Photoresponse microneedle system for promoting repair of diabetes infected wound and preparation method of photoresponse microneedle system

Abstract

The invention belongs to the technical field of biomedical materials, and particularly relates to a composite microneedle for diabetes wound repair and application of the composite microneedle. According to the invention, a specific mold design is adopted, and the photocatalytic nanoparticles are accurately loaded on the tip part of the microneedle, so that the photocatalytic function application of the microneedle in the medical or biological field is realized. The preparation method has the advantages of being easy and convenient to operate, high in precision, good in repeatability and the like, and powerful support is provided for further development of the microneedle technology. In the process of promoting healing of diabetic wounds, the photocatalytic nanoparticles reduce the glucose level of the diabetic wounds under irradiation of visible light, generate H2 to eliminate inflammation, relieve oxidative stress and regulate and control polarization of macrophages at the same time, and then promote healing of the wounds. The photocatalytic composite microneedle is expected to become a novel multifunctional biological material for removing biofilms and promoting healing of diabetic wounds, and has a good application prospect in clinical treatment of the diabetic wounds.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, specifically relating to a composite microneedle for the repair of diabetic wounds and its application. Background Technology

[0002] With societal development and rising living standards, the incidence of diabetes is increasing. Treatment typically involves oral or injectable medications to control the various symptoms caused by abnormal blood sugar levels. Consequently, wounds in diabetic patients are more susceptible to pathogenic invasion than those in healthy individuals. Furthermore, the combined effects of hyperglycemia, peripheral neuropathy, microcirculatory disturbances, and inflammation contribute to delayed wound healing in diabetic patients. Biofilm formation is a significant challenge in the treatment of diabetic wound infections. As a protective structure secreted by microorganisms, biofilms possess strong defensive capabilities, resisting attacks from the host immune system and antibiotics. This makes the treatment of diabetic wound infections even more complex and difficult.

[0003] Currently, clinical treatments for diabetic wound infections mainly include blood glucose control, surgical debridement, antibiotic therapy, and the use of antibiofilm agents. However, these methods all have certain limitations. For example, simple antibiotic therapy and surgical debridement often fail to completely remove bacteria that have formed a stable biofilm, leading to recurrent infections; long-term use of antibiotics may lead to bacterial resistance; surgical debridement causes significant pain and trauma to patients, easily causing infection and some complications; while antibiofilm agents can disrupt the biofilm structure, they are still in the clinical trial stage, and their efficacy and safety remain to be verified.

[0004] In recent years, photocatalysis has been widely used in the treatment of biofilm-infected diabetic wounds. By utilizing photocatalysts under visible light irradiation, glucose can be efficiently consumed and hydrogen generated. This process not only facilitates the local consumption of glucose, but the generated hydrogen also has potential therapeutic effects. Local glucose consumption can inhibit the synthesis of advanced glycation end products (AGEs) and the expression of their receptors, thereby reducing skin cell apoptosis and promoting their proliferation and migration. This mechanism helps promote the healing of diabetic wounds. Furthermore, photocatalysis generates a redox effect under light irradiation, which can achieve the removal of biofilms and the killing of bacteria.

[0005] Microneedles can penetrate biofilms, solving the problem of drug penetration into biofilms. Therefore, the development of composite microneedles with photocatalytic function is aimed at removing biofilms and promoting the healing of diabetic wounds, thus playing a therapeutic role in biofilm-infected diabetic wounds. Summary of the Invention

[0006] This invention prepares microneedles for repairing infectious diabetic wounds by casting using a specific mold, while precisely loading photocatalytic nanoparticles onto the tip of the microneedles. This composite microneedle with photocatalytic function can not only remove biofilms from diabetic wounds, but also promote the healing of diabetic wounds by utilizing H2 generated by photocatalysis. This dual-functional biomaterial has excellent application prospects in the fields of removing biofilms and promoting the healing of diabetic wounds.

[0007] In a first aspect, the present invention provides a composite nanoparticle, the preparation method of which includes the following steps: S1. Pt nanoparticles were synthesized using a hot solvent method; S2. Pt@NH2-UiO-66 nanoparticles are obtained by coating the Pt nanoparticles obtained in step 1 with NH2-UiO-66 nanomaterials. S3. The outer layer of the Pt@NH2-UiO-66 nanoparticles obtained in step 2 is deposited with Co3O4 to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles.

[0008] Furthermore, the preparation method includes the following steps: S1. Thoroughly mix chloroplatinic acid hexahydrate and polyvinylpyrrolidone to prepare a precursor solution. Stir the precursor solution magnetically at 180 °C for 10 minutes. Add excess acetone to the solution after reaction and centrifuge at 8000 rpm for 5 minutes to obtain Pt nanoparticles. Dilute the Pt nanoparticle colloidal solution to 1 mg / mL for later use. S2. Zirconium chloride and 2-aminoterephthalic acid were dissolved in DMF and stirred for 5 minutes. Then, acetic acid and Pt nanoparticles prepared in step 1 were added to the mixed solution and stirred for 5 minutes to prepare a precursor solution. Finally, the precursor solution was added to a hydrothermal reactor and reacted for 12 hours. The final product was collected by centrifugation and washed three times with DMF and methanol respectively. After drying, it was annealed at 200 °C for 2 hours under N2 gas protection to obtain Pt@NH2-UiO-66 nanoparticles. S3. Dissolve cobalt nitrate hexahydrate and potassium iodate in deionized water, add 1 mL of 25% ammonia, stir magnetically and heat in a water bath to 60 °C, wash three times with RO water, and dry in an oven to obtain Co3O4 nanoparticles. S4. Dissolve cobalt nitrate hexahydrate in RO water and add it to the reaction system of step 3. After the temperature is raised to 60 ℃, react for 3 h. Collect the final product by centrifugation and wash it three times with RO water. Sonicate the final product multiple times and centrifuge it in a gradient to wash away the free Co3O4 nanoparticles. Dry it in an oven to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles.

[0009] Furthermore, in step 1, the content of added chloroplatinic acid hexahydrate is 25.37 mg, the content of added polyvinylpyrrolidone is 111 mg, and the content of added acetone is greater than the ratio of the solution of 10:1.

[0010] Furthermore, in step 2, the content of added zirconium chloride is 61.2 mg, and the content of added 2-aminoterephthalic acid is 87 mg.

[0011] Furthermore, in step 3, the content of added cobalt nitrate hexahydrate is 72.8 mg, the content of added potassium iodate is 100 mg, and the content of added Pt@NH2-UiO-66 nanoparticles prepared in step 2 is 100 mg.

[0012] Furthermore, in step 4, the content of added cobalt nitrate hexahydrate is 14.6 mg, and the content of RO water is 20 mL.

[0013] Furthermore, the particle size of the composite nanoparticles is 100~130 nm.

[0014] Furthermore, the particle size of the composite nanoparticles is preferably 120 nm.

[0015] In a second aspect, the present invention provides the application of the composite nanoparticles as described in the first aspect in the preparation of pharmaceutical formulations for treating biofilm-infected diabetic wounds and other adjunctive medical products.

[0016] Furthermore, the pharmaceutical preparation further contains other active pharmaceutical ingredients.

[0017] Furthermore, the active pharmaceutical ingredient is selected from one or more of exenatide, benaglutide, liraglutide, dulaglutide, and insulin.

[0018] Furthermore, the dosage form of the pharmaceutical preparation is selected from one or more of the following: sugar-coated tablets, film-coated tablets, enteric-coated tablets, capsules, hard capsules, soft capsules, oral liquids, lozenges, granules, powders, pills, suspensions, powders, tinctures, preparations, drops, injections, powder for injection, creams, sustained-release agents, and targeted agents.

[0019] Furthermore, the other auxiliary medical products are selected from one or more of the following: drug delivery systems, diabetes infection detection kits, combination drug adjuvants, and capsule coating agents.

[0020] Thirdly, the present invention provides a composite microneedle, characterized in that the composite microneedle comprises a needle tip containing composite nanoparticles as described in one aspect and a backing containing an aqueous solution of polyvinyl alcohol.

[0021] Furthermore, the composite microneedle has a base diameter of 200~450 nm, a length of 600~750 nm, and an apex angle of 2°~4°.

[0022] Furthermore, the composite microneedle preferably has a base diameter of 300 nm, a length of 650 nm, and an apex angle of 3°.

[0023] Fourthly, the present invention provides the application of the composite microneedles as described in the third aspect in the preparation of a wound repair drug for treating biofilm-infected diabetic wounds.

[0024] Furthermore, diabetes is a chronic disease characterized by hyperglycemia, caused by an absolute or relative deficiency of insulin secretion and impaired utilization.

[0025] Furthermore, the composite microneedles can penetrate the biological membrane to disperse photocatalytic nanoparticles within it. Under visible light irradiation, the photocatalytic nanoparticles undergo a photocatalytic reaction to oxidize GSH, causing oxidative stress on the biological membrane and thus reducing wound infection.

[0026] Furthermore, the composite microneedles can improve the wound healing rate of the photothermal / photocatalytic group.

[0027] The beneficial effects of this invention are: This invention prepares composite microneedles with photocatalytic function. Under visible light irradiation, the photocatalytic nanoparticles generate a photocatalytic effect, causing oxidative stress on biofilms and reducing glucose levels in diabetic wounds. Simultaneously, they generate H2 for synergistic photothermal sterilization, anti-biofilm action, and wound healing. The photocatalytic nanoparticles oxidize glucose under visible light irradiation, reducing glucose levels in diabetic wounds. At the same time, the photocatalyst reduces H2... + The generated H2 eliminates inflammation, alleviates oxidative stress, regulates macrophage polarization, and promotes wound healing. Ultimately, the combined microneedle photothermal / photocatalytic therapy removes the biofilm, promotes the healing of diabetic wounds, and achieves the cure of biofilm-infected diabetic wounds. Attached Figure Description

[0028] Figure 1 Hydrated particle size distribution of different nanoparticles Figure 2 Scanning electron microscope image of a microneedle patch with Pt@NH2-UiO-66@Co3O4 nanoparticles loaded at the tip. Figure 3 Microneedle SEM images Figure 4 The killing effect of compound microbes on methicillin-resistant Staphylococcus aureus (MRSA); Figure 5The killing effect of composite microbes on MRSA biofilms; Figure 6 Cell compatibility of nanoparticles and microneedles (a: HSF cell live / dead staining image; b: HUVEC cell live / dead staining image; c: HSF cell survival rate; d: HUVEC cell survival rate) Figure 7 Blood compatibility of nanoparticles and microneedles: a) Hemolysis test; b) Coagulation test Figure 8 Polarization of macrophages under different treatment conditions (a: flow cytometry image of M1 macrophages; b: flow cytometry image of M2 macrophages; c: proportion of M1 macrophages; d: proportion of M2 macrophages) Figure 9 Wound healing in mice under different treatment groups Detailed Implementation To facilitate understanding of the present invention, the present invention will be further described in detail below with reference to embodiments.

[0029] It should be noted that, unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods, and the reagents and materials, including Pt@NH2-UiO-66@Co3O4 nanoparticles, can be obtained commercially unless otherwise specified.

[0030] The experimental mice were 6-week-old male Kunming rats, weighing 29-32 g, all purchased from Sichuan Dashuo Biotechnology Co., Ltd. High-sugar, high-fat feed was also purchased from Sichuan Dashuo Biotechnology Co., Ltd.

[0031] Example 1: Preparation of Pt@NH2-UiO-66@Co3O4 composite nanoparticles Step S1: Synthesis of Pt nanoparticles using a hot solvent method: First, 10 mL of ethylene glycol was added to a double-necked round-bottom flask, followed by 25.37 mg of chloroplatinic acid hexahydrate and 111 mg of polyvinylpyrrolidone. The mixture was thoroughly mixed to prepare a precursor solution. The precursor solution was reacted at 180 °C with magnetic stirring for 10 minutes. Excess acetone was added to the reaction solution, and then the mixture was centrifuged at 8000 rpm for 5 minutes to obtain Pt nanoparticles. The Pt nanoparticle colloidal solution was diluted to 1 mg / mL for later use. Step S2: Dissolve 61.2 mg zirconium chloride and 87 mg 2-aminoterephthalic acid in 60 mL DMF and stir for 5 minutes. Then, add 7.2 mL acetic acid and 36 mL Pt nanoparticle colloidal solution to the mixed solution and stir for 5 minutes to prepare the precursor solution. Finally, add the precursor solution to a hydrothermal reactor and react in a sealed container at 120 °C for 12 h. Collect the final product by centrifugation and wash it three times with DMF and methanol respectively. After drying, anneal it at 200 °C for 2 h under N2 gas protection to obtain Pt@NH2-UiO-66 nanoparticles. Step S3: Dissolve 72.8 mg of cobalt nitrate hexahydrate and 100 mg of potassium iodate in 50 mL of RO water, add 1 mL of 25% ammonia water, stir magnetically and heat in a water bath to 60 °C, wash three times with RO water, and dry in an oven to obtain Co3O4 nanoparticles. Step S4: Dissolve 14.6 mg of cobalt nitrate hexahydrate in 20 mL of RO water and add it to the reaction system in step 3. After the temperature is raised to 60 °C, react for 3 h. Collect the final product by centrifugation and wash it three times with RO water. Sonicate the final product multiple times and perform gradient centrifugation to wash away the free Co3O4 nanoparticles. Dry it in an oven to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles.

[0032] Example 2 Characterization of composite nanoparticles DLS is used to detect the particle size and radius distribution in suspensions or polymers in solution samples.

[0033] The results are as follows Figure 1 As shown, the average hydrated particle size of NH2-UiO-66 nanoparticles is approximately 100 nm, while that of Pt@NH2-UiO-66 nanoparticles is approximately 120 nm, slightly larger than that of NH2-UiO-66 nanoparticles. However, the average hydrated particle size of Pt@NH2-UiO-66@Co3O4 (i.e., PUC) nanoparticles reaches 160 nm, greater than that of Pt@NH2-UiO-66 nanoparticles, thus confirming the synthesis of Pt@NH2-UiO-66@Co3O4 (i.e., PUC) nanoparticles.

[0034] Example 3: Preparation method of composite microneedles This embodiment includes the following specific steps: Step S1: Synthesis of Pt nanoparticles using a hot solvent method: First, 10 mL of ethylene glycol was added to a double-necked round-bottom flask, followed by 25.37 mg of chloroplatinic acid hexahydrate and 111 mg of polyvinylpyrrolidone. The mixture was thoroughly mixed to prepare a precursor solution. The precursor solution was reacted at 180 °C with magnetic stirring for 10 minutes. Excess acetone was added to the reaction solution, and then the mixture was centrifuged at 8000 rpm for 5 minutes to obtain Pt nanoparticles. The Pt nanoparticle colloidal solution was diluted to 1 mg / mL for later use. Step S2: Dissolve 61.2 mg zirconium chloride and 87 mg 2-aminoterephthalic acid in 60 mL DMF and stir for 5 minutes. Then, add 7.2 mL acetic acid and 36 mL Pt nanoparticle colloidal solution to the mixed solution and stir for 5 minutes to prepare the precursor solution. Finally, add the precursor solution to a hydrothermal reactor and react in a sealed container at 120 °C for 12 h. Collect the final product by centrifugation and wash it three times with DMF and methanol respectively. After drying, anneal it at 200 °C for 2 h under N2 gas protection to obtain Pt@NH2-UiO-66 nanoparticles. Step S3: Dissolve 72.8 mg of cobalt nitrate hexahydrate and 100 mg of potassium iodate in 50 mL of RO water, add 1 mL of 25% ammonia water, stir magnetically and heat in a water bath to 60 °C, wash three times with RO water, and dry in an oven to obtain Co3O4 nanoparticles. Step S4: Dissolve 14.6 mg of cobalt nitrate hexahydrate in 20 mL of RO water and add it to the reaction system in step 3. After the temperature is raised to 60 °C, react for 3 h. Collect the final product by centrifugation and wash it three times with RO water. Sonicate the final product multiple times and centrifuge it in a gradient to wash away the free Co3O4 nanoparticles. Dry it in an oven to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles. Step S5: Take 300 mg of Pt@NH2-UiO-66@Co3O4 nanoparticles and add them to 1 mL of 15 w% PVA aqueous solution and stir evenly to use as microneedle tip material. Take an appropriate amount of microneedle tip material and drop it into a PDMS microneedle mold. Place it in a vacuum drying oven under negative pressure (vacuum degree: 0.09 MPa) for 15 min. Step S6: Dissolve polyvinyl alcohol (PVA) in RO water to prepare a 15 w% PVA aqueous solution, which is used as the microneedle backing material. Take an appropriate amount of the microneedle backing material and coat it onto the upper layer of the PDMS microneedle mold. Step S7: Remove the microneedles from the mold, sonicate them in an ultrasonic instrument for 5 minutes to remove air bubbles, remove excess material from the tip of the needle, dry for 2 hours, and finally dry them in a drying oven for 24 hours (25 ℃, 30% RH) to completely dry the microneedle patch and obtain composite microneedles.

[0035] The morphology of the microneedle patch with Pt@NH2-UiO-66@Co3O4 nanoparticles loaded at the needle tip was observed by scanning electron microscopy, and the results are shown in the figure. Figure 2 .

[0036] Depend on Figure 2 It can be seen that Pt@NH2-UiO-66@Co3O4 nanoparticles are loaded at the tip of a composite microneedle with photocatalytic function, and the backing is clean with no Pt@NH2-UiO-66@Co3O4 nanoparticles present.

[0037] The tip morphology of the microneedles was characterized by SEM, such as... Figure 3 As shown, the microneedles are arrayed on the backing, with a base diameter of approximately 300 nm, a length of approximately 650 nm, and a apex angle of approximately 3°. SEM characterization results indicate that the tips are sharp and without bends, meeting the requirements for penetrating biological membranes.

[0038] Example 4: Evaluation of the bactericidal performance of composite microneedles for the repair of infectious diabetic wounds 1. The bactericidal performance of photocatalytic composite microneedles under different conditions was analyzed using the plate count method. Method: Dilute the E. coli bacterial suspension to 1 × 10⁻⁶. 8 The bacterial cultures were divided into five groups based on CFU / mL: control, Pt@NH2-UiO-66@Co3O4 nanoparticle group, photothermal group, photocatalytic group, and photothermal / photocatalytic group. The bacterial cultures of the Pt@NH2-UiO-66@Co3O4 nanoparticle group, photothermal group, photocatalytic group, and photothermal / photocatalytic group were co-incubated with 200 μg / mL Pt@NH2-UiO-66@Co3O4 nanoparticle solution for 12 h. Subsequently, the Pt@NH2-UiO-66@Co3O4 nanoparticle group and control group received no light treatment; the photothermal group was irradiated with 808 nm infrared light for 10 min; the photocatalytic group was irradiated with visible light for 1 h; and the photothermal / photocatalytic group was irradiated with visible light for 1 h followed by 808 nm infrared light for 10 min. The survival rate of E. coli bacteria in the five groups was determined using the plate count method. Replace E. coli culture with S. aureus culture and repeat the above operation to obtain the S. aureus bacterial survival rate.

[0039] See results Figure 4 ;Depend on Figure 4It is known that composite microneedles with photocatalytic function produce photocatalytic reactions under visible light irradiation and photothermal effects under infrared light irradiation, and have a good bactericidal effect under photothermal / photocatalytic combined therapy.

[0040] 2. The bactericidal performance of photocatalytic composite microneedles under different conditions was analyzed using crystal violet staining. Methods: MRSA was cultured in TSB medium to prepare a bacterial suspension. The bacterial suspension was added to 12-well plates and incubated at 30 ℃ for 24 h to form an MRSA biofilm. The biofilm was divided into a control group, an antibiotic group, a Pt@NH2-UiO-66@Co3O4 nanoparticle group, a photothermal group, a photocatalytic group, and a photothermal / photocatalytic group. The antibiotic group was treated with methicillin (80 mg / mL). Composite microneedles were inserted into the MRSA biofilm in the Pt@NH2-UiO-66@Co3O4 nanoparticle group, photothermal group, photocatalytic group, and photothermal / photocatalytic group. Subsequently, the Pt@NH2-UiO-66@Co3O4 nanoparticle group and the control group received no light treatment, while the antibiotic group received no light treatment and was treated with methicillin (40 mg / mL). The photothermal group was irradiated with 808 infrared light for 10 min, the photocatalytic group was irradiated with visible light for 1 h, and the photothermal / photocatalytic group was irradiated with visible light for 1 h followed by 10 min of 808 infrared light irradiation. All six biofilms were stained with crystal violet for 10 min, then rinsed three times with PBS and dried in a 30 ℃ incubator for 12 h. The crystal violet in the biofilms was dissolved in acetic acid, and the absorbance of the supernatant was measured.

[0041] See results Figure 5 ,Depend on Figure 5 It is known that composite microneedles with photocatalytic function produce photocatalytic reactions under visible light irradiation and photothermal effects under infrared light irradiation. Under combined photothermal / photocatalytic therapy, they have a good removal effect on biological membranes.

[0042] Example 5: Cell compatibility evaluation Methods: First, HSF cells and HUVECs cells were respectively inoculated at 1 × 10⁻⁶. 5 Cells were seeded at a density of 1 cells / well in 12-well plates, gently shaken, and incubated overnight in a sterile incubator. Subsequently, different groups of microneedles were added, and incubation continued for 24 h. After incubation, the culture medium was discarded, and the cells were washed three times with sterile PBS. Then, a mixed staining solution of Calcein-AM and propidium iodide (PI) was added, and the cells were incubated in the dark for 15 min. After staining, cell morphology and staining were observed using a fluorescence microscope. CCK-8 assay: In the CCK-8 experiment, HSF cells and HUVECs were seeded in 48-well plates (1 × 10⁻⁶ cells / well). 4Cells were added to each well (number of cells / well), shaken well, and incubated in a sterile incubator for 24 h. Then, different treatments were performed, followed by another 24 h of incubation. After incubation, the culture medium was discarded, cells were washed three times with sterile PBS, and then 200 µL of prepared CCK-8 solution was added. The cells were then incubated in the dark for 2 h. The supernatant was then transferred to 96-well plates for analysis, and the absorbance at 450 nm was measured using a microplate reader.

[0043] like Figure 6 As shown in a and b, cells co-incubated with the nanoparticles and microneedles showed no red fluorescence and emitted green fluorescence, demonstrating that both the Pt@NH2-UiO-66@Co3O4 nanoparticles and microneedles exhibit good cell compatibility. Figure 6 As shown in c and d, the cell viability calculated by the CCK-8 assay was over 80%, further demonstrating that both Pt@NH2-UiO-66@Co3O4 nanoparticles and microneedles have good cell compatibility.

[0044] like Figure 7 As shown in Figure a, co-incubation of Pt@NH2-UiO-66@Co3O4 nanoparticles and microneedles with blood does not cause hemolysis, demonstrating good safety. Figure 7 As shown in b), Pt@NH2-UiO-66@Co3O4 nanoparticles and microneedles do not affect the blood clotting ability, and both Pt@NH2-UiO-66@Co3O4 nanoparticles and microneedles have good blood compatibility.

[0045] Example 4: Microneedle regulation of macrophage polarization properties Macrophage phenotypes were characterized by flow cytometry. M1 macrophages promoted inflammation, while M2 macrophages exhibited anti-inflammatory effects and played a crucial role in wound healing. Photocatalysis produced H2, which inhibited macrophage polarization towards M1 and promoted M2 polarization.

[0046] Depend on Figure 8 As shown, flow cytometry characterizes M1 in the visible light treatment group ( Figure 8 The proportion of type a) macrophages was higher than that in the control group, but significantly lower than that in the LPS-treated group and the PUC-treated group. M2 ( Figure 8 The proportion of type b) macrophages was significantly higher than that in the control group and close to that in the IL-4 treatment group. This indicates that H2 has a certain ability to inhibit M1 macrophage phenotype polarization and promote M2 macrophage phenotype polarization, and photocatalytic therapy can regulate macrophage phenotype by generating H2. (e.g.) Figure 8 c, Figure 8 d are respectively Figure 8 a, Figure 8 (Quantitative analysis of Figure b) Example 5: Mouse animal experiment on the treatment of biofilm-infected diabetic wounds with composite microneedles. 1. Establishment of a biofilm-infected diabetic wound model A type 2 diabetes model was established using Kunming rats. During the experiment, the rats were continuously fed a high-fat diet and glucose solution. To establish the model, the mice were first subjected to a 10-hour fast, followed by an intraperitoneal injection of 1% w / v streptozotocin diluted in citrate buffer at a dose of 70 mg / kg. This treatment was repeated for three consecutive days. After modeling, blood glucose levels were monitored daily for four days. A type 2 diabetes model was considered successfully established if the blood glucose concentration stabilized and consistently remained above 16.7 mM.

[0047] Mice with a successfully established type 2 diabetes model were anesthetized using an air anesthesia machine. The hair on their backs was removed, and a circular full-skin wound with a diameter of 8 mm was created on their backs using a punch. MRSA bacterial solution with a concentration of 1x10⁸ CFU / mL was applied to the wound, and the wound was sealed with a film to prevent the bacterial solution from drying out. After 24 hours, the film was removed to obtain a biofilm-infected diabetic wound type.

[0048] 2. Compound microneedle treatment of biofilm-infected diabetic wounds in mice Composite microneedles were inserted into the wounds of mice. On the first day of treatment, the wounds were first irradiated with visible light for 1 hour, followed by irradiation with an 808 nm infrared light source for 10 minutes. On the third, fifth, and seventh days thereafter, the wounds were irradiated with visible light for 1 hour each. After the seventh day, no treatment was given and the mice were allowed to heal naturally.

[0049] The results are as follows Figure 9 As shown, the wound healing rate at different time points was statistically analyzed. Starting from day 3 of the experiment, the wound healing rate in the photothermal / photocatalytic group increased, and the healing rate was better than that in the control group. This is because the appearance of granulation tissue in the early stage of wound healing accelerates the healing process, while the gradual disappearance of granulation tissue in the later stage slows down the healing process. On day 14 of the experiment, the wounds of mice in the photothermal / photocatalytic group were completely healed, while the healing rate in the control group was only 63%. This indicates that the composite microneedle photothermal / photocatalytic treatment has a good therapeutic effect on biofilm-infected diabetic wounds.

[0050] In summary, the examples demonstrate that the composite microneedle for repairing infectious diabetic wounds of the present invention is characterized by the precise loading of Pt@NH2-UiO-66@Co3O4 nanoparticles onto the tip of the microneedle using a specific mold. Under visible light irradiation, the Pt@NH2-UiO-66@Co3O4 nanoparticles in this photocatalytic composite microneedle can undergo a photocatalytic reaction to eliminate biofilms and generate H2 to promote wound healing. Under infrared light irradiation, the nanoparticles generate a photothermal effect, synergistically killing bacteria with H2, thus exhibiting excellent therapeutic effects on biofilm-infected diabetic wounds.

[0051] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention patent. Several modifications and improvements can be made without departing from the spirit of the invention, and these modifications and improvements should also be considered within the scope of protection of the present invention.

Claims

1. A composite nanoparticle, characterized in that, The preparation method of the composite nanoparticles includes the following steps: S1. Pt nanoparticles were synthesized using a hot solvent method; S2. Pt@NH2-UiO-66 nanoparticles are obtained by coating the Pt nanoparticles obtained in step 1 with NH2-UiO-66 nanomaterials. S3. The outer layer of the Pt@NH2-UiO-66 nanoparticles obtained in step 2 is deposited with Co3O4 to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles.

2. The composite nanoparticles as described in claim 1, characterized in that, The preparation method includes the following steps: S1. Thoroughly mix chloroplatinic acid hexahydrate and polyvinylpyrrolidone to prepare a precursor solution. Stir the precursor solution magnetically at 180 °C for 10 minutes. Add excess acetone to the solution after reaction and centrifuge at 8000 rpm for 5 minutes to obtain Pt nanoparticles. Dilute the Pt nanoparticle colloidal solution to 1 mg / mL for later use. S2. Zirconium chloride and 2-aminoterephthalic acid were dissolved in DMF and stirred for 5 minutes. Then, acetic acid and Pt nanoparticles prepared in step 1 were added to the mixed solution and stirred for 5 minutes to prepare a precursor solution. Finally, the precursor solution was added to a hydrothermal reactor and reacted for 12 hours. The final product was collected by centrifugation and washed three times with DMF and methanol respectively. After drying, it was annealed at 200 °C for 2 hours under N2 gas protection to obtain Pt@NH2-UiO-66 nanoparticles. S3. Dissolve cobalt nitrate hexahydrate and potassium iodate in deionized water, add 1 mL of 25% ammonia, stir magnetically and heat in a water bath to 60 °C, wash three times with RO water, and dry in an oven to obtain Co3O4 nanoparticles. S4. Dissolve cobalt nitrate hexahydrate in RO water and add it to the reaction system of step 3. After the temperature is raised to 60 ℃, react for 3 h. Collect the final product by centrifugation and wash it three times with RO water. Sonicate the final product multiple times and centrifuge it in a gradient to wash away the free Co3O4 nanoparticles. Dry it in an oven to obtain Pt@NH2-UiO-66@Co3O4 nanoparticles.

3. The composite nanoparticles as described in claim 2, characterized in that, The composite nanoparticles have a particle size of 100~130 nm.

4. The application of the composite nanoparticles as described in claim 1 in the preparation of pharmaceutical formulations for treating biofilm-infected diabetic wounds and other adjunctive medical products.

5. The application in the pharmaceutical preparation and other auxiliary medical products as described in claim 4, characterized in that, The pharmaceutical preparation further contains other active pharmaceutical ingredients.

6. The application in the pharmaceutical preparation and other auxiliary medical products as described in claim 4, characterized in that, The active pharmaceutical ingredient is selected from one or more of exenatide, benaglutide, liraglutide, dulaglutide, and insulin.

7. The application in the pharmaceutical preparation and other auxiliary medical products as described in claim 4, characterized in that, The other auxiliary medical products are selected from one or more of the following: drug delivery systems, diabetes infection detection kits, combination drug adjuvants, and capsule coating agents.

8. A composite microneedle, characterized in that, The composite microneedle consists of a needle tip containing the composite nanoparticles as described in claim 1 and a backing containing an aqueous solution of polyvinyl alcohol.

9. The composite microneedle as described in claim 8, characterized in that, The composite microneedle has a base diameter of 200~450 nm, a length of 600~750 nm, and an apex angle of 2°~4°.

10. The use of the composite microneedles as described in claim 8 in the preparation of a wound repair drug for treating biofilm-infected diabetic wounds.

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