preferred embodiment of the present invention. The self-energized gelatin-based hydrogel patch is prepared with a 1 mm thick Ecoflex film as the encapsulation layer. In the two-material / gelatin-based hydrogel functional layer, the two-material is Ti3C2MXene nanosheets with a mass-to-volume ratio of 10% w / v, a gelatin content of 12% w / v, a gelatin to glycerol mass ratio of 1:1.5, and a gelatin to glutamine transaminase mass ratio of 9:1.

[0035] The specific preparation steps are as follows: Synthesis of S1.Ti3C2MXene nanosheets: 5g of 300-mesh Ti3AlC2MAX phase powder was weighed and slowly added to 100mL of 40% HF solution. The mixture was etched at 25℃ and 150rpm for 3 days. After etching, the supernatant was washed by centrifugation at 3500rpm until the pH of the supernatant was 6.5. The etched precipitate was dispersed in 50mL of 25% TPAOH aqueous solution and stirred at 25℃ and 300rpm for 3 days for intercalation. After intercalation, the supernatant was collected by centrifugation at 3500rpm for 5min and then centrifuged at 10000rpm for 30min. The precipitate was redispersed with deionized water to obtain a monolayer Ti3C2MXene dispersion with a solid content of 10mg / mL, which was stored at 4℃.

[0036] Preparation of S2.MXene / gelatin-based hydrogel: Weigh 12g of medical-grade gelatin and add it to 100mL of deionized water at 50℃. Stir in a 50℃ water bath for 30min until completely dissolved. Add 100mL of 10mg / mL MXene dispersion to the gelatin solution and bring the volume up to 100mL. Keep warm at 50℃ and stir for 30min until uniformly dispersed. Add 18g of medical-grade glycerol and stir for 10min. Add 1.33g of transglutaminase and stir at 55℃ and 500rpm for 15min. After vacuum degassing for 5min, inject into a mold, let stand at room temperature for 2h, refrigerate at 4℃ for 12h, and cut into 2cm×2cm×2mm hydrogel sheets after demolding.

[0037] S3. Patch Assembly: Weigh 50g each of Ecoflex 00-30 A and B components, mix and stir for 5min, vacuum degas for 10min, inject into a Teflon mold with a depth of 1mm, cure at 25℃ for 12h, demold to obtain a 3cm×3cm×1mm encapsulation film; lay the lower encapsulation layer flat, attach a 1.8cm×1.8cm copper conductive tape, leave a 0.5cm lead-out end, attach the cut hydrogel sheet, cover with the upper encapsulation layer, coat the edges with Ecoflex mixture, apply a pressure of 0.05MPa, cure at 25℃ for 12h to obtain the target patch. Example 2

[0038] The only difference between this embodiment and Example 1 is that the mass-volume ratio of Ti3C2MXene nanosheets in the MXene / gelatin-based hydrogel functional layer is 5% w / v. The other raw material ratios, process steps and parameters are completely consistent with Example 1. Example 3

[0039] The only difference between this embodiment and Embodiment 1 is that in the two-material / gelatin-based hydrogel functional layer, black phosphorus is also used as the two-material component, with a mass-to-volume ratio of 15% w / v. The other raw material ratios, process steps, and parameters are completely consistent with those of Embodiment 1. Example 4

[0040] The only difference between this embodiment and Embodiment 1 is that, in the two-material / gelatin-based hydrogel functional layer, molybdenum disulfide is also selected as the two-material component, with a mass-to-volume ratio of 15% w / v; the flexible encapsulation material also includes GelMA, and the thickness of the upper and lower encapsulation layers is 0.5 mm. The remaining raw material ratios, process steps, and parameters are completely consistent with those of Embodiment 1. Example 5

[0041] The only difference between this embodiment and Embodiment 1 is that, in the two-material / gelatin-based hydrogel functional layer, molybdenum diselenide is also selected as the two-material component, with a mass-to-volume ratio of 15% w / v; the flexible encapsulation material also includes AlgMA, and the thickness of the upper and lower encapsulation layers is 1.5 mm. The remaining raw material ratios, process steps, and parameters are completely consistent with those of Embodiment 1.

[0042] The following are comparative examples used to compare and verify the advantages of the technical solution of the present invention. The basic process of each comparative example is the same as that of Example 1, only the core components and structure are adjusted: Comparative Example 1 This comparative example is a pure gelatin hydrogel patch without MXene. The hydrogel system contains only 12% w / v gelatin, glycerol and transglutaminase in the corresponding proportions, without adding MXene nanosheets. The remaining encapsulation structure, process steps and parameters are completely consistent with those in Example 1.

[0043] Comparative Example 2 This comparative example is an MXene / gelatin hydrogel patch without chemical crosslinking. No glutamine transaminase crosslinking agent is added to the hydrogel system. The other raw material ratios, encapsulation structures, process steps and parameters are completely consistent with those in Example 1.

[0044] Comparative Example 3 This comparative example is an unencapsulated MXene / gelatin hydrogel sheet. Only the MXene / gelatin-based hydrogel sheet of Example 1 was prepared. Ecoflex encapsulation and electrode attachment were not performed. There was no self-powered triboelectric structure. The other raw material ratios and hydrogel preparation processes were completely consistent with those of Example 1.

[0045] Comparative Example 4 This comparative example is an externally powered electrostimulation hydrogel patch. The hydrogel composition is completely consistent with that of Example 1. The encapsulation structure does not include the Ecoflex encapsulation layer for triboelectric power generation, but only uses ordinary medical polyurethane film for encapsulation. It provides electrical stimulation through an external DC power supply and has no self-powering function. The rest of the hydrogel preparation process is completely consistent with that of Example 1.

[0046] Performance Testing and Figure Descriptions For the samples prepared in the above embodiments and comparative examples, systematic multi-dimensional performance verification tests were conducted. Comprehensive testing and verification showed that the sample of Example 1 performed best in core indicators such as electrical output performance, photothermal conversion efficiency, mechanical stability, wound healing promotion effect, and sensing sensitivity, making it the optimal implementation scheme of this invention. All accompanying figures represent the performance characterization, functional demonstration, and control experimental results of the sample of Example 1 in this test. Specific test items, test results, and corresponding figures are explained below: 1. Electrical output performance test Test method: A linear motor was used to simulate the periodic movement of the human body. Mechanical forces of different frequencies (0.5-5Hz) and pressures (10-70N) were applied to the patch. The output voltage and current of the sample were measured by a high-precision electrometer (Keithley 6514). At the same time, 6000 cycles of testing were carried out to verify the long-term mechanical durability, as well as the functional verification of capacitor charging and low-power electronic device driving.

[0047] Test Results: Under optimal test conditions (60N pressure, 2Hz frequency), the sample of Example 1 achieved a peak output voltage of 163.7V and a peak output current of 8.1μA. After 6000 consecutive cycles, the electrical output signal attenuation was negligible, demonstrating excellent long-term mechanical durability. It could successfully drive six parallel LEDs to continuously illuminate, charge a 4.7μF commercial capacitor to 6V within 5 minutes, and stably drive a commercial electric timer, exhibiting excellent self-powering capability. While samples of Examples 2, 3, 4, and 5 possessed stable electrical output performance, their overall output performance was inferior to that of Example 1. Comparative Examples 1, 3, and 4 lacked self-powered electrical output capability, and Comparative Example 2 experienced hydrogel structure damage after cyclic testing, resulting in a significant decrease in electrical output performance. (Specific details are as follows...) Figure 2 As shown, (a) and (d) are the output voltage and current curves of hydrogel patches containing 5%, 10%, and 15% MXene under an external force of 60N and a frequency of 2Hz. It can be seen that the electrical output performance of Example 1 (10% MXene) is significantly better than that of the 5% and 15% MXene control groups. (b) and (e) show the chip output voltage and current curves for different Ecoflex package thicknesses under an external force of 60N and a frequency of 2Hz. It can be seen that Example 1 (1mm thickness) has the best overall output performance, balancing output performance and flexibility. (c) and (f) show the output voltage and current curves of the patch under different external forces at a frequency of 2Hz. It can be seen that the sample of Example 1 has a stable electrical output response in the range of 10-70N external force. (g) shows the output current curve of the sample of Example 1 at a working frequency of 3Hz, which confirms that it has a stable signal output at different frequencies; (h) shows the output voltage and current of the sample in Example 1 as a function of the load resistance, confirming its ability to drive low-power electronic devices; (i) is the cycle durability test curve of the sample in Example 1, which confirms its excellent long-term stability.

[0048] Figure 3 (A) is a demonstration of the self-powered power supply function of the sample of Example 1. The test curve of the sample of Example 1 charging a 4.7μF commercial capacitor is shown in the figure. The inset is an equivalent circuit diagram, which intuitively shows its energy storage and power supply capabilities.

[0049] 2. Photothermal and mechanical property testing Test method: Photothermal performance testing was performed using an 808nm near-infrared laser (power density 1W / cm²). 2 The sample surface was irradiated, and temperature changes were recorded using an infrared thermal imager. The effects of MXene content and encapsulation layer thickness on photothermal conversion were analyzed. At the same time, 10 light-on-off cycle tests were conducted to verify photothermal stability. The mechanical properties were tested using a universal testing machine to measure the stress-strain curves of the sample and characterize its tensile properties and flexibility.

[0050] Test Results: Under 808nm near-infrared laser irradiation, the surface temperature of the sample in Example 1 reached 58.3℃ within 300s, significantly better than the 5% MXene control group. 10% MXene was the optimal concentration; further increasing the MXene content to 15% did not significantly improve the heating effect. After 10 light-on-off cycles, the sample could still rapidly heat up and cool to room temperature, demonstrating excellent photothermal response reversibility and stability. Mechanical property tests showed that the fracture strain of the sample in Example 1 reached 450%, exhibiting excellent tensile strength and flexibility, adaptable to the dynamic deformation of human skin. The photothermal and mechanical properties of samples in Examples 2, 3, 4, and 5 were inferior to those of Example 1. Comparative Example 1 showed no significant photothermal heating effect, and Comparative Example 2 was prone to tensile fracture, exhibiting poor mechanical stability. Figure 4 Optical, photothermal and mechanical properties of the sample in Example 1, wherein (a) is the near-infrared light absorption curve of hydrogels with different MXene contents. It can be seen that the absorption rate of Example 1 (10% MXene) in the 808nm band is significantly higher than that of the 5% MXene group, and there is no significant difference from the 15% MXene group, confirming that 10% is the optimal addition amount. (b) Near-infrared light absorption curves of the sample from Example 1 with different Ecoflex package thicknesses; (c) shows the transmittance curves of Ecoflex with different thicknesses. It can be seen that the packaging thickness affects the transmittance and light absorption performance, confirming that the 1 mm thickness of Example 1 balances packaging performance and photothermal effect. (d) shows the photothermal heating curves of samples with different MXene contents and different encapsulation thicknesses. It can be seen that the heating rate and maximum temperature of the sample in Example 1 are optimal. (g) shows the heating and cooling curves of the sample from Example 1, confirming its rapid photothermal response capability; (h) is the light cycle test curve of the sample in Example 1, which confirms its excellent photothermal cycle stability; (i) shows the stress-strain curves of the Ecoflex elastomer membrane and the sample of Example 1, confirming its excellent stretchability and mechanical properties.

[0051] 3. In vitro cell viability and migration-promoting performance tests Test methods: NIH-3T3 fibroblasts were used for testing. Control group, NIR irradiation group, TESP electrical stimulation group, and TESP+NIR combined group were set up. Cell migration rate was analyzed by scratch assay and cell viability was detected by CCK-8 assay to verify the biocompatibility and cell migration promotion effect of the samples.

[0052] Test results: The TESP+NIR combined group of the sample in Example 1 achieved a scratch healing rate of 80% after 12 hours, which was significantly higher than that of the TESP group (50%), NIR group (20%) and blank control group (18%), confirming that its electro-thermal synergistic effect can significantly accelerate cell migration; the cell survival rate of each group was above 95%, with no significant difference, confirming that the sample of Example 1 was non-cytotoxic and had excellent biocompatibility. Figure 5 The effects of electrical stimulation and near-infrared photothermal on mouse fibroblasts in Example 1 are shown. Among them, (a) is a microscopic image of the cell scratch experiment of different treatment groups, which can be directly seen that the TESP+NIR combined group of Example 1 has the fastest scratch healing speed. (b) Quantitative analysis results of cell migration rate in different treatment groups, *p<0.05, confirming that the migration-promoting effect of the combined group is statistically significant; (c) shows the cell viability test results for different treatment groups, confirming that the sample of Example 1 has no cytotoxicity and excellent biosafety.

[0053] 4. Verification of in vivo wound repair effect Test methods: A full-thickness skin defect model of BALB / c mice was used. Mice were divided into control group, NIR group, TESP group, and TESP+NIR group (n=5 in each group). A circular full-thickness skin wound with a diameter of 7 mm was created. The wound healing was observed for 10 days. Histological staining (H&E, Masson's trichrome), immunofluorescence analysis, and blood biochemistry tests were performed to verify systemic toxicity.

[0054] Test Results: In Example 1, the TESP+NIR group had a residual wound area of ​​only 0.77% on day 10, significantly better than the TESP group (10.15%), NIR group (approximately 30%), and control group (approximately 30%). Histological analysis showed that the TESP+NIR group had an intact epithelial layer by day 5, with less inflammatory cell infiltration. By day 10, the epidermis had completely regenerated, with increased new hair follicles, collagen deposition reaching 60.3%, and microvascular density significantly higher than other groups. Immunofluorescence analysis showed that α-SMA and VEGF were most strongly expressed in the TESP+NIR group, confirming that they accelerate wound healing by activating fibroblast differentiation and angiogenesis. Blood tests showed that liver and kidney function indicators and blood cell counts were all within the normal range, confirming that the sample of Example 1 had no systemic toxicity and excellent in vivo biosafety. Figure 6 The repair effect of the sample of Example 1 on the mouse wound model is shown in (a), where (a) is a thermogram of temperature change at the wound site of the mouse with and without sample of Example 1 after 120s of irradiation with 808nm near-infrared laser, which can be seen intuitively. (b) The corresponding photothermal heating curve confirms its controllable heating capability; (c) shows gross images of mouse skin wounds in different treatment groups on days 0, 3, 5, 7 and 10. It can be seen that the TESP+NIR group in Example 1 had the fastest wound healing speed. (d) is a quantitative analysis curve of the proportion of residual wound area in different treatment groups, which confirms the excellent healing effect of combined treatment; (e) shows the weight change curve of mice during treatment, confirming that the sample has no acute systemic toxicity.

[0055] Figure 7 The histological changes of the wound site after sample treatment in Example 1 are analyzed. Among them, (a) is the H&E staining and Masson trichrome staining image of the wound tissue on day 5. It can be seen that the TESP+NIR group of Example 1 has the highest degree of re-epithelialization and the most new collagen deposition. (b) H&E staining, Masson's trichrome staining and CD31 immunofluorescence images of wound tissue on day 10. It can be seen that the epidermis of the combined group was completely regenerated, and the collagen deposition and microvascular formation effects were the best. (c) Quantitative analysis results of wound reepithelialization rate on day 5; (d) shows the quantitative analysis results of collagen deposition in the wound on day 10; (e) shows the quantitative analysis results of the average CD31 fluorescence intensity of the wound on day 10, confirming that the sample of Example 1 can significantly promote angiogenesis.

[0056] Figure 8The expression of repair-related proteins in wound tissue after sample treatment in Example 1 is shown. (a) shows the immunofluorescence images of α-SMA (red) and VEGF (green) in wound tissue of different treatment groups on day 10. Cell nuclei were stained with DAPI (blue). (b) and (c) show the quantitative analysis results of the average fluorescence intensity of α-SMA and VEGF, respectively, confirming that the sample of Example 1 can significantly upregulate the expression of repair-related proteins and accelerate wound healing.

[0057] 5. Performance testing of flexible wearable sensors Test method: The sample of Example 1 was attached to the throat, finger joints and back of the volunteers and mice respectively. The output electrical signals under different physiological movements were collected to verify its sensing performance.

[0058] Test Results: When the sample from Example 1 was applied to the throat, it could clearly distinguish different actions such as coughing, swallowing, and speaking, and output a characteristic voltage signal (amplitude 1-5V). When applied to the finger joints, the output voltage increased with the bending angle, showing good linear response. When applied to the back of a mouse, it could distinguish between static and active states in real time, accurately reflecting the mouse's activity and demonstrating excellent flexible physiological sensing performance. The sensing sensitivity of the other examples was lower than that of Example 1, and Comparative Examples 1-4 did not have stable sensing signal output capability.

[0059] Figure 9 This is a functional demonstration of the sample as a wearable sensor in Example 1. (a) shows the output electrical signal curves of the sample attached to the throat of a volunteer to monitor coughing, swallowing and speaking actions. The characteristic signal waveforms corresponding to different actions can be seen, with excellent discrimination. (b) The output voltage curves of the sample attached to the finger joint at different bending angles confirm its good linear response capability; (c) is the output electrical signal curve of the sample monitoring finger touch action; (d) The output electrical signal curves of the sample attached to the back of the mouse and monitored when the mouse was at rest and active, confirming that it can monitor the biological activity status in real time.

[0060] The basic performance comparison between the examples and the comparative examples is shown in the table below: Table 1 The following table compares the repair effects of full-thickness skin defects in mice in the examples and comparative examples: Table 2 As can be seen from the comprehensive test data in the two comparison tables, the performance differences among the samples are directly related to the formulation and structural design. Example 1, as the optimal solution of this invention, balances excellent self-powered electrical output performance, stable photothermal conversion efficiency, good mechanical flexibility, and long-term cyclic stability, and its in vivo and in vitro wound repair effects far exceed those of the other groups. Examples with minor parameter adjustments only show slight advantages in a single performance aspect, and their overall performance is far inferior to Example 1. The comparative examples, due to the lack of core functional components, chemical cross-linking structures, self-powered design, or encapsulation protection, either lose their core functions or exhibit extremely poor mechanical and cyclic performance, resulting in significantly weakened wound repair effects. This fully demonstrates that the formulation ratio and overall structural design of Example 1 are the core key to achieving multifunctional synergy and optimal performance.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-powered gelatin-based hydrogel patch, characterized in that, The patch comprises, from top to bottom, an upper encapsulation layer, a two-dimensional material / gelatin-based hydrogel functional layer, a conductive electrode layer, and a lower encapsulation layer. The two-dimensional material / gelatin-based hydrogel functional layer, by mass-volume ratio, contains 12% (w / v) gelatin as the hydrogel matrix, 5%-15% (w / v) two-dimensional material as the core conductive and photothermal conversion functional component, and also contains the plasticizer glycerol and the cross-linking agent transglutaminase. The two-dimensional material is Ti3C2MXene. The mass ratio of gelatin to glycerol is 1:1.5, and the mass ratio of gelatin to transglutaminase is 9:

1. The two-dimensional material and gelatin interact through hydrogen bonds to form a uniformly dispersed three-dimensional network structure. The patch integrates three functions: self-powered triboelectric nanogenerator for electrical stimulation, near-infrared photothermal therapy, and flexible wearable physiological sensing. It can generate electrical energy through human mechanical movement without an external power source, achieving electro-thermal synergy to promote wound healing, while simultaneously monitoring human physiological activity signals in real time.

2. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, The two-dimensional material also includes one or more of black phosphorus, molybdenum disulfide, and molybdenum diselenide.

3. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, The two-dimensional material is Ti3C2MXene with a mass-volume ratio of 10% (w / v).

4. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, Both the upper and lower encapsulation layers are made of flexible encapsulation materials, namely Ecoflex silicone rubber with a thickness of 0.5mm-1.5mm; the conductive electrode layer is made of copper conductive tape, which is bonded between the two-dimensional material / gelatin-based hydrogel functional layer and the lower encapsulation layer.

5. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, The flexible packaging material also includes one or both of GelMA and AlgMA.

6. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, Under mechanical excitation of 60N pressure and 2Hz frequency, the patch achieves a peak output voltage of 163.7V and a peak output current of 8.1μA. After 6000 cycles of mechanical excitation, the electrical output performance shows no significant attenuation.

7. The self-powered gelatin-based hydrogel patch according to claim 1, characterized in that, The patch operates at 808nm and 1W / cm². 2 Under near-infrared laser irradiation, the surface temperature rises to 58.3℃ within 300s, and maintains stable photothermal conversion reversibility after 10 light cycles.

8. A method for preparing a self-energized gelatin-based hydrogel patch as described in any one of claims 1-7, characterized in that, Includes the following steps: Synthesis of S1.Ti3C2MXene nanosheets: Ti3AlC2MAX phase material was immersed in 40% HF solution and etched at 25°C for 3 days to remove the Al layer. After centrifugation and washing, the product was dispersed in 25% TPAOH aqueous solution and stirred for 3 days for intercalation and exfoliation. After centrifugation and washing again, a single-layer or few-layer Ti3C2MXene nanosheet dispersion was obtained. Preparation of S2.MXene / gelatin-based hydrogel: Gelatin was dissolved in deionized water at 50℃ at a mass-volume ratio of 12% (w / v), and 5%-15% (w / v) Ti3C2MXene nanosheet dispersion was added. After stirring and mixing evenly, glycerol was added at a mass ratio of gelatin to glycerol of 1:1.5, and transglutaminase was added at a mass ratio of gelatin to transglutaminase of 9:

1. After vigorous stirring, a uniform MXene / gelatin composite hydrogel was formed. S3. Assembly of self-powered hydrogel patch: Mix Ecoflex silicone rubber components A and B at a 1:1 mass ratio, inject into a Teflon mold, and cure at 25°C to obtain an upper encapsulation layer and a lower encapsulation layer; cut MXene / gelatin composite hydrogel and place it between the two encapsulation layers; attach copper conductive tape as an electrode between the hydrogel and the lower encapsulation layer; apply Ecoflex mixture as an adhesive at the encapsulation interface; cure at 25°C for 12 hours to obtain a self-powered gelatin-based hydrogel patch.

9. The method for preparing the self-energized gelatin-based hydrogel patch according to claim 8, characterized in that, In step S1, the etching process involves repeated centrifugation with deionized water until the pH of the supernatant reaches 6-7. The centrifugation process after intercalation and peeling involves centrifugation with deionized water to remove the unpeeled multilayer MXene precipitate and collect the upper single-layer or few-layer MXene nanosheet dispersion.

10. The method for preparing the self-energized gelatin-based hydrogel patch according to claim 8, characterized in that, In step S2, gelatin is dissolved in deionized water and kept at 50°C. MXene dispersion is added and stirred continuously for 30 minutes until the mixture is uniform. Glycerin and transglutaminase are added and stirred vigorously at 50°C for 15 minutes. The mixture is then allowed to stand and cross-link to form an MXene / gelatin composite hydrogel. In step S3, the cut MXene / gelatin composite hydrogel has a size of 2cm×2cm×2mm, and the upper and lower encapsulation layers have a size of 3cm×3cm×1mm. During the curing process, a uniform pressure of 0.05MPa needs to be applied to the encapsulation patch.

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