Multilayer structural color hydrogel microneedle patch containing melanin as well as preparation method and application of hydrogel microneedle patch

Abstract

The invention discloses a melanin-containing multi-layer structural color hydrogel microneedle patch and a preparation method and application thereof.The preparation method comprises the steps that a colloidal particle solution is injected into a microneedle mold, and a colloidal crystal microneedle template is obtained through a deposition method; preparing a hydrogel pre-polymerization solution from melanin and a high-molecular organic matter pre-polymerization solution, injecting the hydrogel pre-polymerization solution into a microneedle mold containing a colloidal crystal microneedle template, and curing the hydrogel pre-polymerization solution to obtain a colloidal crystal hydrogel mixed microneedle patch; after the colloidal crystal microneedle template is removed, the inverse opal structure hydrogel scaffold containing melanin is obtained; preparing a pre-gel solution of a drug-added temperature-sensitive polymer material, pouring the pre-gel solution into holes of the prepared inverse opal structure hydrogel stent, and cooling and curing to form a shell layer, thereby obtaining the hydrogel stent. The hydrogel microneedle patch provided by the invention contains an inverse opal structure bracket with photo-thermal conversion capacity and inherent immunoregulation performance and a temperature-sensitive gel outer layer loaded with drug components, and integrates multiple functions of photo-thermal response, drug release, immunoregulation, sensing and the like.

Description

Technical Field

[0001] The present invention belongs to the field of biomaterials, and particularly relates to a multi-layered structural color hydrogel microneedle patch containing melanin, a preparation method thereof, and applications in wound treatment and scar repair. Background Art

[0002] The wound healing process generally includes four overlapping physiological stages: blood coagulation, inflammation, proliferation, and remodeling. In the research topic of wound repair, hydrogel patches have been widely used due to their properties such as keeping the wound moist, alleviating pain, and effectively delivering drugs. Among them, hydrogel microneedle patches have become powerful transdermal drug delivery tools due to their unique skin barrier puncture ability. Although existing hydrogel microneedle patches have made great progress, their structural functions are relatively single and the drug release behavior is relatively simple. The therapeutic effect often disappears after one or two stages, and they cannot effectively target the characteristics of each stage of the wound surface and hierarchically deliver drugs to promote wound healing.

[0003] Compared with traditional patch materials, emerging patches with a multi-layered structure are more complex and diverse in terms of structural composition or material selection, and can integrate functions such as self-adhesion, antibacterial, moisturizing, and drug controlled release to enhance the effect of wound repair. On the other hand, inverse opal structure hydrogels are gel materials obtained by replicating the structure of colloidal crystal templates. The surface of inverse opal structure hydrogels has interconnected pores, and this pore structure greatly expands the specific surface area of the gel, providing an excellent site for drug loading. Therefore, inverse opal hydrogels have been widely studied for applications in the field of drug delivery. Summary of the Invention

[0004] Object of the Invention: The technical problem to be solved by the present invention is to provide a multi-layered structural color hydrogel microneedle patch containing melanin and a preparation method thereof, aiming at the single structure of existing hydrogel patches, lack of sensing ability and therapeutic effect.

[0005] In order to achieve the above object of the invention, the technical solution adopted by the present invention is as follows: A preparation method of a multi-layered structural color hydrogel microneedle patch containing melanin, comprising the following steps: (1) Inject a colloidal particle solution into a microneedle mold, and obtain a colloidal crystal microneedle template by the deposition method; (2) Prepare a hydrogel prepolymer solution by mixing melanin and a prepolymer solution of a high molecular organic substance, and inject it into the microneedle mold containing the colloidal crystal microneedle template. After curing the hydrogel prepolymer solution, obtain a colloidal crystal hydrogel hybrid microneedle patch; (3) After removing the colloidal crystal microneedle template, obtain an inverse opal structure hydrogel scaffold containing melanin; (4) Prepare a pre-gel solution of a temperature-sensitive polymer material added with a drug, and pour it into the pores of the inverse opal-structured hydrogel scaffold prepared in step (3). After cooling and solidifying, a shell layer is formed, thus obtaining the product.

[0006] Specifically, in step (1), the colloidal particle solution is a silica nanoparticle alcohol suspension with a mass-volume concentration of 3%-4% (w / v, g / mL); the deposition method conditions are to stand still at 20-25 °C for 4-6 hours.

[0007] Specifically, in step (2), the melanin is any one of melanin nanoparticles, graphene oxide, black phosphorus nanosheets, and carbon nanotubes; the prepolymer solution of the high molecular organic matter is a mixture of heparin-modified methacrylated hyaluronic acid (Hep-HAMA), polyethylene glycol diacrylate (PEGDA), and a photoinitiator (preferably HMPP).

[0008] Specifically, in the hydrogel prepolymer solution obtained in step (2), the mass-volume concentration of methacrylated hyaluronic acid is 1%-5% (w / v), the volume concentration of polyethylene glycol diacrylate is 10%-20% (v / v), the volume concentration of the photoinitiator is 1%-2% (v / v), and the concentration of melanin is 1-5 mg / mL.

[0009] Specifically, in step (2), the curing is carried out by irradiating with an ultraviolet lamp for 30 seconds to 3 minutes.

[0010] Specifically, in step (3), soak in a 5%-10% hydrofluoric acid aqueous solution for 12-24 h to remove the colloidal crystal microneedle template.

[0011] Specifically, in step (4), the drug is selected from any one of growth factors promoting wound healing including vascular endothelial growth factor and epidermal growth factor, verteporfin, puerarin of traditional Chinese medicine, and extracellular vesicles, and its mass concentration in the pre-gel solution is 1%-3%.

[0012] Specifically, in step (4), the temperature-sensitive polymer material is selected from one or a mixture of two or more of agarose (LAG), low melting point agarose (Gel), gelatin, pectin, carrageenan, and xanthan gum.

[0013] Furthermore, the multilayer structural color hydrogel microneedle patch containing melanin prepared by the above preparation method is also within the protection scope of the present invention.

[0014] Furthermore, the present invention also claims the application of the above multilayer structural color hydrogel microneedle patch containing melanin in the preparation of drugs for wound treatment or scar repair.

[0015] Compared with the prior art, the present invention has the following advantages: (1) The present invention prepares a microneedle array with a microneedle mold. The preparation method has programmable function regulation, is simple, convenient to operate, inexpensive, does not require high technical requirements, and is easy to control the morphology and structural color of the microneedle array. The prepared multi-layer structured color hydrogel microneedle patch containing melanin has ideal mechanical strength and a large number of periodically arranged pore structures. The periodically arranged pore structures can provide sufficient space for drug loading, and at the same time endow the microneedle patch with structural color. The structural color and its reflection wavelength change with drug loading and release, enabling the microneedle patch to have the ability to monitor drug release. Under infrared irradiation, melanin causes the temperature of the patch to rise, triggering the degradation of the outer shell layer thermosensitive hydrogel and the release of the encapsulated drug components. After the outer layer gel degrades, the exposed microneedle core scaffold can play a further immunomodulatory role. At the same time, these characteristics enable the multi-layer structured color hydrogel microneedle patch containing melanin to overcome the limitations of traditional wound treatment hydrogel systems.

[0016] (2) The multi-layer structured color hydrogel microneedle patch containing melanin prepared by the present invention contains an inverse opal structure scaffold with photothermal conversion ability and innate immunomodulatory properties and a thermosensitive gel outer layer loaded with drug components, integrating multiple functions such as photothermal response, drug release, immunomodulation, and sensing.

[0017] (3) The microneedle patch prepared by the present invention can be used for the treatment of difficult-to-heal wounds, promote wound healing, and prevent scarring. Description of the Drawings

[0018] The following further specific description of the present invention is made in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0019] Figure 1 It is a schematic diagram of the preparation process of the multi-layer structured color hydrogel microneedle patch containing melanin of the present invention.

[0020] Figure 2 It is a scanning electron microscope image of the multi-layer microneedle patch obtained in Example 1.

[0021] Figure 3 It is a physical diagram of the microneedle patch obtained in Example 1.

[0022] Figure 4 It is a spectral characterization diagram of the color change of the microneedle patch before and after the degradation of the outer shell layer obtained in Example 1. Detailed Description of the Invention

[0023] The present invention can be better understood according to the following examples. Example 1

[0024] Combined Figure 1 As shown, it is a schematic diagram of the preparation process of the multi-layer structural color hydrogel microneedle patch containing melanin of the present invention. In the figure, A is the self-assembly of colloidal crystals to form a colloidal crystal microneedle template, and B in the figure is to fill the pre-gel solution into the colloidal crystal microneedle template; C in the figure is to remove the template after ultraviolet curing to obtain a microneedle support layer with an inverse opal structure; D in the figure is to add the pre-gel solution of the filler layer into the pores of the support layer, and cool to form a gel to finally obtain a multi-layer structural color hydrogel microneedle patch containing melanin; among them, 1 is silica nanoparticles, 2 is a PDMS microneedle mold, 3 is a gel containing melanin for constructing the microneedle support, and 4 is a thermosensitive gel containing drugs for constructing the outer shell layer.

[0025] When preparing the colloidal crystal microneedle template, prepare a 3% alcohol suspension of silica nanoparticles, and add an appropriate amount into the microneedle mold. Remove air bubbles by suction. Place the microneedle mold at a constant temperature of 25 °C for 4 hours. During the evaporation of alcohol, the silica nanoparticles self-assemble into colloidal crystals inside the microneedle mold. The second step is the preparation of the inverse opal microneedle support containing melanin. The pre-gel solution consists of 2% (w / v) Hep-HAMA, 15% (v / v) PEGDA, 5 mg / mL black phosphorus nanosheets, and 1% (v / v) HMPP. Add the pre-gel solution into the microneedle mold containing the colloidal crystal microneedle template. Place the mold until there are no air bubbles, and cure with ultraviolet light for 3 minutes. After removing the colloidal crystal microneedle template by hydrofluoric acid, an inverse opal microneedle support containing melanin is obtained. The third step is to prepare a pre-gel solution of a thermosensitive polymer material added with drugs. The pre-gel solution consists of 10% (w / v) gelatin heated, 1% (w / v) agarose, and 2 μg / mL verteporfin. Finally, pour the pre-gel solution into the pores of the inverse opal support and cool to obtain the final multi-layer microneedle patch.

[0026] Figure 2 It is a scanning electron microscope image of the multi-layer microneedle patch prepared in the example. Among them, i is the cross-section of the multi-layer microneedle patch. The inside of this cross-section is a gel solid structure, and the outer shell layer is a porous structure filled with gel; ii is an enlarged view of the cross-section of the outer shell layer of the multi-layer microneedle patch shown in i, iii is an enlarged view of the pore structure of the outer shell layer shown in ii, and iv is the cross-section of the inverse opal support exposed after the gel filled in the outer shell layer degrades.

[0027] Figure 3 It is a physical picture of the microneedle patch obtained in this example and a scanning electron microscope image of a single needle.

[0028] Figure 4It is the spectral characterization diagram of the color change of the microneedle patch before and after the degradation of the outer shell layer in this embodiment, showing the structural color change of the multilayer microneedle patch after the filling gel of the outer shell layer degrades. Among them, 1 and 2 are the spectra before degradation, and 3 and 4 are the spectra after degradation. Example 2

[0029] When preparing the colloidal crystal microneedle template, prepare a 3% alcoholic suspension of silica nanoparticles and add an appropriate amount to the microneedle mold. Remove air bubbles by suction. Place the microneedle mold at a constant temperature of 25 °C for 4 hours. During the evaporation of alcohol, the silica nanoparticles self-assemble into colloidal crystals inside the microneedle mold. The second step is the preparation of the melanin-containing inverse opal microneedle scaffold. The pre-gel solution consists of 5% (w / v) Hep-HAMA, 10% (v / v) PEGDA, 5 mg / mL black phosphorus nanosheets, and 1% (v / v) HMPP. Add the pre-gel solution to the microneedle mold containing the colloidal crystal microneedle template. Place the mold until there are no air bubbles and cure it with ultraviolet light for 3 minutes. After removing the colloidal crystal microneedle template by hydrofluoric acid, a melanin-containing inverse opal microneedle scaffold is obtained. The third step is to prepare a pre-gel solution of a temperature-sensitive polymer material added with drugs. The pre-gel solution consists of heated 10% (w / v) gelatin, 1% (w / v) agarose, and 3% (w / v) puerarin. Finally, pour the pre-gel solution into the pores of the inverse opal scaffold and cool to obtain the final multilayer microneedle patch. Example 3

[0030] When preparing the colloidal crystal microneedle template, prepare a 3% alcoholic suspension of silica nanoparticles and add an appropriate amount to the microneedle mold. Remove air bubbles by suction. Place the microneedle mold at a constant temperature of 25 °C for 4 hours. During the evaporation of alcohol, the silica nanoparticles self-assemble into colloidal crystals inside the microneedle mold. The second step is the preparation of the melanin-containing inverse opal microneedle scaffold. The pre-gel solution consists of 2% (w / v) Hep-HAMA, 15% (v / v) PEGDA, 1 mg / mL melanin nanoparticles, and 1% (v / v) HMPP. Add the pre-gel solution to the microneedle mold containing the colloidal crystal microneedle template. Place the mold until there are no air bubbles and cure it with ultraviolet light for 3 minutes. After removing the colloidal crystal microneedle template by hydrofluoric acid, a melanin-containing inverse opal microneedle scaffold is obtained. The third step is to prepare a pre-gel solution of a temperature-sensitive polymer material added with drugs. The pre-gel solution consists of heated 2% (w / v) low melting point agarose and 2 μg / mL verteporfin. Finally, pour the pre-gel solution into the pores of the inverse opal scaffold and cool to obtain the final multilayer microneedle patch. Example 4

[0031] Example of application effect Two circular skin incisions with a diameter of 1 cm were made on the back of diabetic SD rats. A bacterial suspension was applied to the wounds to induce infection. The patch prepared in Example 1 was placed on the wounds, and near-infrared light irradiation (0.8 W / cm²) for 10 minutes was used to induce the degradation of the outer shell layer filling gel. Then, irradiation with 690 nm light (25 mW / cm²) for 10 minutes was used to induce the photodynamic antibacterial effect of verteporfin. This treatment continued for three days, once a day. After that, wound photos were taken on days 0, 3, 6, 9, and 12, respectively. The healed wounds were collected on day 12. Histological evaluation found that compared with the wound healing of the control group that did not receive treatment, the wound area of the rats treated with the patch showed a faster healing rate, specifically manifested as having a lower inflammation level, more collagen deposition, and the generation of a relatively complete epidermis and skin appendages.

[0032] The present invention provides an idea and method for a multilayer structural color hydrogel microneedle patch containing melanin, its preparation method and application. There are many methods and ways to specifically implement this technical solution. The above is only the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by existing technologies.

Claims

1. A preparation method of a multilayer structural color hydrogel microneedle patch containing melanin, characterized in that, It includes the following steps: (1) Inject the colloidal particle solution into the microneedle mold, and use the deposition method to obtain a colloidal crystal microneedle template; (2) Prepare a hydrogel prepolymer solution by mixing melanin with a prepolymer solution of a high molecular organic compound, and inject it into the microneedle mold containing the colloidal crystal microneedle template. After curing the hydrogel prepolymer solution, a colloidal crystal hydrogel hybrid microneedle patch is obtained; (3) After removing the colloidal crystal microneedle template, an inverse opal-structured hydrogel scaffold containing melanin is obtained; (4) Prepare a pregel solution of a temperature-sensitive polymer material added with a drug, and pour it into the pores of the inverse opal-structured hydrogel scaffold prepared in step (3). After cooling and curing, a shell layer is formed, thus obtaining the product.

2. The preparation method of the melanin-containing multilayer structural color hydrogel microneedle patch according to claim 1, characterized in that, In step (1), the colloidal particle solution is a silica nanoparticle alcohol suspension with a mass-volume concentration of 3%-4%; the deposition method conditions are to stand still at 20-25 °C for 4-6 hours.

3. The preparation method of the melanin-containing multi-layer structural color hydrogel microneedle patch according to claim 1, characterized in that, In step (2), the melanin is any one of melanin nanoparticles, graphene oxide, black phosphorus nanosheets, and carbon nanotubes; the prepolymer solution of the high molecular organic compound is a mixture of heparin-modified methacrylated hyaluronic acid, polyethylene glycol diacrylate, and a photoinitiator.

4. The preparation method of the melanin-containing multi-layer structural color hydrogel microneedle patch according to claim 3, characterized in that, In step (2), in the obtained hydrogel prepolymer solution, the mass-volume concentration of methacrylated hyaluronic acid is 1%-5%, the volume concentration of polyethylene glycol diacrylate is 10%-20%, the volume concentration of the photoinitiator is 1%-2%, and the concentration of melanin is 1-5 mg / mL.

5. The preparation method of the multilayer structural color hydrogel microneedle patch containing melanin according to claim 3, characterized in that, In step (2), the curing is carried out by irradiating with an ultraviolet lamp for 30 seconds to 3 minutes.

6. The preparation method of the multilayer structural color hydrogel microneedle patch containing melanin according to claim 3, characterized in that, In step (3), soak it in a 5%-10% hydrofluoric acid aqueous solution for 12-24 h to remove the colloidal crystal microneedle template.

7. The preparation method of the melanin-containing multi-layer structural color hydrogel microneedle patch according to claim 3, characterized in that, In step (4), the drug is selected from any one of growth factors promoting wound healing including vascular endothelial growth factor and epidermal growth factor, verteporfin, puerarin of traditional Chinese medicine, and extracellular vesicles, and its mass concentration in the pregel solution is 1%-3%.

8. The preparation method of the melanin-containing multi-layer structural color hydrogel microneedle patch according to claim 3, characterized in that, In step (4), the temperature-sensitive polymer material is selected from one or a mixture of two or more of agarose, low melting point agarose, gelatin, pectin, carrageenan, and xanthan gum.

9. A multi-layer structural color hydrogel microneedle patch containing melanin prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the multi-layer structural color hydrogel microneedle patch containing melanin according to claim 9 in the preparation of a drug for wound treatment or scar repair.

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