Space-time cascade wound dressing as well as preparation method and application thereof

Abstract

The invention discloses preparation and application of a space-time cascade wound dressing, relates to the technical field of biomedical materials, and solves the problems of limited depth and poor treatment effect when a diabetes infected wound is treated in the prior art. The space-time cascade wound dressing is composed of a hydrogel patch and a soluble microneedle array. The hydrogel patch comprises polyvinyl alcohol, sodium alginate, nano-enzyme, a color reagent for indicating pH and the like, has the functions of oxidation resistance and sterilization, and can monitor the state of the wound surface in real time according to the pH change indication of the wound surface; the soluble microneedle array comprises a soluble polymer and glucose oxidase, and has the functions of deep sterilization and local blood glucose reduction. According to the space-time cascade wound dressing provided by the invention, two treatment forms of the hydrogel patch and the soluble microneedle array are integrated, and a nano enzyme and a natural enzyme catalytic system capable of generating cascade catalytic reaction are respectively introduced into the hydrogel patch and the soluble microneedle array, so that a multifunctional treatment system with a space-time cascade catalytic effect is formed; and comprehensive treatment and real-time monitoring of multi-layer wound surfaces are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a spatiotemporal cascade wound dressing and a preparation method and application thereof. Background Art

[0002] Diabetes is a common metabolic disease, the main feature of which is that blood sugar levels remain high for a long time, and it is related to abnormal secretion and action of insulin. Patients with diabetes often have various acute and chronic complications, such as diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, and diabetic foot ulcers. Among them, diabetic infected wounds (such as diabetic foot ulcers) are one of the most common and serious complications. Due to the high blood sugar, high inflammation and high infection state of the local microenvironment, these wounds often heal slowly and are prone to infection and tissue necrosis. In severe cases, amputation may even be required, which has a great impact on the patient's quality of life and survival rate. Traditional wound treatment methods mostly rely on topical drugs and dressings, which can help protect the wound, absorb exudate, and reduce infection to a certain extent. However, these methods are often difficult to effectively control the special tissue microenvironment of diabetic wounds, and their effects on deep infections are very limited.

[0003] In recent years, hydrogel patches have been widely used in wound care due to their excellent biocompatibility and moisturizing properties. The unique structure of hydrogels can effectively keep the wound moist, promote cell migration and proliferation, and thus accelerate wound healing. In addition, hydrogel patches also have good air permeability, which helps prevent infection and promote wound healing. However, despite the many advantages of hydrogels in wound care, there are still some significant deficiencies in practical applications. First, the therapeutic effect of hydrogel patches is often affected by factors such as wound infection and hypoxia, resulting in a slow healing rate. Secondly, the action depth of traditional hydrogels is limited, and it is difficult to effectively penetrate into the deep tissue of the wound, and it cannot meet the comprehensive treatment needs for deep infection and high concentrations of glucose. In addition, when facing a more complex wound environment, the antibacterial and antioxidant abilities of hydrogels are also insufficient, which limits their application in the treatment of diabetic infection wounds.

[0004] As an emerging drug delivery system, microneedle technology has attracted widespread attention because of its ability to effectively penetrate the surface of the skin and deliver drugs directly to deep tissues. Soluble microneedle arrays can achieve efficient drug release without causing obvious pain, and are particularly suitable for the treatment of diabetic wounds. However, microneedles have limitations in treating diabetic infected wounds, such as easy detachment or the need for additional fixation, which makes it difficult to meet clinical needs. Summary of the invention

[0005] In order to solve the problems of limited depth of action of simple hydrogel patches and poor skin adhesion and therapeutic effect of simple soluble microneedles in the comprehensive treatment and monitoring of diabetic infection wounds in the prior art, and to fully utilize and regulate the special tissue microenvironment of diabetic infection wounds to achieve the purpose of promoting wound healing, the present invention proposes the preparation and application of a spatiotemporal cascade wound dressing. The present invention integrates two seemingly mutually exclusive treatment forms, hydrogel patches and soluble microneedle arrays, and introduces nanozymes and natural enzyme catalytic systems that can produce cascade catalytic reactions, so as to achieve orderly regulation of multiple factors in the microenvironment of diabetic infection wounds and promotion of wound healing in two stages and two spaces. The technical solution of the present invention is as follows:

[0006] A spatiotemporal cascade wound dressing, consisting of a hydrogel patch and a soluble microneedle array.

[0007] Furthermore, the hydrogel patch comprises the following components by mass fraction: 10-20wt% polyvinyl alcohol, 0.5-5wt% sodium alginate, 0.01-0.05wt% nanozyme, 0.1-0.5wt% colorimetric reagent indicating pH, aqueous solvent, 0.1-5wt% calcium chloride, and 0.1-2wt% glycerol;

[0008] Furthermore, the mass ratio of polyvinyl alcohol, sodium alginate and calcium ion is 10:(0.5-2):(0.1-0.5);

[0009] Furthermore, the polyvinyl alcohol is one of 1750±50, 1788, and 1799 or a combination of at least two of them, preferably a polyvinyl alcohol of 1750±50 and 1788 mixed in a ratio of 1:1;

[0010] Further, the nanozyme comprises one or a combination of at least two of manganese oxide, cerium oxide, cobalt oxide, iron oxide, gold nanoparticles and polydopamine / manganese dioxide hybrid nanoparticles having catalase-like activity, preferably a cascade nanozyme-polydopamine / manganese dioxide hybrid nanoparticle having photothermal conversion ability and superoxide dismutase-like activity and catalase-like activity;

[0011] Furthermore, the color developing reagent indicating pH includes any one of anthocyanin, phenol red, and methyl red;

[0012] Furthermore, the aqueous solvent includes one or a combination of at least two of water, physiological saline, and buffer solution, preferably water, and the water may be one or a combination of at least two of secondary water, deionized water, ultrapure water, or distilled water;

[0013] Furthermore, the soluble microneedle array comprises the following components, calculated by mass fraction: 5-40 wt% of soluble polymer, 0.1-1 wt% of glucose oxidase, and an aqueous solvent;

[0014] Furthermore, the soluble polymer includes one or a combination of at least two of sodium hyaluronate, polyvinyl alcohol, hydrolyzed collagen, silk fibroin, trehalose, chitosan, polyglutamic acid and polylysine, preferably sodium hyaluronate, and the molecular weight of the sodium hyaluronate is one or a combination of at least two of 5kDa, 10kDa, 10-20kDa.

[0015] A method for preparing a spatiotemporal cascade wound dressing comprises the following steps:

[0016] S1: polyvinyl alcohol, sodium alginate, nanozyme and a colorimetric reagent indicating pH are mixed in an aqueous solvent to obtain a precursor A solution of a hydrogel patch;

[0017] S2: Mixing calcium chloride and glycerol in an aqueous solvent to obtain a precursor B solution of a hydrogel patch;

[0018] S3: mixing a soluble polymer and glucose oxidase in an aqueous solvent to obtain a precursor solution of a soluble microneedle array;

[0019] S4: adding solution A to a mold for low-temperature freezing, and after freezing, returning the mold to room temperature to obtain a hydrogel, adding solution B to the outer surface of the hydrogel to further cross-link the two to obtain a hydrogel patch, and finally, drying the hydrogel patch in a drying oven, and after drying, cutting it into backing patches for later use;

[0020] S5: adding the precursor solution of the soluble microneedle array into the microneedle mold, allowing the solution to enter the needle tip groove of the mold by vacuum filtration, scraping off the excess liquid, and coating the inner surface of the backing patch prepared in S4 with the precursor solution of the soluble microneedle array, and then covering it on the microneedle mold;

[0021] S6: Dry the sample in an oven for 24 hours, then transfer it to a dryer and continue drying it for 24 hours. After demolding, the spatiotemporal cascade wound dressing is obtained.

[0022] Further, in S3, the temperature of the aqueous solvent is 4°C;

[0023] Furthermore, in S4, the low-temperature freezing temperature is -20°C, and the low-temperature freezing time is 2 to 6 hours;

[0024] Furthermore, in S4, the hydrogel patch is dried in a drying oven at a temperature of 37° C. for a drying time of 12 hours.

[0025] Further, in S5, the vacuum filtration time is 5 to 10 minutes;

[0026] Furthermore, in S6, the drying temperature in the oven is 37°C.

[0027] Compared with the prior art, the present invention not only solves the problem that the depth of a simple hydrogel patch on a diabetic infected wound is limited and that a simple soluble microneedle is easy to fall off, resulting in poor therapeutic effect, but also can fully utilize and regulate the special tissue microenvironment of the diabetic infected wound to achieve the purpose of promoting wound healing. The specific beneficial effects are:

[0028] (1) Enhance the depth and breadth of wound treatment: The hydrogel patch is combined with a soluble microneedle array. The microneedle array can penetrate the skin and quickly dissolve to deliver drugs to deep tissues. The hydrogel patch absorbs wound exudate and changes from a dry state back to a gel state, providing protection and therapeutic effects on the surface. This effectively overcomes the problems of limited treatment depth of a simple hydrogel patch and the lack of skin surface treatment effects of simple microneedles.

[0029] (2) Highly effective antibacterial and antioxidant functions: The nanozymes in the hydrogel patch of the spatiotemporal cascade wound dressing have photothermal properties, as well as superoxide dismutase-like and catalase-like activities, which can efficiently remove reactive oxygen species (such as hydrogen peroxide and superoxide free radicals) generated in the wound and convert them into non-toxic water and oxygen, thereby achieving anti-inflammatory and antioxidant effects and promoting wound healing. The glucose oxidase in the soluble microneedle array catalyzes the glucose in the wound to produce gluconic acid and hydrogen peroxide, thereby removing bacteria in the deep wound. At the same time, the generated hydrogen peroxide can also diffuse to the outside of the wound and undergo a cascade catalytic reaction with the nanozymes in the hydrogel patch, converting them into non-toxic water and oxygen.

[0030] (3) Photothermal therapy and biofilm removal function: The hydrogel patch has photothermal conversion capability and can be stimulated by an external light source to produce a thermal effect to kill bacteria and remove biofilm, thereby improving the wound microenvironment.

[0031] (4) Local hypoglycemic and deep sterilization: The glucose oxidase carried by the soluble microneedle array can convert high-concentration glucose into gluconic acid and hydrogen peroxide in the deep wound surface, achieving the effects of local hypoglycemic and deep sterilization, and effectively controlling the infection.

[0032] (5) Reduce wound interference and enhance safety: The soluble microneedles dissolve quickly after drug delivery, avoiding mechanical interference with wound healing. At the same time, excess hydrogen peroxide will be quickly degraded by the nanozymes in the hydrogel patch, reducing potential damage to normal tissues.

[0033] (6) Real-time monitoring of wound status: A colorimetric reagent is added to the spatiotemporal cascade wound dressing, which can indicate the wound status based on the pH changes of the wound, helping to adjust the treatment plan in a timely manner and optimize wound management.

[0034] (7) Good biocompatibility and adhesion: Hydrogel patches have excellent biocompatibility and certain tissue adhesion ability, which can prevent the dressing from falling off and reduce patient discomfort.

[0035] (8) Innovative comprehensive treatment and monitoring system: Through the antioxidant and bactericidal functions of the hydrogel patch and the deep bactericidal and local hypoglycemic effects of the microneedle array, a multifunctional treatment system with a spatiotemporal cascade catalytic effect is formed, achieving multi-level comprehensive wound treatment and real-time monitoring, providing patients with diabetic infected wounds with safer and more effective treatment options. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a diagram showing the mechanism of action of the spatiotemporal cascade wound dressing of the present invention;

[0037] Figure 2 This is a physical picture of the spatiotemporal cascade wound dressing obtained in Example 1;

[0038] Figure 3 This is a comparison chart of the in vitro cytotoxicity of the samples in Examples 1-4;

[0039] Figure 4 It is a comparison chart of the in vitro hypoglycemic effects of the samples in Example 1 and Comparative Examples 1-3;

[0040] Figure 5 This is a test chart of the pH indication effect of the sample in Example 1.

[0041] Figure 6 This is a test diagram of the adhesion of the sample in Example 1. DETAILED DESCRIPTION

[0042] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as a limitation to the present invention.

[0043] Example 1.

[0044] This embodiment provides a spatiotemporal cascade wound dressing, and the specific preparation method is as follows:

[0045] (1) Preparing a precursor A solution of a hydrogel patch, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate, 0.05wt% polydopamine / manganese dioxide hybrid nanoparticles and 0.1wt% colorimetric reagent indicating pH, adding 5mL of the precursor A solution of the hydrogel patch into a circular mold with a diameter of 90mm, placing it in a refrigerator at -20°C for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a precursor B solution of a hydrogel patch, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the precursor B solution of the hydrogel patch to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying the hydrogel patch in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for standby use.

[0046] (2) Prepare a precursor solution of a soluble microneedle array, whose components include 40wt% sodium hyaluronate and 1wt% glucose oxidase, add 0.2mL of the precursor solution of the soluble microneedle array into the microneedle mold, and allow the solution to enter the needle tip groove of the mold by vacuum filtration for 10 minutes, then scrape off the excess liquid, coat the inner surface of the backing patch prepared in step (1) with the soluble microneedle array precursor solution, and then cover it on the microneedle mold; finally, dry the sample in a 37°C oven for 24 hours, transfer it to a dryer and continue drying for 24 hours, and obtain a spatiotemporal cascade wound dressing after demolding. Figure 1 As shown, it is a diagram showing the mechanism of action of the spatiotemporal cascade wound dressing of the present invention. Figure 2 This is a physical picture of the spatiotemporal cascade wound dressing prepared in Example 1.

[0047] Example 2.

[0048] This embodiment provides a spatiotemporal cascade wound dressing, and the specific preparation method is as follows:

[0049] (1) Preparing a precursor A solution of a hydrogel patch, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate, 0.01wt% polydopamine / manganese dioxide hybrid nanoparticles and 0.1wt% colorimetric reagent indicating pH, adding 5mL of the precursor A solution of the hydrogel patch into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a precursor B solution of a hydrogel patch, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the precursor B solution of the hydrogel patch to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying the hydrogel patch in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for later use.

[0050] (2) preparing a precursor solution of a soluble microneedle array, the components of which include 40 wt % sodium hyaluronate and 1 wt % glucose oxidase, adding 0.2 mL of the precursor solution of the soluble microneedle array into a microneedle mold, and allowing the solution to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then scraping off excess liquid, coating the inner surface of the backing patch prepared in step (1) with the soluble microneedle array precursor solution, and then covering it on the microneedle mold; finally, drying the sample in an oven at 37° C. for 24 hours, transferring it to a dryer and continuing to dry it for 24 hours, and obtaining a spatiotemporal cascade wound dressing after demolding.

[0051] Example 3.

[0052] This embodiment provides a spatiotemporal cascade wound dressing, and the specific preparation method is as follows:

[0053] (1) Preparing a hydrogel patch precursor A solution, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate, 0.05wt% polydopamine / manganese dioxide hybrid nanoparticles and 0.1wt% pH-indicating color developing reagent, adding 5mL of the hydrogel patch precursor A solution into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a hydrogel patch precursor B solution, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the hydrogel patch precursor B solution to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying it in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for use.

[0054] (2) preparing a precursor solution of a soluble microneedle array, the components of which include 40 wt % sodium hyaluronate and 0.5 wt % glucose oxidase, adding 0.2 mL of the precursor solution of the soluble microneedle array into a microneedle mold, and allowing the solution to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then scraping off excess liquid, coating the inner surface of the backing patch prepared in step (1) with the soluble microneedle array precursor solution, and then covering it on the microneedle mold; finally, drying the sample in an oven at 37° C. for 24 hours, transferring it to a dryer and continuing to dry it for 24 hours, and obtaining a spatiotemporal cascade wound dressing after demolding.

[0055] Example 4.

[0056] This embodiment provides a spatiotemporal cascade wound dressing, and the specific preparation method is as follows:

[0057] (1) Preparing a hydrogel patch precursor A solution, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate, 0.01wt% polydopamine / manganese dioxide hybrid nanoparticles and 0.1wt% pH-indicating colorimetric reagent, adding 5mL of the hydrogel patch precursor A solution into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours, and then returning it to room temperature to obtain a hydrogel; preparing a hydrogel patch precursor B solution, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the hydrogel patch precursor B solution to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying it in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for standby use.

[0058] (2) preparing a precursor solution of a soluble microneedle array, the components of which include 40 wt % sodium hyaluronate and 0.5 wt % glucose oxidase, adding 0.2 mL of the precursor solution of the soluble microneedle array into a microneedle mold, and allowing the solution to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then scraping off excess liquid, coating the inner surface of the backing patch prepared in step (1) with the soluble microneedle array precursor solution, and then covering it on the microneedle mold; finally, drying the sample in an oven at 37° C. for 24 hours, transferring it to a dryer and continuing to dry it for 24 hours, and obtaining a spatiotemporal cascade wound dressing after demolding.

[0059] Comparative Example 1.

[0060] This comparative example provides a wound dressing, and the specific preparation method is as follows:

[0061] (1) Preparing a hydrogel patch precursor A solution, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate and 0.1wt% pH-indicating color developing reagent, adding 5mL of the hydrogel patch precursor A solution into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a hydrogel patch precursor B solution, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the hydrogel patch precursor B solution to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying it in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for use.

[0062] (2) preparing a precursor solution of a soluble microneedle array, the components of which include 40 wt% sodium hyaluronate and 0.5 wt% glucose oxidase, adding 0.2 mL of the precursor solution of the soluble microneedle array into a microneedle mold, and allowing the solution to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then scraping off excess liquid, coating the inner surface of the backing patch prepared in step (1) with the soluble microneedle array precursor solution, and then covering it on the microneedle mold; finally, drying the sample in an oven at 37° C. for 24 hours, transferring it to a dryer and continuing to dry it for 24 hours, and obtaining a wound dressing after demolding.

[0063] Comparative Example 2.

[0064] The comparative example provides a wound dressing, and the specific preparation method is as follows:

[0065] (1) Preparing a hydrogel patch precursor A solution, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate, 0.05wt% polydopamine / manganese dioxide hybrid nanoparticles and 0.1wt% pH-indicating color developing reagent, adding 5mL of the hydrogel patch precursor A solution into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a hydrogel patch precursor B solution, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the hydrogel patch precursor B solution to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying it in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for use.

[0066] (2) Using 40 wt % sodium hyaluronate to prepare a precursor solution of a soluble microneedle array, 0.2 mL of the precursor solution of the soluble microneedle array is added to the microneedle mold, and the solution is allowed to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then, the excess liquid is scraped off, and the inner surface of the backing patch prepared in step (1) is coated with the soluble microneedle array precursor solution, and then covered on the microneedle mold; finally, the sample is dried in an oven at 37° C. for 24 hours, and transferred to a dryer for further drying for 24 hours, and a wound dressing is obtained after demolding.

[0067] Comparative Example 3.

[0068] The comparative example provides a wound dressing, and the specific preparation method is as follows:

[0069] (1) Preparing a hydrogel patch precursor A solution, whose components include 10wt% polyvinyl alcohol, 1wt% sodium alginate and 0.1wt% pH-indicating color developing reagent, adding 5mL of the hydrogel patch precursor A solution into a circular mold with a diameter of 90mm, placing it in a -20°C refrigerator and freezing it for 2 hours and then returning it to room temperature to obtain a hydrogel; preparing a hydrogel patch precursor B solution, whose components include 4wt% calcium chloride and 0.1wt% glycerol; then adding 1mL of the hydrogel patch precursor B solution to the outer surface of the hydrogel, so that the two are further cross-linked to obtain a hydrogel patch; finally, drying it in a 37°C forced air drying oven for 12 hours, and cutting it into a circular backing patch with a diameter of 12mm for use.

[0070] (2) Using 40 wt % sodium hyaluronate to prepare a precursor solution of a soluble microneedle array, 0.2 mL of the precursor solution of the soluble microneedle array is added to the microneedle mold, and the solution is allowed to enter the needle tip groove of the mold by vacuum filtration for 10 minutes; then, the excess liquid is scraped off, and the inner surface of the backing patch prepared in step (1) is coated with the soluble microneedle array precursor solution, and then covered on the microneedle mold; finally, the sample is dried in an oven at 37° C. for 24 hours, and transferred to a dryer for further drying for 24 hours, and a wound dressing is obtained after demolding.

[0071] CCK8 cytotoxicity test:

[0072] The CCK8 cytotoxicity test was performed on the samples prepared in Examples 1 to 4, and the specific method is as follows:

[0073] Mouse fibroblast L929 was inoculated into a 96-well plate and cultured for 24 hours at a cell density of 1×105 / mL. Six replicate wells were set up in each group. Cells cultured in fresh culture medium were used as the control group; cells cultured in the extract of the samples prepared in Examples 1 to 4 for 24 hours were used as the experimental group. After the treatment, the culture medium containing the extract was removed, washed 3 times with PBS, and the culture medium containing CCK8 was added to continue incubation at 37°C for 30 minutes. The absorbance at 450nm was tested using an ELISA instrument, and the cell survival rate was calculated.

[0074] The extracts of the samples prepared in Examples 1 to 4 were obtained by leaching 5 mL of complete culture medium for 24 hours; the mouse fibroblast L929 was provided by the ATCC Collection Center.

[0075] Test results such as Figure 3 As shown, it can be seen that after the samples prepared in Examples 1 to 4 were incubated with L929 cells, the survival rate of each group of cells was above 95%, indicating that the samples in Examples 1 to 4 had no cytotoxicity and good biosafety.

[0076] Hypoglycemic effect test:

[0077] The samples of Example 1 and Comparative Examples 1 to 3 were tested for their hypoglycemic effects in vitro, and the specific method was as follows: a 15 mM glucose aqueous solution was prepared, and the samples of Example 1 and Comparative Examples 1 to 3 were incubated with 2 mL of the glucose aqueous solution at 37° C. for 6 hours. Subsequently, the remaining glucose content in each solution was tested using a glucose detection kit, and the glucose consumption ratio of each group of samples was calculated.

[0078] Test results such as Figure 4 As shown, it can be seen that the samples of Example 1 and Comparative Example 1 containing glucose oxidase exhibit excellent glucose consumption capabilities, and the sample of Example 1 having a spatiotemporal cascade catalytic effect has a stronger glucose consumption capability than Comparative Example 1 under the same conditions. However, the samples of Comparative Examples 2 to 3 without glucose oxidase have almost no glucose consumption capability.

[0079] pH indicator test:

[0080] The pH indicator test was performed on the sample of Example 1, and the specific method is as follows:

[0081] PBS solutions with pH values ​​of 4, 5, 6, 7 and 8 were prepared, and the samples of Example 1 were incubated with 200 μl of PBS solutions with different pH values ​​for 10 minutes respectively. The excess liquid on the surface of the samples was absorbed with filter paper, and the color of the spatiotemporal cascade wound dressing was observed.

[0082] Test results such as Figure 5 As shown, it can be seen that the sample of Example 1 shows a color change from yellow to orange-red after absorbing PBS solutions with pH values ​​of 4, 5, 6, 7 and 8, indicating that the dressing can effectively indicate the pH value of the microenvironment of the affected area by color.

[0083] Adhesion test:

[0084] The adhesion test was performed on the sample of Example 1, and the specific method is as follows:

[0085] The samples of Example 1 were incubated with 200 μl of PBS solution for 10 minutes respectively, and the excess liquid on the surface of the patch was absorbed with filter paper. Then, the adhesion of the samples to wet pig skin, glass and volunteer skin was tested.

[0086] Test results such as Figure 6 As shown, it can be seen that the sample of Example 1 has good adhesion to wet pig skin, glass and volunteer skin.

[0087] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A spatiotemporal cascade wound dressing, characterized in that: It consists of a hydrogel patch and a dissolvable microneedle array; The hydrogel patch comprises the following components by mass fraction: 10-20wt% polyvinyl alcohol, 0.5-5wt% sodium alginate, 0.01-0.05wt% nanozyme, 0.1-0.5wt% colorimetric reagent indicating pH, aqueous solvent, 0.1-5wt% calcium chloride, and 0.1-2wt% glycerol; The soluble microneedle array comprises the following components by mass fraction: 5-40wt% of soluble polymer, 0.1-1wt% of glucose oxidase, and aqueous solvent.

2. The spatiotemporal cascade wound dressing according to claim 1, characterized in that: The mass ratio of the polyvinyl alcohol, sodium alginate and calcium ions is 10:(0.5-2):(0.1-0.5); The polyvinyl alcohol is one of the types 1750±50, 1788, and 1799, or a combination of at least two of them; The nanozyme comprises one or a combination of at least two of manganese oxide, cerium oxide, cobalt oxide, iron oxide, gold nanoparticles and polydopamine / manganese dioxide hybrid nanoparticles.

3. The spatiotemporal cascade wound dressing according to claim 1, characterized in that: The nanozyme is a cascade nanozyme: polydopamine / manganese dioxide hybrid nanoparticles.

4. The spatiotemporal cascade wound dressing according to claim 1, characterized in that: The color developing reagent indicating pH includes any one of anthocyanin, phenol red, and methyl red; The aqueous solvent includes one or a combination of at least two of water, physiological saline, and buffer solution; The soluble polymer includes one or a combination of at least two of sodium hyaluronate, polyvinyl alcohol, hydrolyzed collagen, silk fibroin, trehalose, chitosan, polyglutamic acid and polylysine.

5. A method for preparing a spatiotemporal cascade wound dressing, characterized in that: The following steps are involved: S1: polyvinyl alcohol, sodium alginate, nanozyme and a colorimetric reagent indicating pH are mixed in an aqueous solvent to obtain a precursor A solution of a hydrogel patch; S2: Mixing calcium chloride and glycerol in an aqueous solvent to obtain a precursor B solution of a hydrogel patch; S3: mixing a soluble polymer and glucose oxidase in an aqueous solvent to obtain a precursor solution of a soluble microneedle array; S4: adding solution A to a mold for low-temperature freezing, and after freezing, returning the mold to room temperature to obtain a hydrogel, adding solution B to the outer surface of the hydrogel to further cross-link the two to obtain a hydrogel patch, and finally, drying the hydrogel patch in a drying oven, and after drying, cutting it into backing patches for later use; S5: adding the precursor solution of the soluble microneedle array into the microneedle mold, allowing the solution to enter the needle tip groove of the mold by vacuum filtration, scraping off the excess liquid, and coating the inner surface of the backing patch prepared in S4 with the precursor solution of the soluble microneedle array, and then covering it on the microneedle mold; S6: Dry the sample in an oven for 24 hours, then transfer it to a dryer and continue drying it for 24 hours. After demolding, the spatiotemporal cascade wound dressing is obtained.

6. The method for preparing the spatiotemporal cascade wound dressing according to claim 5, characterized in that: The temperature of the aqueous solvent described in S3 is 4°C.

7. The method for preparing the spatiotemporal cascade wound dressing according to claim 5, characterized in that: The low-temperature freezing temperature of S4 is -20°C, and the low-temperature freezing time is 2 to 6 hours; the drying temperature of the hydrogel patch in the drying oven is 37°C, and the drying time is 12 hours.

8. The method for preparing the spatiotemporal cascade wound dressing according to claim 5, characterized in that: The vacuum filtration time described in S5 is 5 to 10 minutes.

9. The method for preparing the spatiotemporal cascade wound dressing according to claim 5, characterized in that: The drying temperature in the oven described in S6 is 37°C.

10. Use of the spatiotemporal cascade wound dressing according to any one of claims 1 to 4 or the spatiotemporal cascade wound dressing prepared by the method for preparing the spatiotemporal cascade wound dressing according to any one of claims 5 to 9, characterized in that: It is used to prepare diabetic infection wound repair materials.

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