A pyroelectric hydrogel with promoting wound healing and its preparation method and application

Abstract

This invention discloses a thermoelectric hydrogel that promotes wound healing, its preparation method, and its application, belonging to the field of biomedical technology. The thermoelectric hydrogel dressing of this invention uses glutaraldehyde-crosslinked water-soluble chitosan gel as a matrix, with silver selenide nanoparticles and tea polyphenols uniformly doped within the matrix. The mass fraction of the silver selenide nanoparticles is 0.1wt%~5.0wt%, and the mass fraction of the tea polyphenols is 0.01~1wt%. The thermoelectric hydrogel dressing provided by this invention can utilize the natural temperature difference between the skin wound and the environment to continuously generate thermoelectric voltage based on the Seebeck effect, enhancing the endogenous electric field of the damaged wound. Simultaneously, the tea polyphenols scavenge excess reactive oxygen species and inhibit inflammatory responses, synergistically accelerating wound healing. This dressing requires no external power source, has good biocompatibility, can adhere to the skin wound to maintain a moist healing environment, is safe and non-toxic, and possesses both electrical stimulation and antioxidant / anti-inflammatory functions.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a thermoelectric hydrogel based on the Seebeck effect that promotes wound healing, its preparation method, and its application. Background Technology

[0002] As one of the most important organs in the human body, the skin is extremely vulnerable to external damage. Impaired wound healing can lead to chronic wounds and even serious complications such as infection. The endogenous electric field generated after skin injury plays a central role in guiding cell migration, proliferation, and tissue repair, while the weakening of the endogenous electric field associated with chronic wounds hinders the healing process. Currently used wound repair methods in clinical practice still suffer from problems such as limited functionality, low healing efficiency, and limited effectiveness for chronic, refractory wounds. Traditional electrical stimulation devices for promoting healing rely on external power sources, are bulky, and complex to use, failing to achieve portable and continuous wound intervention. Among existing self-powered healing technologies, triboelectric nanogenerators suffer from incomplete interfacial contact and limited electrical output, while piezoelectric devices rely on external mechanical stimulation and cannot provide continuous and stable electrical stimulation when the patient is at rest. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a self-powered thermoelectric hydrogel based on the Seebeck effect that promotes wound healing, its preparation method and application, in order to solve the problems of the single function of existing wound repair dressings, the dependence of traditional electrical stimulation devices on external power sources, and the unstable output of existing self-powered technologies. The core advantages of the electrothermal hydrogel of this invention are: (1) Silver selenide nanoparticles, as n-type thermoelectric materials, have excellent thermoelectric conversion performance and biocompatibility at room temperature, and can use the natural 12K temperature difference between the wound and the environment to stably output thermoelectric voltage, thereby enhancing the endogenous electric field of the damaged wound; (2) The porous hydrogel matrix constructed from water-soluble chitosan can maintain a moist healing environment for the wound, and has good exudate absorption capacity, mechanical flexibility and tissue adhesion, and can achieve long-term slow release of tea polyphenols; (3) Tea polyphenols can efficiently remove excess reactive oxygen species from the wound, inhibit excessive inflammatory response, and work synergistically with thermoelectric stimulation to accelerate the wound healing process from multiple dimensions.

[0004] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a self-powered thermoelectric hydrogel, which uses glutaraldehyde-crosslinked water-soluble chitosan gel as a matrix, and uniformly dops silver selenide nanoparticles and antioxidants in the matrix, wherein the mass fraction of the silver selenide nanoparticles is 0.1wt%~5.0wt% and the mass fraction of the antioxidants is 0.01~1wt%.

[0005] Based on the above technical solution, the antioxidant further includes tea polyphenols.

[0006] Based on the above technical solution, the silver selenide nanoparticles are β-Ag2Se with an orthorhombic crystal structure and an average particle size of 100~300nm, exhibiting excellent thermoelectric conversion performance and biosafety at room temperature.

[0007] Based on the above technical solution, the mass fraction of the silver selenide nanoparticles is 0.5wt%~2.0wt%, and the mass fraction of the antioxidant is 0.1~1wt%.

[0008] Based on the above technical solution, the thermoelectric hydrogel further has a porous structure, a swelling rate of ≥100% after 48 hours, a tensile strain of ≥100%, a tensile strength of ≥30kPa, a compressive strain of ≥60%, and a compressive strength of ≥0.2MPa, which is suitable for wound adhesion requirements of active parts such as joints.

[0009] Based on the above technical solution, the thermoelectric hydrogel further utilizes the Seebeck effect to convert heat energy into electrical energy under the temperature difference between the skin wound and the environment. It can stably output thermoelectric voltage under a 12K temperature difference, with a Seebeck coefficient ≤ -15.0 mV·K. -1 Electrical conductivity ≥24.0 mS·cm -1 Power factor ≥ 7.0 mV·cm -1 K 2 .

[0010] Based on the above technical solution, further, the cumulative release rate of antioxidants in the thermoelectric hydrogel is ≥90% over 14 days.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned self-powered thermoelectric hydrogel, comprising the following steps: (1) Preparation of hydrogel premix: Add silver selenide nanoparticles, antioxidants and water-soluble chitosan to water, stir evenly, and defoam and degas; (2) To prepare a thermoelectric hydrogel, add glutaraldehyde aqueous solution to the mixed solution prepared in step (1), mix well and pour into a mold, cross-link and form to obtain a self-powered thermoelectric hydrogel with wound healing function.

[0012] Based on the above technical solution, further, in step (1), the mass fraction of silver selenide nanoparticles in the aqueous solution is 0.1wt%~5.0wt%, the mass fraction of antioxidant is 0.01~1wt%, and the mass fraction of water-soluble chitosan is 8.0~12.0wt%.

[0013] Based on the above technical solution, further, the defoaming and degassing in step (1) specifically refers to ultrasonic defoaming and degassing.

[0014] Based on the above technical solution, further, the silver selenide nanoparticles in step (1) are prepared by reducing selenium dioxide (SeO2) to obtain selenium nanoparticles (Se NPs), and then reacting them with silver nitrate (AgNO3) to obtain silver selenide nanoparticles.

[0015] Based on the above technical solution, further, the preparation of silver selenide nanoparticles in step (1) includes the following steps: slowly pouring an aqueous solution containing 0.001~0.02 g / mL selenium dioxide and 0.001~0.02 g / mL β-cyclodextrin into an equal volume of an aqueous solution containing 0.001~0.02 g / mL ascorbic acid, reacting for 2~10 h, washing and collecting the selenium nanoparticle precipitate, dispersing the obtained selenium nanoparticle precipitate in ethylene glycol, then mixing it with an ethylene glycol solution containing dissolved silver nitrate, reacting for 0.5~5 h, adding an aqueous solution containing 0.01~0.05 g / mL ascorbic acid, continuing the reaction for 0.5~5 h, washing, collecting the precipitate, and drying to obtain the final product.

[0016] Based on the above technical solution, further, the mass ratio of selenium nanoparticle precipitate to silver nitrate in the ethylene glycol mixed solution is 1:10 to 1:1, and the concentration of silver nitrate is 0.01 to 0.05 g / mL; the volume of ascorbic acid aqueous solution added is 20% to 80% of the volume of the ethylene glycol mixed solution.

[0017] Based on the above technical solution, further, the concentration of the glutaraldehyde aqueous solution in step (2) is 0.1~1%, and the volume ratio of the glutaraldehyde aqueous solution to the mixed solution is 1:10~1:1.

[0018] Thirdly, the present invention provides the application of the above-mentioned self-powered thermoelectric hydrogel in the preparation of dressings that promote wound healing.

[0019] Based on the above technical solution, the dressing is further applied to the skin defect wound, and the temperature difference between the wound and the environment continuously generates thermoelectric voltage to enhance the endogenous electric field of the wound. At the same time, by releasing tea polyphenols to remove reactive oxygen species and inhibit inflammatory response, the dressing accelerates wound healing.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The thermoelectric hydrogel dressing of the present invention can utilize the natural temperature difference between the skin wound and the environment to continuously generate thermoelectric potential based on the Seebeck effect, enhance the endogenous electric field of the damaged wound, promote fibroblast proliferation and migration, and accelerate angiogenesis and collagen deposition; at the same time, the dressing can release tea polyphenols for a long time, effectively remove excess reactive oxygen species from the wound, downregulate pro-inflammatory factors and upregulate anti-inflammatory factors, inhibit excessive inflammatory response, and synergistically accelerate wound healing, thereby accelerating wound re-epithelialization and tissue remodeling, and improving the quality and efficiency of wound healing.

[0021] 2. The thermoelectric hydrogel dressing of the present invention does not require an external power source, has good biocompatibility, can adhere to the skin wound to maintain a moist healing environment, is safe and has no toxic side effects, and has dual functions of electrical stimulation and anti-oxidation and anti-inflammation. Attached Figure Description

[0022] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0023] Figure 1 SEM images of silver selenide nanoparticles (A) and thermoelectric hydrogel surface (B) prepared in Example 1.

[0024] Figure 2 The release curve of tea polyphenols in the thermoelectric hydrogel prepared in Example 1 over 14 days is shown.

[0025] Figure 3 The Fourier transform infrared spectrum of the hydrogel prepared in Example 1.

[0026] Figure 4 The graph shows the results of thermoelectric performance testing of the thermoelectric hydrogel prepared in Example 1.

[0027] Figure 5 The graph shows the ratio of dead cells in Calcein-AM / PI live / dead cell staining of the thermoelectric hydrogel prepared in Example 1.

[0028] Figure 6 The CCK-8 microplate reader OD of the thermoelectric hydrogel prepared in Example 1 for three consecutive days 450nm Graph showing the results of the detection value (A) and cell viability on day 1 (B).

[0029] Figure 7 The image shows the results of cell migration promoted by the thermoelectric hydrogel prepared in Example 1.

[0030] Figure 8 The image shows the results of the thermoelectric hydrogel prepared in Example 1 promoting wound healing in rats.

[0031] Figure 9 The figure shows the results of pro-inflammatory factors (TNF-α, IL-1β) and anti-inflammatory factors (IL-10, TGF-β) expressed in rat skin wound tissue using the thermoelectric hydrogel prepared in Example 1 on days 3 and 14.

[0032] Figure 10 The images show H&E staining (A) and Masson staining (B) of rat skin wound tissue prepared using the thermoelectric hydrogel of Example 1 on day 14, as well as the quantitative statistical results of epidermal thickness and collagen deposition.

[0033] Figure 11Immunohistochemical staining and quantitative results of CD31, α-SMA and ColⅠ in rat skin wound tissue prepared using the thermoelectric hydrogel of Example 1.

[0034] Figure 12 H&E stained sections of other tissues from rats using the thermoelectric hydrogel prepared in Example 1. Detailed Implementation

[0035] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0036] Example 1 This embodiment provides a method for preparing a self-powered thermoelectric hydrogel dressing with wound-healing function, including the following steps: (1) Preparation of silver selenide nanoparticles (Ag2Se NPs): 1g of selenium dioxide (SeO2) (Shanghai Maclean Biochemical Technology Co., Ltd.) and 1g of β-cyclodextrin (Shanghai Maclean Biochemical Technology Co., Ltd.) were dissolved in 100mL of deionized water to obtain solution A; 1g of L-ascorbic acid (Shanghai Maclean Biochemical Technology Co., Ltd.) was dissolved in 100mL of deionized water to obtain solution B; after complete dissolution, solution A was slowly poured into solution B, and after reacting for 4 hours, the mixture was washed and centrifuged repeatedly with water and anhydrous ethanol (8000rpm, 5min), the precipitate was collected and freeze-dried. Take 0.1 g of the prepared precipitate, i.e., selenium nanoparticles (Se NPs), and 0.4 g of silver nitrate (AgNO3) (Sinopharm Chemical Reagent Co., Ltd.), dissolve them separately in 20 mL of ethylene glycol, and then mix them. After reacting for 1 hour, add 20 mL of L-ascorbic acid aqueous solution (0.0385 g / mL). After reacting at room temperature for 1 hour, wash and centrifuge repeatedly with water and anhydrous ethanol (8000 rpm, 5 min), collect the precipitate and freeze-dry it to obtain silver selenide nanoparticles (average particle size of about 200 nm).

[0037] (2) Mix 1.0 wt% silver selenide nanoparticles, 0.2 wt% tea polyphenols (Maya reagent) and 10.0% water-soluble chitosan powder (Qingdao Honghai Biotechnology Co., Ltd., molecular formula (C6H)). 11 NO4) n Dissolve in 5 mL of deionized water, stir at room temperature until completely dissolved, and then degas and defoam by ultrasonication to obtain a uniform hydrogel premix. (3) Add 2 mL of 0.5% glutaraldehyde aqueous solution to the above premixed solution, mix quickly and pour into the mold, cross-link and mold at room temperature, and obtain the self-powered thermoelectric hydrogel dressing after demolding.

[0038] The morphology and physicochemical properties of the prepared silver selenide nanoparticles (Ag2Se NPs) and thermoelectric hydrogel were characterized. Scanning electron microscopy (SEM) showed that the silver selenide nanoparticles had a uniform morphology and an average diameter of 200 nm. X-ray diffraction (XRD) analysis confirmed that they conformed to the Ag2Se orthorhombic crystal system (PDF no. 24-2041). SEM images of the freeze-dried hydrogel showed that it had a rich porous structure, which facilitated the slow release of tea polyphenols, resulting in a release rate of 95% after 14 days (5.0 g of accurately weighed sample was placed in 500 mL of PBS buffer (pH = 7.4, 37℃). At preset time points of 0.5, 1, 2, 4, 8, 12, and 14 days, 2.0 mL of the release solution was taken out and immediately replenished with isothermal and equal volume of fresh PBS. The released solution was filtered through a 0.22 μm microporous membrane, and the content was detected and the release percentage was calculated). Fourier transform infrared spectroscopy confirmed that tea polyphenols (wavelength: 1220 nm) and silver selenide nanoparticles (wavelength: 570 nm) were successfully incorporated into the hydrogel matrix. Mechanical property tests showed that the hydrogel had a tensile strain >110% and a tensile strength of 40 kPa, a compressive strain >76% and a compressive strength of 0.4 MPa, and possessed good flexibility and tissue conformation.

[0039] Example 2 The thermoelectric hydrogel prepared in Example 1 was evaluated for its thermoelectric performance using an electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd., Chi760F) and a constant-temperature heating stage (Dongguan Bangyuan Electronics Co., Ltd., BY1010). The heating stage was heated to 37°C (310.15 K, simulating human body temperature). Under a temperature difference of 12 K between the heating stage and room temperature (simulating the temperature difference between a human wound and the environment), the hydrogel could stably output a thermoelectric potential of approximately 216 mV within 400 seconds, with a Seebeck coefficient reaching -18.29 mV·K. -1 The highest conductivity is 25.98 mS·cm. -1 The power factor is as high as 8.70 mV·cm. -1 K 2 It can stably generate continuous electrical stimulation to meet the electrical stimulation needs of wound repair.

[0040] Human skin fibroblasts (HSF) were used as model cells to conduct in vitro biocompatibility, proliferation and cell migration promotion experiments (scratch assay) of the thermoelectric hydrogel prepared in Example 1.

[0041] Simple chitosan hydrogel group (CS, prepared according to the method of Example 1, with only soluble chitosan added in step (2)), tea polyphenol-chitosan hydrogel group (CT, prepared according to the method of Example 1, with only tea polyphenol and soluble chitosan added in step (2)), silver selenide-chitosan hydrogel group (CA, prepared according to the method of Example 1, with only silver selenide nanoparticles and soluble chitosan added in step (2)), thermoelectric hydrogel group (CTA, thermoelectric hydrogel prepared in Example 1); the prepared CS, CT, CA and CTA hydrogels (circular, 15 mm in diameter, 3 mm thick) were weighed and sterilized under ultraviolet light. Then, the hydrogels were immersed in a composite culture medium (84% DMEM + 15% fetal bovine serum + 1% penicillin-streptomycin solution) at a ratio of 1 g / mL. Then the hydrogels were incubated in a 37°C incubator for 48 hours. After incubation, the hydrogel was removed from the culture medium and the resulting extract was stored at 4°C for further use.

[0042] The cytotoxicity assay of the thermoelectric hydrogel was performed using human skin fibroblasts (HSFs). HSFs were then incubated at 2... 10 4 Cells were seeded at a density of 100 µL / mL in 96-well plates. After cell attachment, the original composite culture medium (84% DMEM + 15% fetal bovine serum + 1% penicillin-streptomycin solution) was aspirated, and PBS (pH=7.4) was gently added along the inner wall of each well for 1 min. After aspirating the PBS, the prepared extraction solution (composite culture medium was added for the control group) was added, and the cells were incubated at 37°C for 24 h. After incubation, the extraction solution was aspirated, and PBS was gently added along the inner wall of each well for 1 min. After aspirating the PBS, 100 µL of Calcein-AM / PI live / dead cell staining solution was added to each well, and the cells were incubated at 37°C in the dark for 30 min. The staining solution was then aspirated, and the cells were rinsed with 1 mL of PBS for 1 min before being observed and photographed under a confocal microscope.

[0043] The effect of thermoelectric hydrogels on the proliferation of human skin fibroblasts (HSFs) was assessed using a cell counting kit (CCK-8). HSFs cells (5... 10 4Cells (cells / mL) were seeded in 96-well plates, with 100 µL added to each well. After cell attachment, the original composite medium was aspirated, and 100 µL of hydrogel extract (composite medium was added to the control group) was added to each well. The plates were incubated at 37°C for 24, 48, and 72 hours, respectively. Subsequently, 10 μL of CCK-8 enhancement solution was added to each well, and the plates were incubated for an additional hour at 37°C. The cell proliferation effect of the thermoelectric hydrogel was assessed by measuring the OD value at 450 nm using a microplate reader. Wells containing composite medium served as the control group, and wells containing only composite medium without cells served as the blank. Cell viability (%) was estimated using the following formula: Cell viability (%) = (OD) s - OD b ) / (OD c - OD b ) × 100% OD s OD c and OD b These represent the OD values ​​of the experimental group (CS, CT, CA, CTA), the control group, and the blank group, respectively.

[0044] The effect of thermoelectric hydrogels on the migration of human skin fibroblasts (HSFs) was evaluated in HSF cells. HSF cells were sputtered at 4... 10 5 Cells were seeded at a density of cells / mL in 12-well plates and cultured in culture medium for 12 hours to form a cell monolayer. A straight line was drawn vertically and with uniform force on the surface of the monolayer cells. After adding the extract (the control group added basal culture medium, i.e., containing only DMEM) and culturing for different times (0h, 12h, 24h), cell migration was observed using an inverted optical microscope.

[0045] Calcein-AM / PI live / dead cell staining results showed that ( Figure 5 The HSF cells treated with this hydrogel showed good viability, no significant cytotoxicity, and excellent biocompatibility; CCK-8 assay results showed that... Figure 6 The cell proliferation activity of the hydrogel-treated group was significantly enhanced for three consecutive days, with a cell survival rate of 138.2% on day 1, which was significantly better than that of the blank control group and the chitosan hydrogel group alone; the scratch repair experiment results showed that ( Figure 7 Thermoelectric hydrogel-treated cells (CA, CTA) achieved nearly 100% scratch closure within 24 hours, demonstrating that it can significantly promote fibroblast migration.

[0046] Example 3 Healthy male Sprague-Dawley (SD) rats were selected to construct a full-thickness skin defect model with a diameter of 10 mm on the back, and a wound treatment experiment was carried out. The rats were randomly divided into a blank control group (without any dressing), a simple chitosan hydrogel group (CS, prepared according to the method of Example 1, with only soluble chitosan added in step (2)), a tea polyphenol-chitosan hydrogel group (CT, prepared according to the method of Example 1, with only tea polyphenol and soluble chitosan added in step (2)), a silver selenide-chitosan hydrogel group (CA, prepared according to the method of Example 1, with only silver selenide nanoparticles and soluble chitosan added in step (2)), and a thermoelectric hydrogel group (CTA, thermoelectric hydrogel prepared in Example 1). After modeling, each group was covered with the corresponding dressing, and the dressing was changed every 3 days. The observation was continued for 14 days.

[0047] Experimental results are as follows Figure 8 As shown, the wound healing rate in the CTA group was significantly better than that in the other groups, with a wound healing rate of 98.28% on day 14; ELISA results of skin wound tissue on days 3 and 14 showed ( Figure 9 The CTA group significantly downregulated the expression of pro-inflammatory factors TNF-α and IL-1β in the wound, while significantly upregulating the expression of anti-inflammatory factors IL-10 and TGF-β, confirming its excellent anti-inflammatory effect; H&E staining of skin wound tissue on day 14 showed ( Figure 10 The CTA group showed continuous and intact epidermis with clear layers, complete reepithelialization and high maturity, and numerous newly formed hair follicles, sebaceous glands and other skin appendages; Masson staining showed ( Figure 10 In the CTA group, collagen fibers were dense and regularly arranged, highly matching the collagen orientation of normal skin, and the collagen maturity and deposition were significantly better than in other groups. Immunohistochemical staining results for CD31, α-SMA, and ColⅠ confirmed this. Figure 11 The CTA group significantly promoted wound angiogenesis, myofibroblast activation, and type I collagen synthesis, comprehensively improving wound healing quality. Meanwhile, H&E staining of the major organs of rats showed no obvious histological lesions, and the rats exhibited normal weight gain, confirming the excellent in vivo biocompatibility of this hydrogel.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-powered thermoelectric hydrogel, characterized in that, The matrix is ​​a water-soluble chitosan gel crosslinked with glutaraldehyde. Silver selenide nanoparticles and antioxidants are uniformly doped into the matrix. The mass fraction of the silver selenide nanoparticles is 0.1wt%~5.0wt%, and the mass fraction of the antioxidants is 0.01~1wt%.

2. The self-powered thermoelectric hydrogel according to claim 1, characterized in that, The antioxidants include tea polyphenols; the silver selenide nanoparticles are β-Ag2Se with an orthorhombic crystal structure and an average particle size of 100~300nm.

3. The self-powered thermoelectric hydrogel according to claim 1, characterized in that, The aforementioned thermoelectric hydrogel has a porous structure, a swelling rate ≥100% after 48 hours, a tensile strain ≥100%, a tensile strength ≥30 kPa, a compressive strain ≥60%, and a compressive strength ≥0.2 MPa. The thermoelectric hydrogel can stably output a thermoelectric voltage under a temperature difference of 12 K, with a Seebeck coefficient ≤-15.0 mV·K. -1 Electrical conductivity ≥24.0 mS·cm -1 Power factor ≥ 7.0 mV·cm -1 K 2 The cumulative release rate of antioxidants in the thermoelectric hydrogel is ≥90% over 14 days.

4. The method for preparing the self-powered thermoelectric hydrogel according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Preparation of hydrogel premix: Add silver selenide nanoparticles, antioxidants and water-soluble chitosan to water, stir evenly, and defoam and degas; (2) To prepare a thermoelectric hydrogel, add glutaraldehyde aqueous solution to the mixed solution prepared in step (1), mix well, pour into a mold, cross-link and form to obtain a self-powered thermoelectric hydrogel.

5. The preparation method according to claim 4, characterized in that, In step (1), the mass fraction of silver selenide nanoparticles in the aqueous solution is 0.1wt%~5.0wt%, the mass fraction of antioxidant is 0.01~1wt%, and the mass fraction of water-soluble chitosan is 8.0~12.0wt%.

6. The preparation method according to claim 4, characterized in that, The silver selenide nanoparticles mentioned in step (1) are prepared by reducing selenium dioxide (SeO2) to obtain selenium nanoparticles (Se NPs), and then reacting them with silver nitrate (AgNO3) to obtain silver selenide nanoparticles.

7. The preparation method according to claim 6, characterized in that, The preparation of silver selenide nanoparticles in step (1) includes the following steps: an aqueous solution containing 0.001~0.02 g / mL selenium dioxide and 0.001~0.02 g / mL β-cyclodextrin is slowly poured into an equal volume of an aqueous solution containing 0.001~0.02 g / mL ascorbic acid. The reaction is carried out for 2~10 h. After washing, the selenium nanoparticle precipitate is collected. The obtained selenium nanoparticle precipitate is dispersed in ethylene glycol and then mixed with an ethylene glycol solution containing dissolved silver nitrate. The reaction is carried out for 0.5~5 h. An aqueous solution containing 0.01~0.05 g / mL ascorbic acid is added, and the reaction is continued for 0.5~5 h. After washing, the precipitate is collected and dried to obtain the final product.

8. The preparation method according to claim 7, characterized in that, The mass ratio of selenium nanoparticle precipitate to silver nitrate in the ethylene glycol mixed solution is 1:10 to 1:1, and the concentration of silver nitrate is 0.01 to 0.05 g / mL; the volume of ascorbic acid aqueous solution added is 20% to 80% of the volume of the ethylene glycol mixed solution.

9. The preparation method according to claim 4, characterized in that, The concentration of the glutaraldehyde aqueous solution in step (2) is 0.1-1%, and the volume ratio of the glutaraldehyde aqueous solution to the mixed solution is 1:10-1:

1.

10. The use of the self-powered thermoelectric hydrogel according to any one of claims 1-3 in the preparation of dressings that promote wound healing.

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