Flexible TENG wound dressing based on freeze-dried PVDF-TrFE film and its preparation method and application

Abstract

The present invention discloses a flexible TENG bandage made based on freeze-dried PVDF-TrFE film, a preparation method and an application. The flexible TENG bandage is prepared by attaching a flexible nano friction generator to an adhesive tape. The method comprises: sputtering an ITO electrode on a PET substrate to obtain a first substrate electrode layer; preparing a PVDF-TrFE film; sequentially stacking the PVDF-TrFE film, a rubber gasket and a PA6 film to obtain a friction layer; sputtering an ITO electrode on a PET substrate, sputtering to form an interdigital electrode, and obtaining a second substrate electrode layer; attaching and electrically connecting to obtain a flexible nano friction generator TENG, and attaching it to an adhesive tape to obtain a flexible TENG bandage. The flexible TENG bandage of the present invention is easy to use, portable, easy to replace, and has a simple preparation method. It can be used for safe and non-invasive treatment and recovery of tendon injuries, and has great application prospects.

Description

Technical Field

[0001] The present invention relates to a flexible TENG wound dressing, and in particular to a flexible TENG wound dressing manufactured based on freeze-dried PVDF-TrFE film, a preparation method and an application thereof. Background Art

[0002] Tendons are ingenious mechanosensitive tissues with a hierarchical structure of a highly oriented extracellular matrix. Worldwide, more than 102.5 million people suffer tendon injuries each year due to external forces, overuse, or aging. Tendon injuries impair people’s quality of life and represent a significant healthcare burden worldwide. Surgical interventions with direct end-to-end repair using sutures and biologic or synthetic grafts are the gold standard for treatment, and despite their relative success, these repairs frequently fail to restore full tendon function. Following injury, disorganized tissue deposition leads to scar tissue formation, proteoglycan accumulation, and calcification, resulting in poor biomechanical properties and impaired function, which in turn trigger chronic inflammatory signaling pathways and progress to tendinopathy. Tendinopathy is a spectrum of diseases caused by a combination of extrinsic and intrinsic factors. Pathological changes in the tendon can range from molecular inflammation to fibrotic changes to overt tissue disruption and tearing. However, the underlying cellular and molecular mechanisms of tendinopathy remain unclear, and there are currently limited therapeutic strategies to improve tendon healing in affected patients.

[0003] Several studies have shown that mitochondria can influence the development of tissue and organ pathology by regulating cellular metabolism and modulating gene expression, affecting the activation of cell death pathways. Mitochondrial respiratory dysfunction has been shown to occur in osteoarthritis and affect tendon healing after tendon injury. Researchers found abnormalities in mitochondrial gene expression, membrane potential, and mitochondrial ultrastructure in degenerative tendons from patients with tendinopathy compared to healthy tendons. Mitochondrial dysfunction also appears to be associated with the development of deleterious tendon changes in a mouse model of supraspinatus tendinopathy induced by subacromial impingement, whereby mitochondrial function was improved after removal of the impingement in this animal model. Innovative solutions are needed to overcome the limitations of current tendon transplantation methods, and bioelectronic therapies have shown promise in the treatment of musculoskeletal diseases, accelerating functional recovery by activating tissue regeneration-specific signaling pathways. Several recent studies have revealed the great potential of electric fields in mediating cell migration, promoting collagen synthesis, and inducing successful wound healing through externally applied direct current stimulation. Electrical stimulation improves bone repair by modulating intracellular signal transduction pathways, promoting graft integration, inhibiting local inflammatory responses, and enhancing the use of stem cells in tissue engineering. BM-MSCs on lower output membranes had the lowest reactive oxygen species levels and the highest mitochondrial membrane potential, implying that these membranes provide optimal electrical charge for BM-MSCs proliferation and energy metabolism. In addition, when considering the potential of piezoelectric bioelectronic devices in regulating the progression of tendinopathy-related processes in vivo, the piezoelectric-derived electric fields generated during physiological exercise can provide additional bioelectric signal cues to activate tendon-specific regenerative pathways. However, the effect of electrical stimulation on mitochondrial regulation of tenocytes is still unclear. At the same time, electrical stimulation has a major disadvantage of external power consumption, which makes it difficult to meet the needs of miniaturization and lightweight of mobile electronic medical devices. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention provides a flexible TENG wound patch based on freeze-dried PVDF-TrFE film, a preparation method and an application. The emergence of friction nanogenerators (nano friction generators) provides an effective way to convert biological mechanical energy into electrical energy. The nano friction generator is a basic component that uses the coupling of triboelectric and electrostatic induction effects with thin-layer electrodes to achieve effective output of current, which can generate friction and form an outward current. It has been studied as a self-powered active pulse sensor because the amplitude and frequency of the output signal depend on the external mechanical stimulus. Wearable nano friction generators such as flexible, light film-shaped and self-powered devices play an important role in human motion monitoring and clinical applications. In addition, there are currently some self-powered electrical stimulation devices based on nano friction generators, such as enhancing the proliferation and migration of fibroblasts or promoting wound healing. Nano friction generators have been shown to enhance the proliferation and differentiation of bone cells. Therefore, the present invention provides a non-innovative therapy for tendon recovery treatment using nano friction generators, which provides a non-invasive, efficient, economical and safe solution for tendon recovery treatment and miniaturized flexible wearable tendon treatment systems.

[0005] The technical solution adopted by the present invention is:

[0006] 1. A flexible TENG wound dressing based on freeze-dried PVDF-TrFE film:

[0007] A flexible TENG bandage is prepared by attaching a flexible nano-friction generator TENG to a sticky tape. The area of ​​the flexible nano-friction generator TENG attached to the sticky tape is smaller than the area of ​​the sticky tape; the materials used in the nano-friction generator are all flexible materials.

[0008] The flexible nano friction generator TENG includes a first base electrode layer, a friction layer and a second base electrode layer which are stacked in sequence, the first base electrode layer is attached to an adhesive tape; the first base electrode layer is electrically connected to the second base electrode layer.

[0009] The first substrate electrode layer comprises a first polyethylene terephthalate (PET) substrate and a first indium tin oxide (ITO) electrode which are stacked. The first polyethylene terephthalate (PET) substrate is attached to the adhesive tape, and the first indium tin oxide (ITO) electrode is attached to the friction layer. The first indium tin oxide (ITO) electrode is electrically connected to the second substrate electrode layer.

[0010] The second substrate electrode layer includes a second indium tin oxide ITO electrode, a second polyethylene terephthalate PET substrate and a forked electrode which are sequentially stacked, the second indium tin oxide ITO electrode is attached to the friction layer; the second indium tin oxide ITO electrode is electrically connected to the forked electrode, and the forked electrode is electrically connected to the first indium tin oxide ITO electrode. The forked electrode can be a gold forked electrode.

[0011] The friction layer includes a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, a rubber gasket and a nylon 6PA6 film which are stacked in sequence; the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film is bonded to the first indium tin oxide ITO electrode of the first substrate electrode layer, and the nylon 6PA6 film is bonded to the second indium tin oxide ITO electrode of the second substrate electrode layer.

[0012] 2. A method for preparing a flexible TENG wound dressing comprises the following steps:

[0013] 1) Preparation of the first substrate electrode layer:

[0014] An indium tin oxide (ITO) target material is sputtered on one side of a first polyethylene terephthalate (PET) substrate by magnetron sputtering to form a layer of a hollow first indium tin oxide (ITO) electrode, thereby preparing a first substrate electrode layer.

[0015] 2) Preparation of friction layer:

[0016] The PVDF-TrFE film was prepared by freeze drying in a desktop freeze dryer; the PVDF-TrFE film, rubber gasket and nylon 6PA6 film were stacked and laminated in sequence to prepare a friction layer; the nylon 6PA6 film was prepared by solution casting.

[0017] 3) Preparation of the second substrate electrode layer:

[0018] A layer of hollow second indium tin oxide ITO electrode is formed on one side of the second polyethylene terephthalate (PET) substrate by sputtering an indium tin oxide (ITO) target material by magnetron sputtering, and a layer of hollow interdigital electrode is formed on the other side of the second polyethylene terephthalate (PET) substrate by sputtering a gold target material by magnetron sputtering, thereby preparing a second substrate electrode layer.

[0019] 4) Preparation of flexible TENG wound dressing:

[0020] The PVDF-TrFE film of the friction layer and the nylon 6PA6 film are respectively adhered to the first indium tin oxide ITO electrode and the second indium tin oxide ITO electrode; the second indium tin oxide ITO electrode is electrically connected to the interdigital electrode, and the interdigital electrode is electrically connected to the first indium tin oxide ITO electrode to obtain a flexible nano friction generator TENG, and then the other side of the first polyethylene terephthalate PET substrate of the flexible nano friction generator TENG is attached to an adhesive tape to prepare a flexible TENG bandage.

[0021] In the step 2), the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE is prepared by freeze drying to obtain a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, as follows:

[0022] The vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE is uniformly dissolved in dimethyl sulfoxide DMSO, and is sequentially heated in a water bath and magnetically stirred, and then frozen and continuously dried to obtain a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film.

[0023] The method comprises the steps of uniformly dissolving the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE in dimethyl sulfoxide (DMSO), heating in a water bath and magnetic stirring in sequence, and then freezing and continuing to dry and freeze. Specifically, 0.1 to 1 g of the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE is dissolved in 0.1 to 20 ml of dimethyl sulfoxide (DMSO), heating in a water bath at 30 to 50° C., stirring with a magnetic stirrer for 6 to 12 hours, pouring into a directional freezing container, freezing at -80° C. for 2 to 8 hours until completely frozen and solidified, and finally continuing to freeze-dry for 24 to 48 hours in a vacuum environment at -50° C. using a desktop freeze dryer to obtain a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film.

[0024] The flexible nano friction generator TENG is a cubic structure, and the length, width and height of the flexible nano friction generator TENG are specifically 0.5cm×0.5cm×0.2cm; the sticky tape, the first polyethylene terephthalate PET substrate, the first indium tin oxide ITO electrode, the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, the rubber gasket and the nylon 6PA6 film, the second indium tin oxide ITO electrode, the second polyethylene terephthalate PET substrate and the interdigital electrodes are all square sheet structures, and the length, width and height of the sticky tape are specifically 1.5cm×0.5cm×100um; the length, width and height of the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film and the nylon 6PA6 film are specifically 0.5cm×0.5cm×150um, and the length, width and height of the first polyethylene terephthalate PET substrate and the second polyethylene terephthalate PET substrate are specifically 0.5cm×0.5cm×200um.

[0025] 3. Application of a flexible TENG bandage:

[0026] The flexible TENG bandage is used for tendon recovery. The adhesive tape is placed on the top layer to adhere the entire flexible TENG bandage to the wound; the interdigital electrodes are placed on the bottom layer and connected to the indium tin oxide ITO electrodes with wires to transmit the electric field to the wound.

[0027] The beneficial effects of the present invention are:

[0028] 1) The nano friction generator used in the present invention is a safe power source that can avoid the dangers of operating a traditional high-voltage power source.

[0029] 2) The nano-friction generator used in the present invention is made of flexible materials and can generate sufficiently strong output in a small size and generate sufficient electric field after conversion by the interdigital electrodes, making it an ideal choice for non-invasive treatment of tendon injuries.

[0030] 3) The use of the present invention does not require surgery and is non-invasive throughout the process, which can greatly reduce the risk, time cost and economic cost of treatment.

[0031] 4) The finally prepared nano friction generator uses a band-aid type design, which is easy to use, portable and easy to replace.

[0032] 5) The preparation method is simple and the materials are readily available, which is conducive to cost control and industrial production.

[0033] 6) The prepared nano friction generator can be used for the treatment and recovery of tendon injuries.

[0034] 7) This paper provides an efficient, economical and safe solution for miniaturized wearable tendon treatment system, which has great application prospects.

[0035] The pulsed electrical stimulation generated by the nano-friction generator of the present invention can restore the function of degenerated tendon stem cells and enhance their biological function, increase the influx of calcium ions into tendon stem cells, change mitochondrial permeability, and activate the DRP-1 or MIRO-1 signaling pathway, thereby activating the oxidative cell phosphorylation process, increasing the production of ATP, and promoting cell differentiation and regeneration ability, thereby achieving the effect of promoting tendinopathy repair non-invasively. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the interface of the flexible TENG wound dressing of the present invention;

[0037] Figure 2 This is a scanning electron microscope test image of the PVDF-TrFE film of the present invention;

[0038] Figure 3 This is a Fourier transform infrared spectrometer test chart of the PVDF-TrFE film of the present invention;

[0039] Figure 4 Schematic diagram of the output voltage of the flexible TENG wound dressing of the present invention at different frequencies;

[0040] Figure 5 Schematic diagram of the output voltage generated by the flexible TENG bandage of the present invention when applied to the tendon of a mouse;

[0041] Figure 6 It is a partial schematic diagram of the gold interdigital electrode observed under a microscope of the present invention;

[0042] Figure 7 Schematic diagram of an in vitro stimulation device for generating electrical stimulation on cells by a nano friction generator of the present invention;

[0043] Figure 8 This is an electron microscope image of the mitochondrial morphological changes observed in the tendon stem cells of the control group and the electrical stimulation group of the present invention;

[0044] Fig. 9 It is a schematic diagram of cytoskeleton staining of tendon stem cells in the control group and the electrical stimulation group of the present invention;

[0045] Fig.10 Schematic diagram of histological staining of Achilles tendon in the control group and the electrical stimulation group of the present invention. DETAILED DESCRIPTION

[0046] The present invention is further described in detail by the following non-limiting examples. It should be understood that these examples are only some preferred technical solutions, and the scope of protection requested by the claims is not limited to the following examples.

[0047] The specific embodiments of the present invention are as follows:

[0048] Embodiment 1:

[0049] Preparation of a first substrate electrode layer: sputtering an indium tin oxide (ITO) target material on one side of a first polyethylene terephthalate (PET) substrate by a magnetron sputtering method to form a layer of a hollow first indium tin oxide (ITO) electrode, thereby preparing a first substrate electrode layer; Preparation of a friction layer: freeze-drying a vinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE) in a desktop freeze dryer to obtain a vinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE) film, specifically, dissolving 1 g of the vinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE) in 10 ml of dimethyl sulfoxide (DMSO) SO, heated in a water bath at 30°C, then stirred with a magnetic stirrer for 12 hours, then poured into a directional freezing container, frozen at -80°C for 8 hours until completely frozen and solidified, and finally continued to freeze-dry for 36 hours in a vacuum environment of -50°C using a desktop freeze dryer to obtain a PVDF-TrFE film; the PVDF-TrFE film, the rubber gasket and the nylon 6PA6 film were stacked and laminated in sequence to prepare a friction layer; the nylon 6PA6 film was prepared by solution casting. The second substrate electrode layer was prepared: on one side of the second polyethylene terephthalate PET substrate, an indium tin oxide ITO target was sputtered by magnetron sputtering to form a layer of a hollow second indium tin oxide ITO electrode, and on the other side of the second polyethylene terephthalate PET substrate, a gold target was sputtered by magnetron sputtering to form a layer of a hollow interdigital electrode, thereby preparing the second substrate electrode layer. Preparation of flexible TENG bandage: The PVDF-TrFE film and the nylon 6PA6 film of the friction layer are respectively attached to the first indium tin oxide ITO electrode and the second indium tin oxide ITO electrode; the second indium tin oxide ITO electrode is electrically connected to the interdigital electrode, and the interdigital electrode is electrically connected to the first indium tin oxide ITO electrode to obtain a flexible nano friction generator TENG, and then the other side of the first polyethylene terephthalate PET substrate of the flexible nano friction generator TENG is attached to an adhesive tape to prepare a flexible TENG bandage, and the electrode connection is encapsulated with polylactic acid-glycolic acid, such as Figure 1 shown.

[0050] The scanning electron microscope and Fourier transform infrared spectrometer characteristics of Example 1 are as follows: Figure 2and Figure 3 Scanning electron microscopy results show that the film has a longitudinal lamellar structure with high porosity. Figure 3 The absorbance and wavelength of the Fourier transform infrared spectrum of PVDF-TrFE film prepared by freeze drying. PVDF-TrFE can have different polymorphic phases, depending on the molecular chain conformation during the manufacturing process. These phases are usually represented by α, β and γ. For the α phase, the peaks are usually at 763 and / or 614 cm -1 , 1403cm -1 and 1430cm -1 The peak of the β phase is usually at 840 cm -1 , 1275cm -1 , 1400cm -1 For the γ phase, the peak is about 510 cm -1 , 1234cm -1 and 1400cm -1 .

[0051] like Figure 4 As shown, the nano friction generator composed of PVDF-TrFE film and PA6 film has a fixed contact force of 50N and a contact classification distance of 5mm. When the frequency increases from 2Hz to 6Hz, the open circuit voltage increases from 710±3V to an output voltage of 964±4V, indicating the influence of frequency on the output of the nano friction generator. When the frequency rises, the output will increase to a certain extent, reaching a saturation voltage of 964±4V at 5-6Hz.

[0052] The friction layer films are all 2cm×2cm in size. The nano friction generator composed of PA6 film and freeze-dried PVDF-TrFE film generates pulse output through contact separation mode, where the interval is less than 1mm, the film size is 0.5cm×0.5cm, and the thickness is 150um. After testing, Figure 5 As shown, the nano friction generator bandage of this embodiment can generate an output of 10 to 20 V at the tendon of mice.

[0053] like Figure 6 As shown, the characterization under an optical microscope shows that the finger width of the interdigitated electrode is 25um and the spacing is 100um.

[0054] Next, we tested triboelectric stimulation therapy for regulating mitochondrial function in rat tendon stem cells. Figure 7As shown, the mechanical signal is converted into an electrical signal by the nano-friction generator, which is then transmitted to the interdigital electrodes after passing through a rectifier, and finally transmitted to the cells through an electric field. Primary tendon stem cells were extracted from the Achilles tendons of rats with tendinopathy and normal rats, and the nano-friction generator in Example 1 was used to rectify the interdigital electrodes covered with polylactic acid-glycolic acid at a rate of 1*10 6 The cells were inoculated onto the electrode plate at a cell density of 1.5 cells / ml and cultured for 12 hours. The cells were processed by transmission electron microscopy to observe the morphological changes of mitochondria in tendon stem cells before and after electrical stimulation. Figure 8 As shown, the mitochondria of tendon stem cells extracted from the Achilles tendon with worsening lesions were swollen, smaller in size and had shallow mitochondrial ridges. After electrical stimulation, the mitochondrial swelling in the tendon stem cells returned to health and the mitochondrial ridges became deeper, indicating that the mitochondrial function in the tendon stem cells was restored.

[0055] Next, the frictional electric stimulation therapy was tested for the regulation of the morphology and proliferation of rat tendon stem cells. The above-mentioned nano friction generator was used to culture rat tendon stem cells. A rectifier was used to rectify the current generated by the friction generator, and then it was connected to the interdigital electrodes. A layer of polylactic acid-glycolic acid with a thickness of about 5 mm was poured on the interdigital electrodes to isolate the current that might be generated between the culture medium and the electrodes. 6 The cells were inoculated onto polylactic-co-glycolic acid culture plates and cultured for 12 h and 20 h, respectively, before adding phalloidin dye for cytotoxicity / proliferation staining. Fig. 9 As shown, the cell proliferation ability of the electrical stimulation group was significantly stronger than that of the control group, and electrical stimulation could also change the cell morphology to a spindle shape, indicating that the electrical stimulation generated by the nano-friction generator has the effect of promoting the proliferation and differentiation of tendon stem cells.

[0056] Finally, the histological results of the friction power patch promoting the regeneration and repair of collagen in the rat Achilles tendon were tested. A rat Achilles tendinopathy model was established using type 1 collagenase induction. Seven days after the injection of collagenase, the nano-friction generator in Example 1 was used for treatment. The nano-friction generator patch was placed on the skin surface of the rat's right Achilles tendon, and then the rat was placed on a treadmill for 30 minutes of running exercise every day at a speed of about 5m / min, driving the nano-friction generator in Example 1 to slide in the vertical direction, applying a pulse current to the damaged Achilles tendon for 30 minutes to treat the rat. Fig.10 As shown, the histological results of Achilles tendon in the electrical stimulation group showed that the structure of collagen fibers was significantly improved compared with the control group, the collagen arrangement was more orderly, and the inflammatory infiltration of the tissue was significantly reduced.

[0057] The flexible nano-friction generators TENG prepared in Example 1 are all of cubic structure, and the length, width and height dimensions of the flexible nano-friction generators TENG are specifically 0.5cm×0.5cm×0.2cm; the sticky tape, the first polyethylene terephthalate PET substrate, the first indium tin oxide ITO electrode, the polyvinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, the rubber gasket and the nylon 6PA6 film, the second indium tin oxide ITO electrode, the second polyethylene terephthalate PET substrate and the interdigitated electrodes are all of square sheet structures, and the length, width and height dimensions of the sticky tape are specifically 1.5cm×0.5cm×100um; the length, width and height dimensions of the polyvinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film and the nylon 6PA6 film are specifically 0.5cm×0.5cm×150um, and the length, width and height dimensions of the first polyethylene terephthalate PET substrate and the second polyethylene terephthalate PET substrate are specifically 0.5cm×0.5cm×200um.

[0058] The present invention proposes an electrical stimulation therapy that converts the pulse electricity generated by a friction nanogenerator into an electric field to treat damaged tendons. The method uses a small friction nanogenerator patch to generate pulsed direct current to directly stimulate degenerated tendon stem cells in tendinopathy, promote the influx of intracellular calcium ions, appropriately increase the mitochondrial membrane potential, and increase the level of mitochondrial oxidative phosphorylation to improve the function of intracellular mitochondria, activate downstream tendon injury repair-related signal pathways, and further achieve the treatment of tendinopathy injury repair. Frictional electric repair therapy shows excellent tissue regeneration ability and biosafety, can significantly improve the prognosis of patients with tendinopathy, and has broad application prospects in the field of sports injury repair. It can provide a patch for use in the preparation of DC friction nanogenerators and wearable devices for tendinopathy treatment.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the scope of protection of the invention.

Claims

1. A flexible TENG wound dressing made based on freeze-dried PVDF-TrFE film, characterized by: A flexible TENG bandage prepared by attaching a flexible nano-friction generator TENG to an adhesive tape; The flexible nano friction generator TENG comprises a first substrate electrode layer, a friction layer and a second substrate electrode layer which are sequentially stacked, the first substrate electrode layer being attached to an adhesive tape; the first substrate electrode layer being electrically connected to the second substrate electrode layer; The first substrate electrode layer comprises a first polyethylene terephthalate (PET) substrate and a first indium tin oxide (ITO) electrode which are stacked, the first polyethylene terephthalate (PET) substrate is attached to the adhesive tape, and the first indium tin oxide (ITO) electrode is attached to the friction layer; the first indium tin oxide (ITO) electrode is electrically connected to the second substrate electrode layer; The second substrate electrode layer comprises a second indium tin oxide ITO electrode, a second polyethylene terephthalate PET substrate and an interdigital electrode which are sequentially stacked, and the second indium tin oxide ITO electrode is attached to the friction layer; The second indium tin oxide ITO electrode is electrically connected to the interdigital electrode, and the interdigital electrode is electrically connected to the first indium tin oxide ITO electrode; The friction layer comprises a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, a rubber gasket and a nylon 6 PA6 film which are stacked in sequence, the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film is bonded to the first indium tin oxide ITO electrode of the first substrate electrode layer, and the nylon 6 PA6 film is bonded to the second indium tin oxide ITO electrode of the second substrate electrode layer; The flexible nano friction generator TENG is a cubic structure, and the length, width and height of the flexible nano friction generator TENG are specifically 0.5cm×0.5cm×0.2cm; the sticky tape, the first polyethylene terephthalate PET substrate, the first indium tin oxide ITO electrode, the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, the rubber gasket and the nylon 6 PA6 film, the second indium tin oxide ITO electrode, the second polyethylene terephthalate PET substrate and the interdigital electrodes are all square sheet structures, and the length, width and height of the sticky tape are specifically 1.5cm×0.5cm×100um; the length, width and height of the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film and the nylon 6 PA6 film are specifically 0.5cm×0.5cm×150um, and the length, width and height of the first polyethylene terephthalate PET substrate and the second polyethylene terephthalate PET substrate are specifically 0.5cm×0.5cm×200um.

2. The method for preparing the flexible TENG wound dressing according to claim 1, characterized in that: The method comprises the following steps: 1) Preparation of the first base electrode layer: Sputtering an indium tin oxide (ITO) target material on one side of a first polyethylene terephthalate (PET) substrate by magnetron sputtering to form a layer of a hollow first indium tin oxide (ITO) electrode, thereby preparing a first substrate electrode layer; 2) Preparation of friction layer: The PVDF-TrFE film is prepared from the PVDF-TrFE film by freeze drying; the PVDF-TrFE film, the rubber gasket and the nylon 6 PA6 film are stacked and laminated in sequence to prepare a friction layer; 3) Preparation of the second base electrode layer: A layer of hollow second indium tin oxide ITO electrode is formed by sputtering an indium tin oxide ITO target material on one side of the second polyethylene terephthalate PET substrate by magnetron sputtering, and a layer of hollow interdigital electrode is formed by sputtering a gold target material on the other side of the second polyethylene terephthalate PET substrate by magnetron sputtering, thereby preparing a second substrate electrode layer; 4) Preparation of flexible TENG wound dressing: The PVDF-TrFE film and the nylon 6 PA6 film of the friction layer are respectively attached to the first indium tin oxide ITO electrode and the second indium tin oxide ITO electrode; the second indium tin oxide ITO electrode is electrically connected to the interdigital electrode, and the interdigital electrode is electrically connected to the first indium tin oxide ITO electrode to obtain a flexible nano friction generator TENG, and then the other side of the first polyethylene terephthalate PET substrate of the flexible nano friction generator TENG is attached to an adhesive tape to prepare a flexible TENG bandage; In the step 2), the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE is prepared by freeze drying to obtain a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, as follows: The PVDF-TrFE copolymer is uniformly dissolved in dimethyl sulfoxide (DMSO), heated in a water bath and stirred magnetically, and then frozen and freeze-dried to obtain a PVDF-TrFE copolymer film; The process of uniformly dissolving the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE in dimethyl sulfoxide DMSO, heating in a water bath and magnetic stirring in sequence, then freezing and continuing freeze drying, specifically, dissolving 0.1-1 g of the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE in 0.1-20 ml of dimethyl sulfoxide DMSO, heating in a water bath at 30-50° C., stirring with a magnetic stirrer for 6-12 hours, then pouring into a directional freezing container, freezing at -80° C. for 2-8 hours until completely frozen and solidified, and finally continuing to freeze dry in a desktop freeze dryer at -50° C. in a vacuum environment for 24-48 hours to obtain a vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film; The flexible nano friction generator TENG is a cubic structure, and the length, width and height of the flexible nano friction generator TENG are specifically 0.5cm×0.5cm×0.2cm; the sticky tape, the first polyethylene terephthalate PET substrate, the first indium tin oxide ITO electrode, the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film, the rubber gasket and the nylon 6 PA6 film, the second indium tin oxide ITO electrode, the second polyethylene terephthalate PET substrate and the interdigital electrodes are all square sheet structures, and the length, width and height of the sticky tape are specifically 1.5cm×0.5cm×100um; the length, width and height of the vinylidene fluoride-trifluoroethylene copolymer PVDF-TrFE film and the nylon 6 PA6 film are specifically 0.5cm×0.5cm×150um, and the length, width and height of the first polyethylene terephthalate PET substrate and the second polyethylene terephthalate PET substrate are specifically 0.5cm×0.5cm×200um.

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