Bacterial cellulose enhanced microneedle dressing and preparation method thereof

Abstract

The invention discloses a bacterial cellulose enhanced microneedle dressing and a preparation method thereof, and belongs to the field of biomedical materials. The preparation method of the microneedle dressing comprises the following steps: respectively preparing bacterial cellulose aerogel and a photocuring microneedle base material aqueous solution; transferring the light-cured microneedle base material aqueous solution into a microneedle mold, carrying out negative pressure bubble removal, and then carrying out ultraviolet light curing; putting the bacterial cellulose aerogel serving as a substrate into the microneedle mold, then transferring the photocuring microneedle base material solution into the microneedle mold, and performing ultraviolet curing after negative pressure defoaming to obtain the bacterial cellulose enhanced microneedle dressing. The bacterial cellulose aerogel is utilized to reinforce the microneedle substrate, so that the microneedle is endowed with excellent mechanical properties, flexibility and shape stability, and the clinical applicability of the microneedle dressing is improved.

Description

Technical Field

[0001] The present invention relates to the field of biomedical materials, and particularly to a bacterial cellulose-reinforced microneedle dressing and a preparation method thereof. Background Art

[0002] Compared with ordinary skin wounds, the biofilms and gangrene present on the surface of chronic infected wounds will prevent drugs lacking transdermal permeability released by traditional external drug delivery systems such as bacterial cellulose and hydrogels from reaching the treatment site, resulting in the local bioavailability of the drugs being lower than expected (Derakhshandeh H, et al. A wirelessly controlled smartbandage with 3D-printed miniaturized needle arrays. Advanced Functional Materials. 2020; 30: 1905544.). In recent years, the transdermal drug delivery system based on microneedles (MNs) has attracted extensive interest as an alternative to traditional drug delivery routes such as oral and parenteral administration. MNs generate micropores by physically penetrating the stratum corneum barrier, promoting the effective transport of therapeutic substances to the sub-dermis (Yang Y, et al. Recent advances in oral and transdermal protein delivery systems. Angewandte Chemie-International Edition. 2023; 62: e202214795.). However, the existing microneedles prepared by the molding method, whether they are methacrylated hyaluronic acid microneedles or methacrylated gelatin microneedles, have deficiencies such as poor flexibility and high brittleness, and can only produce small-sized microneedle patches. That is, it is impossible to obtain large-sized microneedle dressings that meet the clinical nursing needs of chronic diabetic foot wounds, nor can they be stored for a long time.

[0003] Bacterial cellulose (BC) is an animal nanocellulose biosynthesized by bacteria such as Acetobacter xylinum. It has a nanoporous network structure, and the fiber surface is rich in hydroxyl groups. It has good mechanical properties, flexibility, water absorption, moisture permeability, biocompatibility and immunogenicity, and has been widely used in the fields of wound dressings, artificial blood vessels, corneas, hard tissue repair materials, etc. (Zhou C, et al. De novo strategy with engineering a multifunctional bacterial cellulose-based dressing for rapid healing of infected wounds. Bioactive Materials. 2022;13:212-22.). In the previous work of the research group, polydopamine, bioactive glass, and bacitracin were successfully introduced into the nanoporous network structure of BC aerogel by the impregnation method (Ma L, et al. Homogeneous silver nanoparticle loaded polydopamine / polyethyleneimine-coated bacterial cellulose nanofibers for wound dressing. International Journal of Biological Macromolecules. 2023;246:125658), improving some defects existing in polydopamine coatings, bioactive glass, and bacitracin in the prior art. However, there are currently no relevant reports on improving the poor flexibility and brittleness of microneedles prepared by the molding method using BC aerogel. Summary of the Invention

[0004] The purpose of the present invention is to provide a bacterial cellulose-reinforced microneedle dressing and its preparation method to solve the problems existing in the above prior art. The microneedle dressing prepared by the combined use of bacterial cellulose aerogel and a photocurable microneedle substrate can significantly improve the mechanical properties, shape stability and flexibility of the microneedle dressing, and significantly improve the effect of skin wound healing.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides a preparation method of a bacterial cellulose-reinforced microneedle dressing, including the following steps:

[0007] Prepare bacterial cellulose aerogel and a photocurable microneedle substrate aqueous solution respectively;

[0008] Transfer the photocurable microneedle substrate aqueous solution into a microneedle mold, remove bubbles under negative pressure, and then carry out ultraviolet light curing;

[0009] Place the bacterial cellulose aerogel as a substrate into the microneedle mold, and then transfer the photocurable microneedle substrate solution into the microneedle mold. After removing air bubbles under negative pressure, perform ultraviolet light curing to obtain the bacterial cellulose-reinforced microneedle dressing.

[0010] Optionally, the aqueous photocurable microneedle substrate solution includes an aqueous solution of methacrylated gelatin and an aqueous solution of methacrylated hyaluronic acid.

[0011] Optionally, the concentration of the aqueous photocurable microneedle substrate solution is 3% - 7% w / v.

[0012] Optionally, the thickness of the bacterial cellulose aerogel is 1 - 3 mm.

[0013] Optionally, perform photocuring under ultraviolet light with a wavelength of 405 nm.

[0014] The present invention also provides a bacterial cellulose-reinforced microneedle dressing prepared by the described preparation method.

[0015] The present invention also provides the application of the described bacterial cellulose-reinforced microneedle dressing in the preparation of a skin wound healing functional dressing.

[0016] Optionally, the skin wound healing functional dressing includes a functional dressing for promoting the healing of diabetic ulcer wounds.

[0017] The present invention discloses the following technical effects:

[0018] The bacterial cellulose-reinforced microneedle dressing prepared by the present invention comprises a photocurable microneedle substrate and bacterial cellulose with a porous structure. This microneedle dressing mainly uses a bacterial cellulose aerogel with a 3D nanofiber network structure to reinforce the microneedle substrate, endowing the microneedle dressing with excellent mechanical properties, flexibility, and shape stability. While being able to obtain a microneedle dressing with better mechanical properties, the present invention can better adapt to the care of chronic wounds including diabetic ulcers, improving clinical applicability. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 Results of the shape stability experiment of the bacterial cellulose-reinforced methacrylated gelatin microneedle dressing in Example 1;

[0021] Figure 2 Results of the flexibility experiment of the bacterial cellulose reinforced methacrylated gelatin microneedle dressing in Example 1;

[0022] Figure 3 Results of the flexibility experiment of the bacterial cellulose reinforced methacrylated hyaluronic acid microneedle dressing in Example 4;

[0023] Figure 4 Effect of the bacterial cellulose reinforced methacrylated hyaluronic acid microneedle dressing loaded with copper-chlorogenic acid nanoparticles on nursing diabetic ulcer wounds in Example 7. Detailed implementation manners

[0024] The various exemplary implementation manners of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0026] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0027] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0028] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, that is, they are meant to include but not be limited to.

[0029] The present invention prepares a bacterial cellulose aerogel with a controllable thickness by using a film-liquid interface cultivation method and a freeze-drying method; prepares a microneedle tip by using a molding method; places the above-mentioned bacterial cellulose aerogel as a substrate enhancer into a mold; and prepares a microneedle dressing substrate by using a molding method to obtain the bacterial cellulose-reinforced microneedle dressing. The invention enhances the microneedle substrate with the bacterial cellulose aerogel, thereby endowing the microneedles with excellent mechanical properties, flexibility and shape stability, and improving the clinical applicability of the microneedle dressing. The above scheme and effects are further described below with specific examples.

[0030] The bacterial cellulose hydrogel and bacterial cellulose aerogel (BC) involved in the following examples were prepared according to the preparation method in the invention patent "CN113121872B A method for modifying bacterial cellulose by co-deposition coating of polydopamine / polyethyleneimine and its preparation method" to obtain a bacterial cellulose aerogel with the required thickness.

[0031] Example 1

[0032] Preparation method of bacterial cellulose-reinforced methacrylated gelatin microneedle dressing (BC / Gelma MN)

[0033] (1) Preparation of bacterial cellulose aerogel

[0034] Prepare a bacterial cellulose hydrogel by using a film-liquid interface cultivation method. After purification treatment, obtain an aerogel by using a freeze-drying method. The obtained bacterial cellulose aerogel has a thickness of 2 mm;

[0035] (2) Preparation of photocurable microneedle substrate aqueous solution

[0036] Prepare a 4% w / v methacrylated gelatin solution;

[0037] (3) Preparation of microneedle dressing tip by using a molding method

[0038] Transfer the solution prepared in step (2) into a silicone mold, remove bubbles by using negative pressure, concentrate the solution to a viscous state in a vacuum drying oven, and perform photocuring by using ultraviolet light with a wavelength of 405 nm;

[0039] (4) Place the bacterial cellulose aerogel obtained in step (1) as a substrate into the mold;

[0040] (5) Preparation of microneedle dressing substrate by using a molding method

[0041] Transfer the solution prepared in step (2) into a silicone mold, remove bubbles by using negative pressure, concentrate the solution to a viscous state in a vacuum drying oven, and perform photocuring by using ultraviolet light with a wavelength of 405 nm to obtain a bacterial cellulose-reinforced methacrylated gelatin microneedle dressing.

[0042] Referring to the above steps, methylacrylated gelatin micro - needles (GelmaMN) were prepared by the molding method without adding BC aerogel as a control group. The shape stability and flexibility of the micro - needle dressings prepared in Example 1 and the control group were investigated.

[0043] Figure 1 It is a photo of the experimental results of the shape stability of the bacterial cellulose - reinforced methylacrylated gelatin micro - needle dressing. As can be seen from the figure, after being placed at room temperature for 6 h, Gelma MN curled up, which may be due to the deformation caused by the dehydration of the micro - needle hydrogel. Under the action of BC aerogel, the shape of BC / Gelma MN was well maintained.

[0044] Figure 2 It is a photo of the experimental results of the flexibility of the bacterial cellulose - reinforced methylacrylated gelatin micro - needle dressing. As can be seen from the figure, BC / Gelma MN has excellent flexibility and can be bent arbitrarily without breaking; while Gelma MN is more brittle and cracks easily when bent.

[0045] Example 2

[0046] The difference from Example 1 is that the concentration of the methylacrylated gelatin solution is 3% w / v, and other method steps are the same as in Example 1.

[0047] At the same time, the micro - needle dressing prepared without adding BC aerogel was used as a control group. The results were the same as in Example 1. The micro - needle dressing prepared in Example 2 had better shape stability and flexibility than the control group.

[0048] Example 3

[0049] The difference from Example 1 is that the concentration of the methylacrylated gelatin solution is 7% w / v, and other method steps are the same as in Example 1.

[0050] At the same time, the micro - needle dressing prepared without adding BC aerogel was used as a control group. The results were the same as in Example 1. The micro - needle dressing prepared in Example 3 had better shape stability and flexibility than the control group.

[0051] Example 4

[0052] Preparation method of bacterial cellulose - reinforced methylacrylated hyaluronic acid micro - needle dressing (BC / HAMAMN)

[0053] (1) Preparation of bacterial cellulose aerogel

[0054] Bacterial cellulose hydrogel was prepared by the film - liquid interface culture method. After purification, the aerogel was obtained by freeze - drying method. The thickness of the obtained bacterial cellulose aerogel was 3 mm;

[0055] (2) Preparation of the aqueous solution of the photocurable micro - needle substrate

[0056] Prepare a 5% w / v methacrylated hyaluronic acid solution;

[0057] (3) Prepare the tip of the microneedle dressing using the molding method

[0058] Transfer the solution prepared in step (2) into a silicone mold, remove air bubbles using negative pressure, concentrate the solution to a viscous state in a vacuum drying oven, and perform photocuring using ultraviolet light at 405 nm.

[0059] (4) Place the bacterial cellulose aerogel obtained in step (1) as a substrate into a mold;

[0060] (5) Prepare the substrate of the microneedle dressing using the molding method

[0061] Transfer the solution prepared in step (2) into a silicone mold, remove air bubbles using negative pressure, concentrate the solution to a viscous state in a vacuum drying oven, and perform photocuring using ultraviolet light at 405 nm to obtain a bacterial cellulose-reinforced methacrylated hyaluronic acid microneedle dressing.

[0062] Refer to the above method, prepare a methacrylated hyaluronic acid microneedle dressing (HAMAMN) using the molding method without adding BC aerogel as a control group. Examine the flexibility of the microneedle dressings prepared in Example 1 and the control group.

[0063] Figure 3 This is a photo of the experimental results of the flexibility of the bacterial cellulose-reinforced methacrylated hyaluronic acid microneedle dressing. As can be seen from the figure, BC / HAMAMN has excellent flexibility and can be bent arbitrarily without breaking; while HAMAMN is more brittle and prone to breakage when bent.

[0064] Example 5

[0065] The difference from Example 4 is that the concentration of the methacrylated hyaluronic acid solution is 3% w / v, and the other method steps are the same as in Example 4.

[0066] At the same time, use the microneedle dressing prepared without adding BC aerogel as a control group. The results are the same as in Example 4, and the microneedle dressing prepared in Example 5 has better flexibility than the control group.

[0067] Example 6

[0068] The difference from Example 4 is that the concentration of the methacrylated hyaluronic acid solution is 7% w / v, and the other method steps are the same as in Example 4.

[0069] At the same time, use the microneedle dressing prepared without adding BC aerogel as a control group. The results are the same as in Example 4, and the microneedle dressing prepared in Example 6 has better shape stability and flexibility than the control group.

[0070] Application of Bacterial Cellulose Reinforced Microneedle Dressing in Example 7

[0071] Copper chloride solution and chlorogenic acid solution were mixed. After complexation reaction and freeze-drying, copper-chlorogenic acid complex nanoparticles (Cu-CA) were obtained. The Cu-CA nanoparticles were loaded into HAMA MN and BC / HAMA MN to obtain Cu-CA@HAMAMN functional dressing and Cu-CA@BC / HAMAMN functional dressing. The effects of the functional dressings on treating the infected wounds of full-thickness skin injury on the backs of type II diabetic rats were investigated, as well as the synergistic effect brought by the BC-enhanced substrate.

[0072] Figure 4 For the effect of Cu-CA@BC / HAMAMN functional dressing on nursing diabetic ulcer wounds. As can be seen from the figure, compared with HAMA MN and commercial antibacterial dressings The Cu-CA@HAMAMN functional dressing has a significant effect on promoting the healing of infected wounds; while the wound healing promotion effect of the Cu-CA@BC / HAMA MN functional dressing is better than that of the Cu-CA@HAMAMN functional dressing. This is the gain effect brought by the BC-enhanced substrate.

[0073] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A preparation method of a bacterial cellulose reinforced microneedle dressing, characterized in that It includes the following steps: Prepare bacterial cellulose aerogel and aqueous solution of photocurable microneedle substrate respectively; Transfer the aqueous solution of the photocurable microneedle substrate into a microneedle mold, remove bubbles under negative pressure, and then carry out ultraviolet curing; Place the bacterial cellulose aerogel as a substrate into the microneedle mold, then transfer the aqueous solution of the photocurable microneedle substrate into the microneedle mold, remove bubbles under negative pressure and then carry out ultraviolet curing to obtain the bacterial cellulose-reinforced microneedle dressing.

2. The preparation method according to claim 1, characterized in that, The aqueous solution of the photocurable microneedle substrate includes aqueous solution of methacrylated gelatin and aqueous solution of methacrylated hyaluronic acid.

3. The preparation method according to claim 1, characterized in that, The concentration of the aqueous solution of the photocurable microneedle substrate is 3% - 7% w / v.

4. The preparation method according to claim 1, characterized in that, The thickness of the bacterial cellulose aerogel is 1 - 3 mm.

5. The preparation method according to claim 1, characterized in that, Photocuring is carried out under ultraviolet light with a wavelength of 405 nm.

6. A bacterial cellulose reinforced microneedle dressing, characterized in that, It is prepared by the preparation method according to any one of claims 1 - 5.

7. Use of the bacterial cellulose-reinforced microneedle dressing according to claim 6 in the preparation of a skin wound healing functional dressing.

8. The application according to claim 7, characterized in that, The skin wound healing functional dressing includes a functional dressing for promoting the healing of diabetic ulcer wounds.

Images