Polyhydroxyalkanoate electrostatic spinning wound dressing as well as preparation method and application thereof

Abstract

The invention relates to the technical field of medical materials, and particularly discloses a polyhydroxyalkanoate electrostatic spinning wound dressing as well as a preparation method and application thereof. PHA with good biocompatibility, a hydrophilic high-molecular polymer and a micromolecular drug with an anti-inflammatory effect are dissolved in an organic solvent, and the non-adhesive wound dressing with high efficiency, anti-inflammatory property and good biocompatibility is prepared through an electrostatic spinning technology. The problems that an existing wound dressing is prone to being adhered to a wound surface to cause mechanical injury and poor in biocompatibility to cause inflammation are solved, meanwhile, multiple functions such as drug sustained release, inflammation resistance, cell proliferation and angiogenesis promotion and wound surface tissue adhesion prevention are achieved, and the wound dressing has wide application prospects and considerable market value.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a polyhydroxyalkanoate (PHA) electrospinning wound dressing, a preparation method thereof, and applications thereof. Background Art

[0002] Chronic wounds can result from a variety of etiologies, including venous lower limb ulcers, arterial ulcers, diabetic foot ulcers, pressure sores, and burns. Globally, the incidence of chronic wounds is increasing as the prevalence of related diseases increases. These chronic wounds heal slowly and are susceptible to infection, severely impacting patients' quality of life and even leading to amputation. Chronic wounds often experience excessive inflammatory responses, which hinder the wound's re-epithelialization process. Dressing therapy is the preferred treatment for chronic wounds. Traditional wound dressings, such as gauze, simply provide coverage and fail to meet the complex needs of chronic wound healing. These dressings are often made of synthetic or natural fibers, have poor biocompatibility, and are prone to adhesion to the wound, leading to secondary damage during dressing changes and exacerbating the risk of inflammation and infection. Therefore, the development of wound dressings that combine biocompatibility, anti-adhesion, and anti-inflammatory properties to promote the healing of chronic wounds has become an urgent clinical need.

[0003] At present, in order to overcome the limitations of traditional dressings, drugs have been directly applied to the surface of gauze or dressings to prepare drug-loaded dressings. However, there are still many shortcomings. First, drug release is difficult to control, and initial burst release is prone to occur, resulting in excessive local drug concentration and toxic side effects, while insufficient release in the later stage affects the efficacy. Secondly, the drug is prone to degradation or inactivation, which reduces the bioavailability of the drug. In addition, the dressing exposed after drug release has strong adhesion to the wound tissue, which can easily cause secondary damage during dressing changes, increasing the patient's pain.

[0004] In recent years, biocompatible polymer materials, particularly electrospun nanofibers, have shown great potential in wound dressings. Nanofibers produced using electrospinning technology have a three-dimensional structure similar to the natural extracellular matrix, which promotes cell proliferation and migration, accelerating wound healing. However, current commercial electrospun dressings often have limited functionality and struggle to simultaneously achieve multiple functions, such as sustained drug release, anti-inflammatory effects, cell proliferation, and angiogenesis. Therefore, they cannot meet the complex needs of chronic wounds. Summary of the Invention

[0005] The present invention aims to overcome at least one of the shortcomings of the above-mentioned prior arts and provide a polyhydroxyalkanoate (PHA) electrospun wound dressing and its preparation method and application, which can be used to solve the problems that existing wound dressings are prone to adhesion to the wound, causing mechanical damage, poor biocompatibility and easy to induce inflammation, while achieving multiple functions such as sustained release of drugs, anti-inflammatory, promotion of cell proliferation and angiogenesis, and prevention of adhesion of wound tissue.

[0006] The technical solution adopted by the present invention is to provide a method for preparing a PHA electrospinning wound dressing, comprising the following steps:

[0007] S1: dissolving a PHA polymer, a hydrophilic high molecular weight polymer, and an anti-inflammatory small molecule drug in an organic solvent to obtain a PHA-containing mixed solution;

[0008] S2: electrospinning the PHA-containing mixed solution obtained in step S1 into an electrospun film;

[0009] S3: Drying the electrospun film obtained in step S2 to remove the organic solvent to obtain a PHA electrospun wound dressing.

[0010] The present application achieves at least four technical effects by dissolving PHA with a hydrophilic polymer and an anti-inflammatory small molecule drug in an organic solvent and spinning it through electrospinning technology to obtain an electrospun film. First, the hydrophilic polymer can absorb wound exudate to a certain extent, which can effectively prevent the accumulation of exudate on the wound surface, leading to bacterial growth, and thus increasing the risk of wound infection. Second, the anti-inflammatory small molecule drug can be gradually and slowly released as the hydrophilic polymer absorbs water, thereby improving the bioavailability of the drug, while exerting the anti-inflammatory effect on the wound without causing toxic side effects caused by excessive drug concentration to the tissue. Third, the hydrophilic polymer dissolves after absorbing water and forms some holes on the surface of the fiber, which increases the contact area between the dressing and the wound, and is conducive to cell attachment, growth and angiogenesis. Fourth, PHA gives the electrospun wound dressing good hydrophobicity while ensuring good biocompatibility, so that it does not have strong adhesion to the wound tissue, reducing the risk of secondary damage caused by wound tissue peeling during dressing changes.

[0011] Furthermore, in step S1, the concentration ratio of the PHA polymer, the hydrophilic high molecular polymer, and the anti-inflammatory small molecule drug is (80-120):(80-120):(0.5-2).

[0012] Preferably, in step S1, the concentration ratio of the PHA polymer, the hydrophilic high molecular polymer, and the anti-inflammatory small molecule drug is (80-120):(80-120):1.

[0013] Furthermore, the concentration of the PHA polymer in step S1 is 5 to 20% wt.

[0014] Furthermore, the PHA polymer described in step S1 includes one or more of PHB, P4HB, PHBV, P34HB, and PHBHHx.

[0015] Furthermore, the hydrophilic high molecular polymer in step S1 includes one or more of polyvinyl pyrrolidone, polyhydroxyethyl methyl methacrylate, polyacrylic acid or poly(polyethylene glycol methyl ether methacrylate).

[0016] Furthermore, the anti-inflammatory drug in step S1 includes one or more of curcumin, baicalin, paeoniflorin, and aloe extract.

[0017] Furthermore, the organic solvent in step S2 includes one of hexafluoroisopropanol, dichloromethane, and dimethylacetamide.

[0018] Furthermore, the electrospinning parameters in step S2 are: temperature 15-25° C., humidity 20-35%, stainless steel needle 18-21 gauge, injection rate 0.5-2.5 mL / h, and voltage 18-28 kV.

[0019] Furthermore, the film collecting conditions in step S2 are: using a release film wrapped on a drum for collection, and the drum rotation speed is 500-1500 rpm.

[0020] Furthermore, the drying temperature in step S3 is 30-60° C., and the drying time is 2-12 hours.

[0021] Furthermore, the thickness of the electrospun wound dressing obtained in step S3 is 0.1 to 0.5 mm. The thickness of the dressing can ensure that the wound area can withstand a certain amount of traction and deformation during exercise, so that the wound is not easily ruptured.

[0022] Furthermore, the fiber pore size of the electrospun wound dressing obtained in step S3 is 8 to 25 μm. A smaller fiber pore size is beneficial for preventing cells from extending into the dressing and causing adhesion.

[0023] Another object of the present invention is to provide a PHA electrospun wound dressing obtained by the above preparation method.

[0024] Another object of the present invention is to provide application of the above-mentioned PHA electrospun wound dressing in wound repair.

[0025] Furthermore, the wound is located in the wall of the digestive tract. The structure of the wall of the digestive tract and the environment in which it is located put forward higher requirements for the repair of wounds there: first, the digestive tract is rich in blood vessels, so when repairing the wound, it is necessary to promote angiogenesis and prevent the adhesion of tissues and dressings, which will cause the wound to rupture and bleed when the dressing is removed; secondly, there is mucus on the inner wall of the digestive tract, which makes tissue adhesion more likely to occur during the wound repair process; in addition, the digestive tract is rich in flora and is more prone to inflammation than other parts. The PHA electrospinning wound dressing provided by the present invention can simultaneously achieve multiple functions such as sustained release of drugs, anti-inflammation, promotion of cell proliferation and angiogenesis, and prevention of adhesion of wound tissue, and is particularly suitable for wound repair of the wall of the digestive tract.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a polyhydroxyalkanoate (PHA) electrospinning wound dressing and a preparation method thereof, which effectively solves the problems of easy adhesion, poor biocompatibility and easy inflammation of existing wound dressings. The dressing is prepared by blending PHA with a hydrophilic polymer and an anti-inflammatory small molecule drug through electrospinning technology. It has multiple advantages such as absorbing exudate, slowly releasing drugs, good biocompatibility and hydrophobicity. It can not only avoid the risk of infection caused by accumulation of exudate, improve drug bioavailability, reduce toxic side effects, but also reduce the risk of secondary damage during dressing changes, while achieving the functions of sustained drug release, anti-inflammation, promoting cell proliferation and angiogenesis, and preventing adhesion of wound tissue, providing a highly efficient solution for wound repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a physical photo of the PHA / PVP / Cur electrospun wound dressing provided in Example 1 of the present application and a scanning electron microscope image of the surface morphology in a dry state and after being soaked in water and then freeze-dried.

[0029] Figure 2 This is a 72-hour drug release percentage curve of the PHA / PVP / Cur electrospinning wound dressing provided in Example 1 of the present application.

[0030] Figure 3 This is a diagram of the in vitro cellular antioxidant experiment of the PHA / PVP / Cur electrospun wound dressing provided in Example 1 of the present application.

[0031] Figure 4 This is the biocompatibility and live cell staining image of the PHA / PVP / Cur electrospinning wound dressing provided in Example 1 of the present application.

[0032] Figure 5 This is a surface optical contact angle measurement diagram of the PHA / PVP / Cur electrospun wound dressing provided in Example 1 of the present application.

[0033] Figure 6 This is a 72-hour drug release percentage curve of PHA / PVP / Cur electrospinning wound dressings with different ratios provided in Example 2 of the present application. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] The present invention will now be further described in conjunction with specific examples. The following examples are only intended to explain the present invention but do not limit the present invention. The test samples and test procedures used in the following examples include the following (if the specific experimental conditions are not specified in the examples, they are usually based on conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources).

[0037] Example 1

[0038] A method for preparing a polyhydroxyalkanoate electrospinning wound dressing comprises the following steps:

[0039] S1: PHA polymer, a hydrophilic polymer, and an anti-inflammatory small molecule drug were blended and dissolved in an organic solvent to obtain a PHA-containing mixed solution, wherein the concentrations of PHA and PVP were both 10% by weight, and the concentration of Cur was 0.1% by weight. The finished PHA polymer was purchased from Beijing PHAmily Microstructure Factory Biotechnology Co., Ltd.; the hydrophilic polymer was polyvinylpyrrolidone (PVP), and the anti-inflammatory small molecule drug was curcumin (Cur), purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0040] S2: The PHA-containing mixed solution obtained in step S1 was electrospun to obtain an electrospun film. The electrospinning method was as follows: the polymer solution was loaded into a 20 mL plastic syringe connected to an 18-gauge stainless steel needle, the nanofibers were collected using a release film, and electrospinning was performed for 10 hours at 25°C, 30% humidity, 25 kV voltage, a drum speed of 1000 rpm, a liquid feed rate of 1.5 mL / h, and a needle distance of 30 cm.

[0041] S3: The prepared PHA / PVP / Cur electrospun film was placed in a vacuum oven at 40°C and dried for 12 h to remove the organic solvent to obtain a PHA electrospun wound dressing.

[0042] In order to better illustrate the technical effects of the present application, the PHA electrospun wound dressing prepared in step S3 of Example 1 was subjected to surface morphology characterization, drug release analysis, in vitro cell antioxidant analysis, biocompatibility analysis, and optical contact angle analysis.

[0043] 1. Surface morphology characterization

[0044] The surface morphology of the PHA / PVP / Cur electrospun wound dressing samples after drying and soaking in deionized water at 37℃ for 4h and then freeze-dried were characterized by scanning electron microscopy (S-4800, 9.0kV). Figure 1 shown.

[0045] according to Figure 1 The dried PHA / PVP / Cur electrospun wound dressing exhibited uniform, micron-sized fibers, without droplets, indicating that the PHA, PVP, and Cur blend at this solute concentration could form a well-formed electrospun membrane under these electrospinning parameters. After soaking in water and then freeze-drying, the fibers on the dressing surface maintained a similarly uniform distribution as before soaking, indicating that deionized water immersion did not destroy the fiber morphology and that the dressing retained a fibrous membrane structure. The surface of the fibers after soaking in water became rougher than before treatment, indicating that the PVP in the fibers dissolved after absorbing water, forming pores on the fiber surface. This absorption of water simultaneously released the Cur drug contained in the dressing and increased the contact area between the dressing and the wound, facilitating cell attachment and growth and angiogenesis.

[0046] 2. Drug Release Analysis

[0047] The dried PHA / PVP / Cur electrospun wound dressing was soaked in a PBS-ethanol (10:1) mixed solution and placed on a 37°C constant temperature shaker. The extracts were sampled at fixed time points and the release concentration of Cur in the extracts was characterized using a UV-NIR spectrophotometer (Lambda950). The results were as follows: Figure 2 shown.

[0048] according to Figure 2 It can be seen that with the extension of immersion time, the cumulative release of Cur in the PHA / PVP / Cur electrospinning wound dressing reaches about 38% of the total drug loading after about 6 hours of rapid release, and then slowly releases. After 72 hours, the cumulative release reaches about 46% of the total drug loading, indicating that the anti-inflammatory small molecule drug Cur in the PHA / PVP / Cur electrospinning wound dressing can be slowly released.

[0049] 3. In vitro Cell Antioxidant Analysis

[0050] The PHA / PVP / Cur electrospun wound dressing was incubated with complete culture medium for 24 hours to obtain an extract. Subsequently, 100 μL of complete culture medium (negative group), complete culture medium containing 200 μM hydrogen peroxide (positive group), and extract containing 200 μM hydrogen peroxide (experimental group) were co-cultured with L929 mouse fibroblasts for 6 hours. The ROS fluorescent probe DCFH-DA was used to detect the ROS level in the cells, and the cell nuclei were stained with Hoechst. The morphological characteristics of the cells were examined using an inverted fluorescence microscope, and the results were as follows: Figure 3 shown.

[0051] according to Figure 3 Fluorescence images show that compared with the positive group, the level of intracellular reactive oxygen species in the experimental group is lower and similar to that in the negative group, indicating that the PHA / PVP / Cur electrospinning wound dressing has good anti-inflammatory properties.

[0052] 4. Biocompatibility Analysis

[0053] The PHA / PVP / Cur electrospun wound dressing was immersed in complete culture medium for 24 hours to obtain an extract. The PHA / PVP / Cur group used the extract, while the control group used complete culture medium to co-culture L929 mouse fibroblasts for 72 hours. The CCK-8 intensity of the extract was measured using a microplate reader to analyze cytotoxicity. Calcein-AM live cell fluorescent dye was used to analyze cell growth.

[0054] according to Figure 4It can be seen that after co-culture of PHA / PVP / Cur electrospun wound dressing with L929 cells for 72 hours, the PHA / PVP / Cur electrospun wound dressing had no obvious toxic effect on the cells compared with the control group, which indicates that the PHA / PVP / Cur electrospun wound dressing has good biocompatibility.

[0055] 5. Optical contact angle analysis

[0056] The surface water contact angle of the PHA / PVP / Cur electrospun wound dressing was measured using an optical contact angle analyzer (DSA 100) and was 133.5±1.7°, which indicated that the PHA / PVP / Cur electrospun wound dressing had good hydrophobicity and low adhesion to the wound tissue.

[0057] Example 2

[0058] On the basis of Example 1, the ratio of PHA, PVP and Cur was adjusted to explore the drug release ability of the spinning membrane under different mixing ratios.

[0059] S1. Dissolve the PHA polymer, hydrophilic high molecular polymer, and anti-inflammatory small molecule drug in an organic solvent to obtain a PHA-containing mixed solution, wherein the concentrations of PHA and PVP are:

[0060] Group A: PHA: 10%wt, PVP: 10%wt, Cur: 0.1%wt;

[0061] Group B: PHA: 10%wt, PVP: 10%wt, Cur: 0.2%wt;

[0062] Group C: PHA: 10%wt, PVP: 10%wt, Cur: 0.05%wt;

[0063] Group D: PHA: 8%wt, PVP: 12%wt, Cur: 0.1%wt;

[0064] Group E: PHA: 12%wt, PVP: 8%wt, Cur: 0.1%wt.

[0065] The finished PHA polymer was purchased from Beijing PHAmily Microstructure Factory Biotechnology Co., Ltd.; the hydrophilic polymer was polyvinylpyrrolidone (PVP), and the anti-inflammatory small molecule drug was curcumin (Cur), which was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0066] S2. Spinning the PHA-containing mixed solution obtained in step S1 by electrospinning technology, and collecting to obtain an electrospun film.

[0067] The specific method of electrospinning is as follows: the polymer solution is loaded into a plastic syringe (20 mL) connected to an 18-gauge stainless steel needle, the nanofibers are collected using a release film, and electrospinning is performed for 10 h at the following parameters: 25°C, 30% humidity, 25 kV voltage, 1000 r / min drum speed, 1.5 mL / h liquid supply rate, and 30 cm needle distance.

[0068] S3. The prepared PHA / PVP / Cur electrospun film was placed in a vacuum oven at 40°C and dried for 12 hours to remove the organic solvent, thereby obtaining a PHA electrospun wound dressing.

[0069] The PHA electrospinning wound dressing prepared in step S3 of the embodiment was subjected to drug release analysis. The results are as follows: Figure 6 As shown in the figure, under the same concentrations of PVP and PHA, the cumulative release percentage was the highest when the Cur concentration was 0.1% wt; under the same Cur concentration, the drug release percentage in the spinning dressing increased with the increase of PVP concentration.

[0070] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a polyhydroxyalkanoate (PHA) electrospinning wound dressing, characterized in that: The steps include: S1: dissolving a PHA polymer, a hydrophilic high molecular weight polymer, and an anti-inflammatory small molecule drug in an organic solvent to obtain a PHA-containing mixed solution; S2: using the PHA-containing mixed solution obtained in step S1 for electrospinning, and collecting to obtain an electrospun film; S3: Drying the electrospun film obtained in step S2 to remove the organic solvent to obtain a PHA electrospun wound dressing.

2. The preparation method according to claim 1, characterized in that In step S1, the concentration ratio of the PHA polymer, the hydrophilic high molecular polymer, and the anti-inflammatory small molecule drug is (80-120):(80-120):(0.5-2).

3. The preparation method according to claim 2, characterized in that The concentration of the PHA polymer in step S1 is 5 to 20% wt.

4. The preparation method according to any one of claims 1 to 3, characterized in that The PHA polymer described in step S1 includes one or more of PHB, P4HB, PHBV, P34HB, and PHBHHx.

5. The preparation method according to any one of claims 1 to 3, characterized in that The hydrophilic high molecular polymer in step S1 includes one or more of polyvinyl pyrrolidone, polyhydroxyethyl methyl methacrylate, polyacrylic acid or poly(polyethylene glycol methyl ether methacrylate).

6. The preparation method according to any one of claims 1 to 3, characterized in that The anti-inflammatory drug in step S1 includes one or more of curcumin, baicalin, paeoniflorin, and aloe extract.

7. The preparation method according to any one of claims 1 to 3, characterized in that The electrospinning parameters in step S2 are: temperature 15-25° C., humidity 20-35%, stainless steel needle 18-21 gauge, injection rate 0.5-2.5 mL / h, and voltage 18-28 kV.

8. A PHA electrospun wound dressing obtained by the preparation method according to any one of claims 1 to 6.

9. Use of the PHA electrospinning wound dressing according to claim 8 in wound repair.

10. The use according to claim 9, characterized in that The wound surface is located on the wall of the digestive tract.

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