Photo-thermal composite hydrogel patch as well as preparation method and application thereof

Abstract

The invention discloses a photo-thermal composite hydrogel patch and a preparation method and application thereof.The hydrogel patch is of a three-dimensional latticed porous structure formed by taking methylacryloyl gelatin (GelMA) and methylacryloyl hyaluronic acid (HAMA) as matrixes, loading niobium carbide nano-particles (Nb2CNPs) and vinipofen (VP) and conducting 3D printing or casting molding, the hydrogel patch is named as VP-Nb2C-coated GelMA / HAMA (VNGH) hydrogel patch for short. The VNGH has good photo-thermal antibacterial property, oxidation resistance and reepithelization promoting function, can significantly improve the quality of mouse diabetic wound healing, and provides a new thought and strategy for realizing scar-free healing of diabetic wounds.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a photothermal composite hydrogel patch and a preparation method and application thereof. Background Art

[0002] Wounds that fail to fully heal and achieve anatomical and functional integrity for more than one month are generally defined as chronic wounds. Common types of chronic wounds include varicose ulcers, arterial ulcers, pressure ulcers, and diabetic foot ulcers. Delayed wound healing in diabetic patients can be attributed to multiple factors, including high local blood glucose levels, vascular lesions, neuropathy, bacterial infection, and tissue hypoxia. Delayed wound healing in diabetic patients is primarily associated with persistent hyperglycemia, impaired angiogenesis, imbalanced extracellular matrix metabolism, infection, and inflammation. A chronic hyperglycemic environment increases the accumulation of advanced glycation end-products (AGEs) in tissues. AGEs bind to receptors and activate the NF-κB pathway, triggering an inflammatory response that exacerbates tissue damage. Excessive glucose levels downregulate VEGF expression by inhibiting the HIF-1α pathway, leading to impaired angiogenesis and insufficient oxygen and nutrient supply to the wound, thus exacerbating poor wound healing in diabetic patients. Furthermore, bacterial infection is one of the greatest challenges to chronic wound healing. Microbial proliferation can induce increased tissue damage, prolong the inflammatory response, and delay wound healing. In order to prevent wound infection, antibiotics are widely used in clinical practice. However, excessive use or even misuse of antibiotics has accelerated the development of bacterial resistance and the emergence of multidrug-resistant pathogens. The development speed of antibiotics lags far behind the speed of bacterial resistance mutation, so the development of An antibacterial treatment that is safe, effective, and less likely to cause bacterial resistance has become a focus of global attention.

[0003] In order to solve the above problems in the prior art, it is necessary to develop a hydrogel patch for repairing diabetic wounds. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a photothermal composite hydrogel patch, which has good photothermal antibacterial, antioxidant, and re-epithelialization promoting functions, can significantly improve the quality of diabetic wound healing in mice, and provide new ideas and strategies for achieving scar-free healing of diabetic wounds.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: In a first aspect of the present invention, a photothermal composite hydrogel patch is provided, comprising: Using methacryloylated gelatin (GelMA) and methacryloylated hyaluronic acid (HAMA) as the matrix, loaded with niobium carbide nanoparticles (Nb2CNPs) and verteporfin (VP), and formed into a three-dimensional grid-like porous structure by 3D printing or casting, referred to as VP-Nb2C@GelMA / HAMA (VNGH) hydrogel patch.

[0006] Furthermore, the photothermal composite hydrogel patch has a pore size of 150-250 μm and a porosity of 30%-50%.

[0007] Furthermore, the mass ratio of the GelMA to HAMA is 350-450:1.

[0008] In a second aspect of the present invention, a method for preparing the photothermal composite hydrogel patch is provided, the method comprising: GelMA, HAMA, and photoinitiator LAP were dissolved in PBS, and then Nb2CNPs dispersion and VP solution were added, mixed and filtered. GelMA was dissolved in the solution containing photoinitiator LAP, and HAMA, Nb2CNPs dispersion and VP solution were added in sequence, mixed and filtered. VP-Nb2C@GelMA / HAMA (VNGH) hydrogel patch was obtained by 3D printing or casting molding.

[0009] Furthermore, the photoinitiator LAP (Lithium Phenyl-2,4,6-trimethylbenzoylphosphinate) is a photosensitizing compound used to trigger the photocuring reaction in hydrogel preparation. Specifically, it generates reactive free radicals under specific wavelengths of light, which promote cross-linking and polymerization of the GelMA and HAMA matrices, forming a stable three-dimensional structure.

[0010] Furthermore, the concentration of the GelMA after being dissolved in PBS is 5%-15% (w / v), the concentration of the HAMA after being dissolved in PBS is 0.01%-0.05% (w / v), and the volume ratio of the GelMA to the HAMA is 350-450:1.

[0011] As a preferred embodiment, the concentration of GelMA after being dissolved in PBS is 5%-15% (w / v), within which both fluidity and printing accuracy can be taken into consideration; More preferably, the concentration of GelMA dissolved in PBS is 10%. A 3D-printed hybrid hydrogel patch with a 10% GelMA concentration exhibits adequate adhesion and ductility, and its application to wounds is not limited by wound location or skin flatness. After preparing the various hydrogel solutions required for 3D printing, the inventors conducted trial prints to observe the printing performance of the hydrogel solutions at different GelMA concentrations. 3D printing parameters were set to a 10 mm square with a packing density of 40%. Trial prints revealed that hydrogel hybrid solutions with 5% and 8% GelMA concentrations exhibited low viscosity and good fluidity, but the material in the syringe easily overflowed from the nozzle under air pressure, making it difficult to control the trace width. A hydrogel hybrid solution with a 15% GelMA concentration exhibited higher viscosity and poorer fluidity, making it prone to uneven extrusion or nozzle clogging during printing, resulting in intermittent traces and reduced printing precision. Therefore, considering both fluidity and printing precision, we selected a hydrogel hybrid solution with a 10% GelMA concentration for subsequent 3D printing and experiments.

[0012] Furthermore, the working concentration of Nb2CNPs in the Nb2CNPs dispersion is 500-1500 μg / mL.

[0013] Furthermore, in the VP solution, the working concentration of VP is 3-500 μg / mL.

[0014] Furthermore, 405 nm light curing is used in the 3D printing.

[0015] In a third aspect of the present invention, there is provided use of the composite hydrogel in a dressing for treating diabetic wounds.

[0016] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: 1. The present invention provides a photothermal composite hydrogel patch. The 3D-printed VNGH hydrogel scaffold patch exhibits excellent swelling, water retention, and degradation properties, absorbing 10 times its own weight in liquid within 24 hours. Its loose, porous three-dimensional network structure meets the requirements of an ideal wound dressing: good breathability, maintaining a moist wound environment, absorbing excess exudate, and suitable degradation capacity. Furthermore, drug release curve results show that approximately 55% of VP is released within 48 hours, and VP release continues until the eighth day.

[0017] 2. Innovation of this invention: For the first time, Nb2C NPs and VP are integrated into a dual-matrix grid structure, solving the vicious cycle of "infection-oxidative stress-fibrosis" in diabetic wounds through triple synergy, and photothermal antibacterial and drug controlled release synergistically in time and space: Nb2C NPs photothermal effect: Under 808 nm laser irradiation, the temperature of the VNGH group rose to 65.5℃ in 3 minutes ( Figure 7 -B), which was 35% higher than that of the NGH group (48.6℃), achieving an antibacterial rate of >99% (Staphylococcus aureus inhibition zone 18 mm, Figure 11 ), animal experiment results show that VNGH can effectively promote wound healing in diabetic mice. Hair follicle regeneration density: 40 / mm 2 ( Figure 16 -B), far exceeding the current level of diabetic wound treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Figure 3 shows the morphological characteristics and elemental mapping of Nb2C NPs. A. Representative TEM image of Nb2C; B. Representative SEM image of Nb2C; C. EDS analysis of Nb2C.

[0019] Figure 2 Structural characteristics of Nb2C NPs. A. X-ray diffraction pattern of Nb2C; B. Zeta potential of Nb2C; C. Particle size analysis of Nb2C.

[0020] Figure 3 Photothermal heating effect of Nb2C NPs. A. In vitro thermal imaging of Nb2C; B. Photothermal heating curve of Nb2C.

[0021] Figure 4 Shown are the morphological characteristics of the hydrogel patches in each group.

[0022] Figure 5 FTIR spectra of each group of hydrogels.

[0023] Figure 6 Rheological characterization of each group of hydrogels; A. Strain sweep of GH and VNGH; B. Dynamic step strain of GH and VNGH; C. Frequency sweep of GH and VNGH; D. Shear viscosity test of GH and VNGH.

[0024] Figure 7 The photothermal heating effect of Nb2C and various hydrogel solutions. A. In vitro thermal imaging of Nb2C solution (1000 μg / mL) and various hydrogel solutions; B. Photothermal heating curves of Nb2C solution (1000 μg / mL) and various hydrogel solutions.

[0025] Figure 8 This is the drug release curve of VNGH.

[0026] Figure 9 Cell survival rate of NIH-3T3 cells after treatment with different concentrations of VP for 24 h.

[0027] Figure 10 Figure 3 shows the in vitro healing ability of each hydrogel group. A. Cell migration of NIH-3T3 cells treated with the hydrogel extracts (5 μg / mL) for 0, 24, and 48 hours. B. Quantitative statistical analysis after 24 hours of treatment, ∗P < 0.05, ∗∗P < 0.01.

[0028] Figure 11 is the in vitro antibacterial ability of each group of hydrogels (filter paper diameter: 6 mm).

[0029] Figure 12 Schematic diagram of the grouping of wound treatment methods for diabetic mice.

[0030] Figure 13 Representative gross images (A) and wound healing patterns (B) of diabetic mice wounds under different treatments at days 0, 3, 7, 11, and 14; the inner diameter of the white circle in the figure is 15 mm, and the scale bar is 5 mm.

[0031] Figure 14 Semi-quantitative analysis of wounds in diabetic mice treated with different treatments. A. Changes in residual wound area; B. Wound healing rate (n = 5; ∗∗∗∗P < 0.0001; ns, not statistically significant).

[0032] Figure 15 Photothermal effect of hydrogel on the wound surface of diabetic mice. A. Infrared thermal imaging; B. Local temperature rise curve of hydrogel.

[0033] Figure 16 Representative HE staining results on the 14th day after wound modeling in diabetic mice: (A) important organs; (B) wound tissue.

[0034] Figure 17 These are representative results of Masson staining of wound tissue in diabetic mice on the 14th day after wound modeling. DETAILED DESCRIPTION

[0035] The following will be combined with specific implementation methods and examples to specifically describe embodiments of the present invention, and the advantages and various effects of the embodiments of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementation methods and examples are used to illustrate embodiments of the present invention, rather than to limit the embodiments of the present invention.

[0036] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the embodiments of the present invention belong. In the event of any conflict, the present specification shall take precedence.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the embodiments of the present invention can be purchased on the market or obtained through existing methods.

[0038] In order to solve the above technical problems, the overall idea of ​​the present invention is as follows: We successfully synthesized Nb2C NPs with uniform particle size, good photothermal stability, and uniform and stable dispersion in the medium. Through 3D printing performance testing, it was determined that the GelMA concentration was 10%, GelMA:HAMA = 400:1 is the basic mixed hydrogel. Through infrared, ultraviolet, thermogravimetric and other tests, it was confirmed that the composition and structure of VNGH hydrogel are stable and have good thermal stability. The rheological test results show that VNGH has good self-healing, adhesion and injectability. The feasibility of the hydrogel patch as a diabetic wound dressing was tested through swelling, water retention and degradation properties tests. Through photothermal performance characterization, it was determined that the optimal experimental conditions are a wavelength of 808 nm and a power of 1.0 W / cm 2 A hydrogel patch containing 1000 μg / mL of Nb2C NPs was irradiated with a near-infrared laser for 3 minutes. The drug release curve demonstrated that the hydrogel system can achieve sustained release of VP. Furthermore, the hydrogel patch's in vitro biocompatibility, healing-promoting ability, and antibacterial properties were also verified. In summary, we successfully fabricated a composite hydrogel scaffold patch (VNGH) loaded with VP and exhibiting excellent photothermal antibacterial properties.

[0039] In vivo experiments, HE staining of key organs in mice, including the heart, liver, spleen, lungs, and kidneys, demonstrated the hydrogel's reliable biosafety. Animal experiments demonstrated that VNGH effectively promoted wound healing in diabetic mice. Its excellent photothermal antibacterial properties, stimulated by an 808 nm laser, effectively promoted re-epithelialization, granulation tissue regeneration, and the appearance and formation of skin appendages (hair follicles and sebaceous glands) in diabetic wounds, achieving rapid recovery of wound structure and function.

[0040] The following is a detailed description of a photothermal composite hydrogel patch of the present application in combination with examples and experimental data.

[0041] Example 1. Synthesis of Photothermal Composite Hydrogel Patch 1. Preparation of Nb2C NPs 1) Immerse 1g of Nb2AlC powder in 6ml of 50% hydrofluoric acid (HF) aqueous solution to etch away the Al layer. After 2 days, the dispersion is collected by centrifugation and then washed with deionized water. Repeated centrifugation and washing yield the etched Nb2C precipitate. 2) The Nb2C precipitate was ultrasonically dispersed in 6 ml of TPAOH and stirred for 3 days. The Nb2C particle size was further reduced by exfoliation. After repeated washing and resuspending in deionized water, the particles were centrifuged to obtain well-dispersed Nb2C nanoparticles. The Nb2C nanoparticles were re-ultrasonicated in deionized water to obtain Nb2C solutions with concentrations of 500, 1000, and 1500 μg / mL.

[0042] 2. Characterization of Nb2C NPs 1) Morphological characteristics: (1) Transmission electron microscopy: The washed and centrifuged Nb2C precipitate was ultrasonically dispersed in deionized water, and the suspension was dropped onto a transmission electron microscope (TEM) support film. After the droplet was completely dry, the morphology was observed using a transmission electron microscope.

[0043] (2) Scanning electron microscopy: The washed and centrifuged Nb2C precipitate was ultrasonically dispersed in deionized water, and the suspension was dropped onto the scanning electron microscope sample stage. After the droplet was completely dry, the surface was sprayed with gold to observe and collect the surface morphology of Nb2C NPs.

[0044] (3) Atomic force microscopy: Install the probe, add the prepared Nb2C suspension to the sample holder, adjust the position of the probe and sample, bring the microscope lens close to the sample, focus on the sample surface, and collect and characterize the three-dimensional surface morphology of Nb2C NPs.

[0045] TEM and SEM images are shown in Figure 2. Figure 1 Figures A and B show that Nb2C NPs are dispersed particles with uniform size and a long diameter of about 200 nm. Figure 1 (C) Detection of the prepared nanomaterial Nb2C NPs. The EDS element mapping image shows that niobium (red), carbon (yellow), and oxygen (green) are evenly distributed in the Nb2C NPs. The niobium content is approximately twice that of carbon, which is consistent with the element ratio of our target product Nb2C, indicating that we have successfully prepared Nb2C.

[0046] 2) Component Analysis: (1) EDS energy spectrum analysis: Place the sample on a scanning electron microscope. After preliminary observation, select the area of ​​interest for energy spectrum scanning to obtain an element mapping image.

[0047] (2) X-ray diffraction pattern: Use an X-ray diffractometer to determine the crystal structure, size and crystallization characteristics of the sample.

[0048] X-ray diffraction patterns such as Figure 2 As shown in the figure, the main diffraction peaks of the prepared Nb2C appear at positions of approximately 34.4°, 40.2°, 58.4°, and 69.8° at 2θ, corresponding to the (111), (200), (220), and (311) crystal planes, respectively. The sharp shape of the diffraction peaks indicates that the crystal structure of the sample tested is regular and has a high degree of crystallinity. The intensity of these peaks and the corresponding crystal plane positions indicate that the Nb2C phase exists in the sample and the particle crystal structure is relatively complete. The surface characteristics and average particle size of the Nb2C particles were further evaluated using a nanoparticle size and Zeta potential analyzer. When the Zeta potential peak is less than -30 mV or greater than 30 mV, it indicates that there is sufficient electrostatic repulsion between the test particles so that they can remain dispersed in the medium.

[0049] like Figure 2 As shown in Figure B, the Zeta potential peak of Nb2C appears near -25 mV, and the peak is sharp, indicating that the potential distribution of Nb2C particles is relatively concentrated, and the test sample has good uniformity and can maintain a relatively stable dispersion state in the solution system. Figure 2 Figure (C) shows a particle size distribution concentrated between 200 and 300 nm, with an average particle size of 261.5 nm. This is consistent with the line scan results from atomic force microscopy. These results demonstrate that the synthesized Nb2C particles are uniform in size and can be stably and evenly dispersed in the medium, making them suitable for subsequent hydrogel preparation.

[0050] (3) Photothermal properties of Nb2C We selected Nb2C suspensions with concentrations of 500, 1000, and 1500 μg / mL and used a handheld thermal imager to take in vitro thermal imaging images ( Figure 3 Figure A) shows the temperature data collected and plotted for Nb2C at a wavelength of 808 nm and a power of 1.0 W / cm 2 The photothermal temperature rise curves under near-infrared laser irradiation of 808 nm are shown in Figure 3B. Analysis shows that under 808 nm near-infrared light irradiation, the temperatures of 500, 1000, and 1500 μg / mL Nb2C suspensions all rapidly increased in temperature after about 3 minutes and then stabilized, reaching 39.2, 44.6, and 54.4 °C, respectively, after 5 minutes of irradiation. As the irradiation time increases, the temperature of Nb2C of different concentrations gradually increases, and the temperature rise tends to stabilize after 3 minutes. Under the same irradiation time, the higher the Nb2C concentration, the higher the peak temperature. This shows that the photothermal effect of Nb2C is concentration-dependent and irradiation time-dependent.

[0051] The photothermal stability of Nb2C dispersion with a concentration of 1000 μg / mL was further investigated using a power of 1.0 W / cm 2 , after 5 minutes of near-infrared laser irradiation with a wavelength of 808 nm, the near-infrared light was turned off, and the temperature of the Nb2C dispersion was allowed to drop to room temperature. The start of laser irradiation was taken as the zero point, and the dispersion temperature was recorded every 30 seconds. This was repeated for 4 cycles. Results After 5 minutes of near-infrared laser irradiation, the temperature of the 1000 μg / mL Nb2C dispersion rapidly increased from about 22°C at room temperature to 45-48°C, and naturally cooled to room temperature after 10 minutes. In the 4 consecutive cycles of illumination-light-off, the Nb2C dispersion showed regular heating and cooling, and the amplitude and trend of the temperature change remained consistent, indicating that the 1000 μg / mL Nb2C dispersion had good stability and repeatability in the repeated photothermal process, and could be used at a power of 1.0 W / cm 2 The performance of the nanostructured Nb2C NPs remained stable during multiple irradiations with a near-infrared laser at a wavelength of 808 nm, providing an experimental basis for subsequent photothermal therapy. A concentration of 1000 μg / mL of Nb2C NPs was selected for subsequent hydrogel preparation experiments.

[0052] 2. Preparation and Printing of Hydrogel Mixture Solutions 1) Preparation of basic solution: (1) LAP standard solution: Dissolve 50 mg of LAP powder in 10 mL of PBS solution, shake thoroughly, and dissolve evenly to obtain a LAP standard solution with a concentration of 0.5% (W / V).

[0053] (2) HAMA solution: Dissolve 25 mg of HAMA in 1 mL of 0.5% (W / V) LAP standard solution to obtain a 2.5% (W / V) HAMA solution.

[0054] (3) VP solution: Dissolve 10 mg of VP powder in 0.5 mL of DMSO solution, shake thoroughly, and mix evenly to obtain a 2% (W / V) VP solution.

[0055] (4) Nb2C solution: 100 mg of the previously prepared Nb2C powder was ultrasonically mixed in 1 mL of deionized water to obtain a 10% (W / V) Nb2C solution. This Nb2C solution is a solution loaded with niobium carbide nanoparticles (Nb2CNPs).

[0056] (5) VP-Nb2C-GelMA-HAMA (VNGH) mixed solution: 100, 160, 200, and 300 mg of GelMA were dissolved in 1.91 mL of 0.5% (W / V) LAP standard solution, and then 20 μL of 2.5% (W / V) HAMA solution, 20 μL of 10% (W / V) Nb2C solution, and 50 μL of 2% (W / V) VP solution were added. The mixture was thoroughly mixed and filtered using a 0.22 μm filter to obtain VNGH mixed solutions with GelMA concentrations of 5%, 8%, 10%, and 15% (W / V).

[0057] 2) 3D printing: (1) Preparation before printing: Heat the prepared VNGH mixed solution in a 37°C constant temperature water bath for 6 h, then refrigerate it in a 4°C refrigerator for 10 min. Then, add the prepared mixed hydrogel solutions of each group into the sample loading cylinder of the extrusion bio-3D printer and prepare for printing. Keep away from light throughout the process.

[0058] (2) Printing parameter settings: layer height 0.2 mm, trace width 0.4 mm, fill density 40%, printing a grid-shaped cylindrical hydrogel patch with a diameter of 8 mm. After printing, the hydrogel patch was irradiated with a 405 nm handheld light curing light for 210 s to complete the hydrogel photocuring.

[0059] Comparative Example 1: GelMA-HAMA (GH) hydrogel patch GelMA-HAMA (GH) mixed solution: Dissolve 100 mg and 200 mg of GelMA, respectively, in 1.98 mL of 0.5% (w / v) LAP standard solution. Add 20 μL of 2.5% (w / v) HAMA solution, mix thoroughly, and filter the solution through a 0.22 μm filter to obtain GH mixed solutions with GelMA concentrations of 5% and 10% (w / v). 3D printing procedures were the same as in Example 1 to obtain GelMA-HAMA (GH) hydrogel patches.

[0060] Comparative Example 2: Nb2C-GelMA-HAMA (NGH) hydrogel patch Nb2C-GelMA-HAMA (NGH) mixed solution: Add 20 μL of a 10% (w / v) Nb2C solution to 1.98 mL of a 10% (w / v) GelMA-HAMA mixed solution. Mix thoroughly and filter the solution through a 0.22 μm filter to obtain the NGH mixed solution. 3D printing procedures were the same as in Example 1 to obtain a Nb2C-GelMA-HAMA (NGH) hydrogel patch.

[0061] Comparative Example 3: VP-GelMA-HAMA (VGH) hydrogel patch VP-GelMA-HAMA (VGH) mixed solution: Add 50 μL of a 2% (w / v) VP solution to 1.95 mL of a 10% (w / v) GelMA-GH mixed solution. Mix thoroughly and filter the solution through a 0.22 μm filter to obtain a VGH mixed solution. 3D printing procedures were the same as in Example 1 to obtain a VP-GelMA-HAMA (VGH) hydrogel patch.

[0062] Experimental Example 1 The preparation of each group of hydrogel mixed solutions in Example 1 and Comparative Examples 1-3 is shown in Table 1, and the performance of each group was tested.

[0063] Table 1 Preparation of hydrogel mixed solutions in each group

[0064] 1. Morphological observation of hydrogel patches in each group Each hydrogel mixture was 3D-printed into a cylindrical patch with a diameter of 8 mm and a thickness of 2 mm. The GH group was transparent. Compared to the GH group, the NGH group exhibited a white appearance due to the incorporation of 1000 μg / mL of Nb2C NPs. The VGH and VNGH groups, due to the incorporation of VP, exhibited a black appearance similar to VP powder. The hydrogel patches were freeze-dried for 48 hours, gold-sprayed on the surface, and then placed on a scanning electron microscope stage for morphological observation ( Figure 4 The hydrogel patches in each group exhibited an orderly grid-like arrangement, with uniform pore size and a uniform network scaffold thickness. Nb2C NPs were observed to be evenly distributed throughout the network scaffold in the NGH group. The Nb2C NPs in the VNGH group formed a ring-like structure and were evenly distributed. This is likely due to the interaction between Nb2C and specific chemical groups in the VP molecule, which tends to form a stable conjugated ring.

[0065] 2. Spectral analysis of each group of hydrogel patches The chemical structures of the printed hydrogel patches were further examined by FTIR spectroscopy (Figure 5). It can be seen that the GH and NGH groups have no obvious absorption peaks, while the FTIR spectral curves of the VGH and VNGH groups are relatively consistent, with the main absorption peaks appearing at 3281, 3060, 1630, and 1013 cm -1 Of which 3281cm -1 The absorption peak at 3060 cm is usually associated with the stretching vibration of the NH bond, indicating that there may be an amide bond (-CONH) or an amino group (=NH) in VGH and VNGH; -1The absorption peak at 1630 cm is usually associated with the stretching vibration of the C-H bond, indicating that there may be a carboxyl group (-COOH) in VGH and VNGH; -1 The absorption peak at 1013 cm is usually associated with the stretching vibration of the C=C double bond, indicating that there may be unsaturated bonds in VGH and VNGH; -1 The absorption peak at 100 nm is typically associated with stretching vibrations of the C-O-C bond, suggesting the presence of ether bonds in VGH and VNGH. The chemical structure of VP, a benzoporphyrin derivative, reveals a core porphyrin ring (containing two -NH- groups) with characteristic chemical groups including vinyl (-CH=CH-), methoxycarbonyl (-O-CO-CH3), and propionate (-COO-). The characteristic chemical groups detected by FTIR spectra of VGH and VNGH are consistent with the chemical structure of VP, indicating the presence of VP in the synthesized hydrogel system.

[0066] 3. Rheological properties of GH and VNGH Strain sweep results ( Figure 6 A) Shows the elastic and viscous behavior of GH and VNGH under different strain conditions. Within the low strain range (0-10%) and medium strain range (10-100%), the G' values ​​of GH and VNGH are greater than their G'' values, indicating that the elastic characteristics of the hydrogels are greater than their viscous characteristics and that they can recover to their original shape after being subjected to stress. In the high strain range (100-1000%), the G' and G'' values ​​drop sharply, with the decrease in G' greater than that in G''. This indicates that GH and VNGH undergo significant structural failure at high strains, with viscous properties becoming dominant and the hydrogels exhibiting viscous flow behavior or plasticity.

[0067] The intersection of the G' and G'' curves represents the critical point at which the hydrogel material transitions from elasticity-dominated to viscosity-dominated, commonly referred to as the "flow point." The G' and G'' curves for the GH group intersect at a stress of approximately 120%, while those for the VNGH group intersect at a stress of approximately 180%. Furthermore, the downward trend in the G' and G'' curves after the flow point for the VNGH group is significantly less than that for the GH group, indicating that the addition of Nb2C NPs and VP improves the structural stability of the hydrogel.

[0068] Based on the strain sweep results, we chose to switch the strain between 1% and 400%, maintaining each strain level for 60 s to test the dynamic step strain of GH and VNGH. In the strain sweep test, when the strain is 1%, both materials are dominated by elasticity, and when the strain is 400% (3 times the flow point), both materials are dominated by viscosity. Similarly, Figure 6As shown in Figure B, at a strain of 1%, the G' values ​​of GH and VNGH are both stably higher than the G'' values, demonstrating elastic properties. When the strain rises to 400%, the G' values ​​of GH and VNGH drop rapidly, while the G'' values ​​rise rapidly and exceed the G' value, demonstrating viscous properties and network structure destruction. When the strain returns to 1%, the G' values ​​of GH and VNGH increase sharply again and instantly exceed the G'' value, indicating that both have returned to the hydrogel network structure state. Notably, after three cycles of alternating 1% and 400% strain, the G' and G'' values ​​of GH and VNGH can quickly return to their initial values, demonstrating that the addition of Nb2C NPs and VP does not affect the outstanding self-healing ability of the hydrogel.

[0069] Further comparison of the stability of GH and VNGH under different frequency sweeps ( Figure 6 (C) Both exhibit good stability between 0.1 and 10 Hz, with G' values ​​greater than G'', indicating complete gelation and structural stability. The G'' value of the GH group exhibits a partial shift in the high-frequency range, indicating that the GH hydrogel structure is less stable than the VNGH hydrogel at high frequencies.

[0070] During the bio-3D printing process, the hydrogel material needs to maintain a low viscosity at a high shear rate when passing through the printing nozzle to ensure smooth flow, and maintain a high viscosity at a low shear rate after being extruded onto the carrier plane to maintain structural stability.

[0071] Figure 6 Figure D shows the viscosity changes of GH and VNGH at different shear rates. VNGH and GH exhibit similar shear thinning behavior, with the viscosity gradually decreasing as the shear rate increases. GH at a shear rate of 5.5 s -1 The viscosity drop increased dramatically when the shear stress reached the yield stress of GH, causing the hydrogel structure to change and begin to flow. The shear viscosity test results show that GH and VNGH have excellent injectability and also prove that VNGH has better structural stability than GH.

[0072] The above experimental results show that the dual matrix ratio (GelMA 10% + HAMA 0.025%) makes VNGH have: (1) high structural stability (flow point 180%, G' recovery >95% after strain 400%), Figure 6 (2) Excellent injectability (shear thinning index n=0.35), meeting the requirements of 3D printing.

[0073] 4. Characterization of photothermal properties of each group of hydrogel solutions After verifying the photothermal effect of Nb2C, we used 1000μg / mL Nb2C NPs solution as a control to test the photothermal performance of GH, NGH, VGH, and VNGH solutions. A handheld thermal imager was used to capture in vitro thermal imaging images ( Figure 7 (A) Temperature data were collected and plotted at a wavelength of 808 nm and a power of 1.0 W / cm 2 The photothermal temperature rise curves of each group of solutions under near-infrared laser irradiation. Figure 7 Figure B shows that under 808 nm near-infrared light irradiation, the temperatures of 1000 μg / mL Nb2C NPs, NGH, and VNGH solutions all rapidly increased after approximately 3 minutes before stabilizing, reaching average temperatures of 41.6, 46.2, and 58.9°C, respectively, at 3 minutes. After 5 minutes, they reached 44.6, 48.6, and 65.5°C, respectively. The temperatures of the Nb2C NPs, NGH, and VNGH solutions gradually increased with irradiation time. The temperature increases of the Nb2C NPs and VNGH solutions stabilized after 3 minutes, while the NGH solution reached a nearly constant temperature after 2 minutes. The temperature increase of the VNGH solution after 3 minutes was the most significant of the three, at approximately 4°C / min. At the same irradiation time, the VNGH solution maintained a higher temperature than the NGH solution and the Nb2C NPs solution. The NGH hydrogel solution reached the final stable temperature earlier than the Nb2C NPs deionized water solution, and the final temperature was higher than that of the Nb2C NPs solution. This may be because the distribution of Nb2C NPs in the GH mixed hydrogel system is more uniform and stable, thereby improving the photothermal conversion efficiency. The VNGH solution has the largest temperature rise and the highest final temperature among the three. This is considered to be because the hydrogel turned black after the addition of VP, and the Nb2C particles formed a ring structure after the addition of VP to the hydrogel under the scanning electron microscope, which improved the light absorption efficiency and photothermal conversion efficiency of the VNGH hydrogel. In order to achieve the photothermal antibacterial effect and maintain it within a safe temperature range so as not to cause thermal damage to normal cells and healthy tissues, a wavelength of 808 nm and a power of 1.0 W / cm were selected in subsequent animal experiments. 2 The near-infrared laser was irradiated for 3 min.

[0074] 5. Drug release characteristics of VNGH hydrogel patch During the hydrogel patch production process, VP molecules are evenly wrapped in the pores of the GH hydrogel's three-dimensional network structure. As the hydrogel absorbs liquid and swells, the pores gradually increase, and it gradually degrades over time, the drug molecules inside are continuously released during the process. In order to clarify the drug release characteristics of VP in the VNGH hydrogel patch, we placed the VNGH hydrogel patch in a PBS solution and incubated it together. At set time intervals, we drew a quantitative solution and used a spectrophotometer to detect the VP concentration of the solution at 689 nm. The VP release curve was drawn based on the measured VP concentration and the set time ( Figure 8 ).

[0075] like Figure 8 As shown in the figure, approximately 55% of VP was released into the PBS solution within 48 hours, and approximately 88% of VP was released after 288 hours, demonstrating that the hydrogel system can achieve sustained release of VP. The VP release rate increased significantly after 192 hours, likely due to hydrogel degradation. The sustained and sustained release of VP can help reduce the need for frequent drug administration and extend the duration of drug action after a single dose, thereby improving the convenience of diabetic wound treatment and patient compliance.

[0076] 6. Biocompatibility of each group of hydrogel patches VP was first used in ophthalmology to treat age-related macular degeneration. In recent years, it has begun to be used in various tumor diseases, including leukemia, breast cancer, and neuroblastoma. High concentrations of VP can inhibit tumor cell proliferation and migration, so it is necessary to evaluate the safety of VP in subsequent experimental use. The VP solution was mixed with prepared complete cell culture medium to obtain cell culture medium with a VP concentration of 1 to 10 μg / mL. NIH-3T3 cells were cultured in cell culture medium containing varying concentrations of VP, using complete cell culture medium (0 μg / mL) as a control. After 24 hours of treatment, CCK8 reagent was added proportionally. The OD value of the supernatant was measured at 450 nm, and cell viability was calculated.

[0077] Figure 9 Studies have shown that when VP concentrations do not exceed 5 μg / mL, the survival rate of NIH-3T3 cells is not significantly different from that of the control group. However, when VP concentrations are 6 μg / mL or higher, the survival rate of NIH-3T3 cells is inversely proportional to the VP concentration. After 24 hours of treatment with VP at a concentration of 8 μg / mL, the survival rate of NIH-3T3 cells is only 75.8%. Therefore, if VP solution is applied directly to the wound surface, the dosage concentration must be strictly controlled to ensure safety for normal cells.

[0078] In order to verify and explore the safe concentration range for subsequent cell experiments, we immersed each group of hydrogels in complete cell culture medium and shook them in a shaker at 37°C and 200 rpm for 24 hours to obtain the corresponding hydrogel extracts, which were then diluted into extracts with different concentration gradients for CCK8 detection.

[0079] At a 5 μg / mL extract concentration, cell viability remained above 91% after 24 hours of treatment with the hydrogel extract in all groups. At a 10 μg / mL extract concentration, cell viability in the VGH and VNGH groups dropped below 70%, and at a 20 μg / mL extract concentration, cell viability in the NGH group dropped below 70%. Based on the results of the CCK8 assay, a 5 μg / mL hydrogel extract was selected for subsequent experiments. NIH-3T3 cells were treated with the 5 μg / mL hydrogel extracts for 0, 24, 48, and 72 hours, and cell viability was measured at the corresponding time points. No significant differences in cell viability were observed between the hydrogel groups and the control group, and cell viability remained above 93%, confirming the good cell safety of the prepared hydrogels.

[0080] 7. In vitro healing ability of each group of hydrogel patches The high-glucose environment of diabetes can affect local cell viability and migration ability in wounds, thereby delaying wound healing. We used serum-free, high-glucose cell culture medium to perform a scratch test to test the ability of the hydrogel patch to promote wound healing in vitro. Direct microscopic observation showed that at 24 hours, there was no significant difference in cell migration rate between the GH and NGH groups and the control group, while the cell migration rate in the VGH and VNGH groups was higher than that in the control group ( Figure 10 (A). According to Figure 10 Figure B shows that the 24-hour migration rate was approximately 5.03% in the VGH group, 4.80% in the VNGH group, and 3.08% in the control group. Microscopically, the scratches in the VNGH group were nearly completely closed at 48 hours, and cell migration and proliferation were significantly superior to those in the other groups, demonstrating that the VNGH hydrogel patch has excellent in vitro healing properties.

[0081] 8. In vitro antibacterial ability of each group of hydrogel patches Previous studies have reported that Nb2C, in addition to producing a photothermal effect to ablate bacteria under 808 nm laser irradiation, can also inhibit bacterial energy metabolism, thereby disrupting biofilm formation and directly eliminating bacteria. VP's ability to disrupt bacterial structure is dose-dependent, with its antibacterial ability being evident at concentrations exceeding 4 μg / mL. Under 689 nm laser irradiation, VP can be activated to produce singlet oxygen and ROS, killing bacteria, and the antibacterial effect is enhanced by light activation. To verify the in vitro antibacterial efficacy of the hydrogel patch, we used an inhibition zone assay to test the inhibitory effects of each hydrogel group on S. aureus (representing Gram-positive bacteria) and E. coli (representing Gram-negative bacteria).

[0082] Blank sterilized drug-sensitive paper strips were soaked in a 5 μg / mL dilution of each hydrogel extract, using cell culture medium without penicillin-streptomycin solution as a control. After soaking for 24 hours, each filter paper strip was placed in a 37°C oven until completely dried. The dried filter paper strips were then placed on a plate inoculated with bacteria and incubated at 37°C for 24 hours. The formation of a transparent zone of inhibition around the filter paper strips was observed. The diameter of the zone of inhibition directly reflects the degree of bacterial inhibition by the hydrogel extract. A larger zone of inhibition indicates that the corresponding hydrogel can effectively inhibit the proliferation and spread of bacteria and has strong antibacterial properties.

[0083] Figure 11 It can be seen that NGH, VGH, and VNGH all have some antibacterial effect against E. coli and S. aureus, with the diameter of the inhibition zone for S. aureus being significantly larger than that for E. coli. Nb2C and VP have strong antibacterial effects against the Gram-positive S. aureus, but weaker antibacterial effects against Gram-negative E. coli, possibly due to the hydrophobic lipopolysaccharide components of the Gram-negative bacterial outer membrane acting as a drug barrier. In the absence of laser irradiation, Nb2C has a stronger antibacterial effect than VP (NGH vs. VGH). The combination of the two (VNGH) exhibits a synergistic effect against Gram-negative bacteria, achieving a more pronounced antibacterial effect than either NGH or VGH alone.

[0084] Experimental Example 2: VNGH hydrogel patch promotes wound healing in diabetic mice 1. Construction and grouping of diabetic mouse models 1. Modeling steps: (1) Prepare a 1% (W / V) mixed solution of STZ and sodium citrate (i.e., dissolve 0.1 g of STZ in 10 mL of sodium citrate buffer) in a dark environment and use it within 15 minutes.

[0085] (2) Intraperitoneal injection of 150 mg / kg STZ was performed on mice. A 20 g mouse was intraperitoneally injected with 0.3 mL of 1% (W / V) STZ sodium citrate mixed solution.

[0086] (3) After STZ injection, the bedding was changed and sufficient water was ensured. One week later, the fasting blood glucose level was measured by tail-cutting method. Thereafter, random blood glucose was measured every 7 days. After one month of observation, if the fasting blood glucose level was >11.1 mmol / L and the random blood glucose level was >16.7 mmol / L for three consecutive times, the diabetic model of mice was considered to be successfully established and the wound modeling experiment could be carried out.

[0087] 2. Blood glucose was measured in 50 C57BL male mice one week after intraperitoneal injection of STZ. Fasting blood glucose values ​​of 47 mice were >11.1 mmol / L. Random blood glucose was measured every 7 days thereafter. After one month of observation, 5 mice died and 45 mice survived. Among the surviving mice, random blood glucose values ​​of 40 mice were >16.7 mmol / L for three consecutive times, and random blood glucose values ​​of 5 mice were <16.7 mmol / L. Therefore, these 40 successfully established diabetic mouse models were finally selected for the next step of wound modeling.

[0088] Overall, compared with the pre-modeling period, the successfully established diabetic mice showed typical diabetic symptoms such as gradual weight loss, coarse and easily falling hair, lethargy, polydipsia, polyphagia, and polyuria. We established a full-thickness skin defect diabetic mouse model by artificially creating a circular skin incision with a diameter of 1 cm on the back of the diabetic mice. These 40 mice were randomly divided into 5 groups and treated with different treatments using a power of 1 W / cm 2 The effects of irradiation with 808 nm near-infrared light for 3 minutes on diabetic wound healing were compared. The groups were sterile PBS treatment group (hereinafter referred to as the PBS group), GH patch treatment group (hereinafter referred to as the GH group), NGH patch treatment group (hereinafter referred to as the NGH group), VGH patch treatment group (hereinafter referred to as the VGH group), and VNGH patch treatment group (hereinafter referred to as the VNGH group).

[0089] 2. Wound healing in diabetic mice We photographed the wound healing of diabetic mice in each group on the day of wound modeling and on days 3, 7, 11, and 14 after modeling. The skin wound area and healing process of each group are shown in the figure. Figure 13) showed that the wound area of ​​each diabetic mouse group gradually decreased over time. Because mice have a certain degree of wound healing ability, the wounds of the mice in the PBS, GH, and NGH groups did repair to some extent, even without the effect of VP. However, the VGH and VNGH groups showed faster wound healing. Furthermore, the epidermis was visible in the healed areas of the PBS, GH, and NGH groups, while the epidermis of the VGH and VNGH groups was almost completely covered with hair at the same time point. Figure 13 Figure B is a schematic diagram of overlapping wound surface areas at different time intervals. The results showed that the degree of wound repair increased in a time-dependent manner, and the wound healing efficiency of the VNGH and VGH groups was the highest. Figure 13 The wound healing rate is consistent with that in Figure A. From the overall picture, we can conclude that the hydrogel patch containing VP can promote faster healing of diabetic wounds and accelerate hair growth after wound healing.

[0090] 3. Analysis of wound healing results in diabetic mice After five different treatments were applied to the wounds of diabetic mice, semi-quantitative analysis (Figure 14) showed that the wounds of mice treated with VNGH had healed to over 70% by day 3 and were nearly completely healed (95%) by day 11, while the wounds of the PBS and GH groups healed more slowly. Furthermore, the NGH group initially healed faster than the PBS and GH groups, but at day 14, no significant difference in healing was observed between the NGH, GH, and PBS groups. This demonstrates that the photothermal effect of Nb2C NPs plays a role in the initial healing of wounds but is not a key factor significantly affecting the final healing efficiency of diabetic wounds. Furthermore, while the final healing efficiency of the VNGH and VGH groups was not significantly different, the VNGH group significantly outperformed the VGH group at day 7, likely due to the photothermal antibacterial and antioxidant properties of Nb2C NPs. This also indirectly reflects the unique advantages of the dual-loaded Nb2C NPs and VP hydrogel system.

[0091] 4. Photothermal effect of hydrogel in vivo We used a wavelength of 808 nm and a power of 1.0 W / cm 2 The near-infrared laser was directed at the hydrogel patch placed on the wound to irradiate the wound for 3 minutes. Figure 15As shown, the final local temperature of the wound surface in the VNGH group was the highest among all groups, reaching 52.5°C. At 30 seconds, the temperatures in the VNGH and NGH groups reached 41.9°C and 40.5°C, respectively. It took 2 minutes for the local temperature in the VNGH group to reach 50°C. These experimental results demonstrate that the photothermal effect of Nb2C NPs in the hydrogel can be effectively stimulated under these illumination conditions, achieving an antibacterial effect while avoiding high-temperature burns to the skin tissue and coagulative necrosis of the surrounding tissue.

[0092] 5. Biosafety of Hydrogels and Their Ability to Promote Wound Healing The biosafety of the hydrogel has been confirmed at the cellular level. To further confirm the biosafety of the hydrogel patch in direct contact with the wound, we collected samples from diabetic mice, including the heart, liver, spleen, lungs, and kidneys, and fixed them on paraffin sections 14 days after wound initiation. These samples were then stained with hematoxylin and eosin.

[0093] Figure 16 Results in Figure A show that HE staining of key organs in the PBS, GH, NGH, VGH, and VNGH groups showed no obvious signs of damage or inflammation, and no significant differences were observed between groups. Therefore, we preliminarily conclude that the VNGH hydrogel patch has good biosafety and lacks potential toxicity, meeting the basic requirements for future wound treatment applications.

[0094] In diabetic mice, the wound tissue of the VNGH group has completely achieved epithelialization, with intact epidermal structure, tightly arranged keratinocytes, orderly arranged collagen fibers in the dermis, no obvious inflammatory cell infiltration, and intact and evenly distributed skin appendages such as hair follicles and sebaceous glands. There is no significant difference between the tissue structure of the healing part and the normal tissue structure at the edge ( Figure 16 (B) Compared to the PBS group, both the NGH and VGH groups showed improved wound epithelialization. However, the NGH group had not yet developed skin appendages, and the VGH group had not yet fully regenerated skin appendages. In the PBS and GH groups, the epidermis was not fully regenerated, with incomplete granulation tissue maturation, disorganized collagen, and abundant inflammatory cells. Residual scabs were still visible on the epidermis in the PBS group. Therefore, in the VNGH group, the newly formed epidermis completely covered the wound, with no significant difference in epidermal thickness compared to the surrounding normal tissue. Granulation tissue gradually matured, with fewer fibroblasts and a significant decrease in inflammatory cells. Skin appendages regenerated well, resulting in a more significant repair effect than in the other groups. This suggests that the VNGH hydrogel patch has a superior ability to promote wound epidermal regeneration and tissue repair, effectively accelerating the structural and functional repair of the wound surface.

[0095] VI. VNGH hydrogel patch promotes tissue remodeling in diabetic wounds Masson staining uses various dyes to stain different components in the tissue, making the collagen fibers in the wound tissue appear blue, the muscle fibers appear red, and the cell nuclei appear blue-black.

[0096] Figure 17 The results of Masson staining showed that the dermis of the PBS, GH and NGH groups was thinner, the collagen fibers were deposited in disorder, and the number of new capillaries was still large. The inflammatory infiltration in the NGH group was better than that in the PBS and GH groups. The dermis thickness of the VGH group increased, but the development of skin appendages such as hair follicles was not yet mature. The dermis of the VNGH group was significantly thicker than that of the other treatment groups, the collagen fibers were arranged regularly and directionally, the skin appendages such as hair follicles and sebaceous glands were mature, and the new blood vessels gradually degenerated and stabilized. The remodeling process of the healed wound tissue in the VNGH group was basically completed, and the structure was closer to normal skin tissue. The new capillaries that were formed in large numbers in the early stage of wound healing to meet the high demand for oxygen and nutrients by the wound gradually degenerated, and the blood vessel density was basically the same as that of normal skin tissue. For diabetic wounds, the use of VNGH hydrogel patches has higher extracellular matrix reconstruction and tissue remodeling efficiency than other treatment measures.

[0097] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0098] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0099] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if such changes and modifications fall within the scope of the claims of the embodiments of the present invention and their equivalents, the embodiments of the present invention are intended to include such changes and modifications.

Claims

1. A photothermal composite hydrogel patch, characterized in that: The photothermal composite hydrogel patch is: Using methacryloylated gelatin (GelMA) and methacryloylated hyaluronic acid (HAMA) as the matrix, loaded with niobium carbide nanoparticles (Nb2CNPs) and verteporfin (VP), and formed into a three-dimensional grid-like porous structure by 3D printing or casting, referred to as VP-Nb2C@GelMA / HAMA (VNGH) hydrogel patch.

2. The photothermal composite hydrogel patch according to claim 1, characterized in that: The photothermal composite hydrogel patch has a pore size of 150-250 μm and a porosity of 30%-50%.

3. The photothermal composite hydrogel patch according to claim 1, characterized in that: The mass ratio of the GelMA to HAMA is 350-450:

1.

4. A method for preparing the photothermal composite hydrogel patch according to any one of claims 1 to 3, characterized in that: The method comprises: GelMA was dissolved in a solution containing the photoinitiator LAP, and HAMA, Nb2CNPs dispersion, and VP solution were added in sequence, mixed, and filtered. VP-Nb2C@GelMA / HAMA (VNGH) hydrogel patch was obtained by 3D printing or casting molding.

5. The method for preparing a photothermal composite hydrogel patch according to claim 4, characterized in that: The concentration of the GelMA after being dissolved in PBS is 5%-15% (w / v), the concentration of the HAMA after being dissolved in PBS is 0.01%-0.05% (w / v), and the volume ratio of the GelMA to the HAMA is 350-450:

1.

6. The method for preparing a photothermal composite hydrogel patch according to claim 4, characterized in that: The working concentration of Nb2CNPs in the Nb2CNPs dispersion is 500-1500 μg / mL.

7. The method for preparing a photothermal composite hydrogel patch according to claim 4, characterized in that: In the DMSO solution of VP, the working concentration of VP is 3-500 μg / mL.

8. The method for preparing a photothermal composite hydrogel patch according to claim 4, characterized in that: 405 nm light curing is used in the 3D printing.

9. Use of the composite hydrogel patch according to any one of claims 1 to 3 in preparing a dressing for treating diabetic wounds.

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