Microneedle female die loaded with metal organic aerogel stent as well as preparation method and application of microneedle female die

Abstract

The invention belongs to the field of biomedical materials, and particularly relates to a microneedle female die loaded with a metal organic aerogel support and a preparation method and application of the microneedle female die. The preparation method comprises the following steps: preparing metal organic hydrogel, filling the metal organic hydrogel into holes of a micro-needle female die, and freeze-drying to prepare the micro-needle female die loaded with the metal organic aerogel bracket. The preparation method provided by the invention has the advantages of simplicity and convenience in operation, high adaptability, convenience in industrial batch production and the like, and the prepared micro-needle female die can improve the preparation efficiency of the polymer micro-needle, avoids complex centrifugal or vacuum operation in the subsequent micro-needle preparation process, and is an effective way for promoting commercialized application of the micro-needle.

Description

Technical Field

[0001] The invention belongs to the field of biomedical materials, and in particular relates to a microneedle negative mold loaded with a metal organic aerogel support, and a preparation method and application thereof. Background Art

[0002] my country attaches great importance to the research and development and application of biopharmaceutical materials. In the field of transdermal drug delivery technology, it has become a research hotspot in the field of drug delivery because of its minimally invasive, convenient and high patient compliance. Microneedles are a new type of transdermal drug delivery carrier with a short needle tip length of micrometer level. When the microneedles pierce into the skin, they will not touch the patient's nerve endings and cause pain. The channels formed in the skin can improve the transdermal absorption efficiency of drugs and reduce the side effects of long-term residual drugs. It has received widespread attention in recent years.

[0003] Existing microneedle preparation technologies include micromolding, photolithography, micro-electromechanical systems, electroforming and 3D printing. Among them, polymer microneedles prepared by micromolding technology are favored by people because they can use a single microneedle master template to replicate a large number of microneedle negative molds. In addition, micromolding technology can accurately control the geometry of microneedles, facilitate drug delivery, and has the potential for large-scale industrial production. The most commonly used microneedle negative mold in the laboratory is the polydimethylsiloxane (PDMS) mold. The mold prepared by PDMS shows good biocompatibility and good air permeability for a variety of cell types, and can be reused many times, so it is widely used in the preparation of polymer microneedles.

[0004] When using a microneedle negative mold, especially a PDMS microneedle negative mold, to prepare polymer microneedles, it is difficult to completely fill the holes in the microneedle negative mold with polymer gel material due to the micron-scale size of the holes. Generally, complex operations such as centrifugation or vacuum need to be introduced during the microneedle preparation process, which limits the commercial application of polymer microneedles prepared by micromolding technology. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a microneedle negative mold loaded with metal organic aerogel as a scaffold, and the metal organic hydrogel in the polydimethylsiloxane (PDMS) microneedle negative mold is freeze-dried to prepare a microneedle negative mold containing an aerogel scaffold. The preparation method provided by the present invention has the advantages of simple operation, high adaptability, and convenience for industrial batch production. The prepared microneedle negative mold can improve the preparation efficiency of polymer microneedles, avoid the complex operation of centrifugation or vacuum in the subsequent microneedle preparation process, and is an effective way to promote the commercial application of microneedles.

[0006] The technical solution of the present invention is specifically as follows.

[0007] In a first aspect, the present invention provides a microneedle negative mold loaded with a metal organic aerogel scaffold, wherein the metal organic aerogel scaffold is loaded in micrometer-sized pores of the microneedle negative mold.

[0008] Furthermore, the metal organic aerogel scaffold is obtained by freeze-drying a metal organic hydrogel formed by coordination interaction between metal and imidazole dicarboxylic acid in the pores.

[0009] Furthermore, the metal is cobalt.

[0010] Furthermore, the coordination interaction includes the coordination interaction between metal and N and / or the coordination interaction between metal and O.

[0011] As used herein, a microneedle negative mold is a mold used to manufacture a microneedle array, which is a "negative mold" for manufacturing microneedles, that is, its shape and structure are the reverse model of the microneedles, and the microneedle array can be replicated by a transfer process.

[0012] The negative mold of the microneedle can be made of a variety of materials, and commonly used materials include silicon, metals (such as nickel, copper, etc.), polydimethylsiloxane (PDMS), photosensitive resins (such as SU-8), polymer materials (such as PLA, PCL), etc.

[0013] Furthermore, the microneedle negative mold is a polydimethylsiloxane (PDMS) microneedle negative mold.

[0014] Furthermore, the micron-scale holes of the microneedle negative mold are hole arrays, and the radius of the holes is 100-400 μm and the length is 400-1000 μm.

[0015] The negative mold of the microneedle can be prepared by any conventional method well known in the art, including but not limited to photolithography, deep reactive ion etching, electroforming, soft mold method (making a negative mold by replicating a flexible material (such as PDMS) on a hard mold, for example, as used in the embodiments of this article to prepare a blank PDMS microneedle negative mold by stainless steel microneedles), hot pressing, etc.

[0016] In a second aspect, the present invention provides a method for preparing a negative mold of a microneedle loaded with a metal organic aerogel scaffold as described herein, comprising the following steps:

[0017] (1) reacting a metal salt with imidazole dicarboxylic acid in an organic solvent under alkaline conditions, collecting the precipitate produced by the reaction by centrifugation, dispersing it in deionized water after washing, and allowing it to stand for 24-72 hours to form a metal organic hydrogel;

[0018] (2) Filling the obtained metal organic hydrogel into the micron-sized pores of the microneedle negative mold, removing the excess metal organic hydrogel outside the pores, and then fully volatilizing the water in the metal organic hydrogel by freeze drying, so that the metal organic hydrogel in the pores of the microneedle negative mold is transformed into a metal organic aerogel scaffold.

[0019] Furthermore, the metal salt is a cobalt salt, including cobalt chloride, cobalt formate, cobalt sulfate, cobalt acetate, cobalt citrate, cobalt nitrate or cobalt carbonate.

[0020] Furthermore, the organic solvent is ethanol or methanol.

[0021] Furthermore, step (1) comprises first dissolving the metal salt and the imidazole dicarboxylic acid in an organic solvent respectively, and then mixing them to react.

[0022] Further, in an embodiment where the metal salt and the imidazole dicarboxylic acid are each dissolved in an organic solvent and then mixed to perform the reaction, the molar concentration of the metal ion in the organic solvent is 10-200 mmol / L.

[0023] Further, in an embodiment where the metal salt and the imidazole dicarboxylic acid are each dissolved in an organic solvent and then mixed to perform the reaction, the molar concentration of the imidazole dicarboxylic acid in the organic solvent is 100-300 mmol / L.

[0024] The reaction comprises stirring the reaction at room temperature for 1.5-2 hours.

[0025] Furthermore, the alkaline condition is maintained by adding triethanolamine and Tris-HCl buffer.

[0026] Furthermore, the pH value of the Tris-HCl buffer is 8.0-9.0.

[0027] Further, in the embodiment where the metal salt and the imidazole dicarboxylic acid are each dissolved in an organic solvent and then mixed to react, the volume fraction of the triethanolamine in the imidazole dicarboxylic acid solution is 5%-20%.

[0028] Further, in the embodiment where the metal salt and the imidazole dicarboxylic acid are each dissolved in an organic solvent and then mixed to react, the volume fraction of the Tris-HCl buffer in the imidazole dicarboxylic acid solution is 10%-40%.

[0029] Furthermore, in step (2), the metal organic hydrogel is filled into the micrometer-sized pores of the microneedle negative membrane by vacuum degassing.

[0030] Furthermore, the vacuum degassing method comprises the following steps: subjecting a sufficient amount of the metal organic hydrogel to vacuum treatment 2-3 times to fully fill the holes of the microneedle negative mold, and each vacuum treatment lasts for 3-5 minutes.

[0031] Furthermore, the freeze-drying method includes storing the microneedle negative mold filled with the metal organic hydrogel at -80°C for 12-48 hours, and then using a freeze dryer for freeze drying for 18-48 hours.

[0032] Furthermore, the washing includes washing the precipitate collected by centrifugation with ethanol, and repeating the centrifugation washing 3-5 times.

[0033] Further, the precipitate was dispersed in 0.5-2 mL of deionized water after washing.

[0034] In a third aspect, the present invention provides a use of a metal organic aerogel scaffold-loaded microneedle negative mold as described herein or a metal organic aerogel scaffold-loaded microneedle negative mold prepared by the preparation method described herein for preparing polymer microneedles without centrifugation or vacuum treatment.

[0035] In a fourth aspect, the present invention provides a polymer microneedle prepared by the negative mold of the microneedle loaded with a metal organic aerogel scaffold as described herein or the negative mold of the microneedle loaded with a metal organic aerogel scaffold prepared by the preparation method described herein.

[0036] The method for preparing microneedles by a microneedle negative mold can be any method known in the art for transferring a suitable microneedle raw material to the surface of the negative mold, such as injecting the microneedle raw material (such as a polymer material) into the microneedle negative mold or casting it onto the surface of the microneedle negative mold, and then curing it after standing to form a microneedle array.

[0037] Furthermore, the polymer microneedle may be a polyethylene glycol diacrylate (PEGDA) microneedle.

[0038] Beneficial effects of the invention: (1) The present invention obtains a microneedle negative mold with a metal organic aerogel scaffold with a high porosity ratio by freeze drying. In the subsequent microneedle preparation process, the microneedle negative mold can promote the polymer microneedle raw material to enter and fill the pores of the microneedle negative mold through the capillary action mediated by the metal organic aerogel scaffold, thereby eliminating the need for complex centrifugation or vacuum operations, making it possible to commercialize the process of preparing polymer microneedles by micromolding technology. In contrast, similar microneedle negative molds prepared using other hydrogels lack this effect and cannot obtain polymer microneedles with a complete structure without centrifugation and vacuum. (2) The present invention is the first to prepare a microneedle negative mold with a metal organic aerogel scaffold, and it is found that it can improve the subsequent preparation efficiency of polymer microneedles. Therefore, the microneedle negative mold can be used as an intermediate product for microneedle development and directly provided to relevant companies and research institutes, avoiding their complex centrifugation or vacuum operations in the subsequent microneedle preparation process, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings.

[0040] Figure 1 A flow chart showing the preparation process of negative microneedle molds loaded with metal organic aerogel scaffolds.

[0041] Figure 2 A physical picture of the metal-organic aerogel scaffold is shown.

[0042] Figure 3 A photo showing the negative microneedle mold loaded with metal organic aerogel scaffolds.

[0043] Figure 4 A flow chart of the preparation process of polyethylene glycol diacrylate (PEGDA) microneedles prepared by microneedle negative molds loaded with metal organic aerogel scaffolds is shown.

[0044] Figure 5 Microscope photographs of polyethylene glycol diacrylate (PEGDA) microneedles prepared by microneedle negative molds loaded with different aerogel scaffolds are shown (a. metal organic aerogel scaffold; b. hyaluronic acid / polyglutamic acid aerogel scaffold; c. gelatin aerogel scaffold). DETAILED DESCRIPTION

[0045] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0046] Example 1

[0047] A microneedle negative mold loaded with a metal organic aerogel scaffold, the preparation process flow chart is as follows Figure 1 Specifically, the preparation method thereof comprises the steps described below.

[0048] S1. A PDMS microneedle negative mold with micrometer-sized holes is prepared by using a stainless steel microneedle. The holes are a hole array, and the radius of the hole is 250 μm and the length is 400 μm.

[0049] S2. Preparation of metal cobalt organic hydrogel. Use cobalt chloride to prepare an ethanol phase solution A containing divalent cobalt ions, and the molar concentration of the divalent cobalt ions is 57.8mmol / L. Prepare an ethanol phase solution B containing imidazole dicarboxylic acid, triethanolamine, and Tris-HCl buffer, the molar concentration of the imidazole dicarboxylic acid is 154.3mmol / L, the volume fraction of the triethanolamine in solution B is 5.0%, the volume fraction of the Tris-HCl buffer in solution B is 20.0%, and the pH of the Tris-HCl buffer is 8.8. Mix equal volumes of solution A and solution B, stir at room temperature for 1.5 hours, then centrifuge the above reaction solution, wash the centrifugal precipitate with ethanol, and repeat the centrifugal washing 5 times. Disperse the centrifugal precipitate in 1.2mL of deionized water, and let it stand at room temperature for 24 hours to form a metal cobalt organic hydrogel.

[0050] S3. Cast a sufficient amount of metal organic hydrogel onto the surface of the blank PDMS microneedle negative mold, and perform vacuum treatment three times to fully fill the holes of the microneedle negative mold. Each vacuum treatment lasts for 3 minutes, and finally suck away the excess metal organic hydrogel around the hole.

[0051] S4. The microneedle negative mold filled with metal organic hydrogel was stored at -80℃ for 24 hours, and then freeze-dried in a freeze dryer for 18 hours to fully volatilize the water in the metal organic hydrogel and transform the metal organic hydrogel in the microneedle negative mold pores into a metal organic aerogel scaffold. Figure 2 and Figure 3 shown.

[0052] Example 2

[0053] A polyethylene glycol diacrylate (PEGDA) microneedle prepared by a microneedle negative mold loaded with a metal organic aerogel scaffold, the preparation process flow chart is as follows Figure 4 Specifically, the preparation method thereof comprises the steps described below.

[0054] S1. Prepare a negative microneedle mold loaded with a metal organic aerogel scaffold as described in Example 1.

[0055] S2. Prepare a microneedle raw material solution containing PEGDA and a photoinitiator, wherein the volume fraction of the PEGDA is 50%, the photoinitiator is 2-hydroxy-2-methylpropiophenone, and the volume fraction of the photoinitiator in the microneedle raw material solution is 1%.

[0056] S3. Cast the microneedle raw material solution onto the surface of the microneedle female mold loaded with the metal organic aerogel scaffold, and let it stand at room temperature for 15 minutes to allow the microneedle raw material solution to enter the pores of the microneedle female mold through the capillary action mediated by the metal organic aerogel scaffold.

[0057] S4. The microneedle raw material solution in the microneedle negative mold was solidified by ultraviolet light irradiation for 5 minutes, and then the PEGDA microneedle patch was obtained by manual demoulding. Figure 5 (a) shown.

[0058] Comparative Example 1

[0059] A PEGDA microneedle is prepared by a microneedle negative mold loaded with a hyaluronic acid / polyglutamic acid aerogel scaffold, and the preparation method thereof comprises the steps described below.

[0060] S1. Prepare an aqueous solution containing hyaluronic acid and polyglutamic acid, wherein the mass fraction of the hyaluronic acid is 10% and the mass fraction of the polyglutamic acid is 5%. After sufficient stirring, the hyaluronic acid / polyglutamic acid solution is placed in a 4°C refrigerator overnight to form a hyaluronic acid / polyglutamic acid hydrogel. A sufficient amount of hyaluronic acid / polyglutamic acid hydrogel is cast onto the surface of a blank PDMS microneedle negative mold, and is centrifuged to fully fill the holes of the microneedle negative mold. The centrifugation time is 20 minutes, and the speed is 4000 rpm. Finally, the excess hyaluronic acid / polyglutamic acid hydrogel around the hole is cleaned.

[0061] S2. The microneedle negative mold filled with hyaluronic acid / polyglutamic acid hydrogel is stored at -80°C for 48 hours, and then freeze-dried using a freeze dryer for 24 hours to fully evaporate the water in the hyaluronic acid / polyglutamic acid hydrogel, so that the hyaluronic acid / polyglutamic acid hydrogel in the pores of the microneedle negative mold is converted into a hyaluronic acid / polyglutamic acid aerogel scaffold.

[0062] S3. Prepare a microneedle raw material solution containing PEGDA and a photoinitiator, wherein the volume fraction of the PEGDA is 50%, the photoinitiator is 2-hydroxy-2-methylpropiophenone, and the volume fraction of the photoinitiator in the microneedle raw material solution is 1%. Cast the microneedle raw material solution onto the surface of the microneedle negative mold loaded with the hyaluronic acid / polyglutamic acid aerogel scaffold, and let it stand at room temperature for 1 hour.

[0063] S4. The microneedle raw material solution in the microneedle negative mold was solidified by ultraviolet light irradiation for 5 minutes, and then the PEGDA microneedle patch was obtained by manual demoulding. Figure 5 As shown in (b), it can be seen that the integrity of the needle body is lower than that of the PEGDA microneedles prepared by the microneedle negative mold loaded with the metal organic aerogel scaffold.

[0064] Comparative Example 2

[0065] A PEGDA microneedle is prepared by a microneedle negative mold loaded with a gelatin aerogel scaffold, and the preparation method thereof comprises the steps described below.

[0066] S1. Prepare an aqueous solution containing gelatin, wherein the mass fraction of the gelatin is 15%. Heat the gelatin solution in a 60°C oil bath to keep it in a liquid state. Cast a sufficient amount of gelatin solution onto the surface of a blank PDMS microneedle negative mold, and perform a vacuum treatment at 60°C to fully fill the holes of the microneedle negative mold. The vacuum treatment time is 3 minutes. Finally, the excess gelatin solution around the hole is sucked away. Place the microneedle negative mold containing the gelatin solution in a 4°C refrigerator overnight to convert the gelatin solution in the holes of the microneedle negative mold into a gelatin hydrogel.

[0067] S2. The microneedle negative mold filled with gelatin hydrogel was stored at -80°C for 48 hours, and then freeze-dried using a freeze dryer for 24 hours to fully evaporate the water in the gelatin hydrogel and transform the gelatin hydrogel in the pores of the microneedle negative mold into a gelatin aerogel scaffold.

[0068] S3. Prepare a microneedle raw material solution containing PEGDA and a photoinitiator, wherein the volume fraction of the PEGDA is 50%, the photoinitiator is 2-hydroxy-2-methylpropiophenone, and the volume fraction of the photoinitiator in the microneedle raw material solution is 1%. Cast the microneedle raw material solution onto the surface of the microneedle female mold loaded with the gelatin aerogel scaffold and let it stand at room temperature for 1 hour.

[0069] S4. The microneedle raw material solution in the microneedle negative mold was solidified by ultraviolet light irradiation for 5 minutes, and then the PEGDA microneedle patch was obtained by manual demoulding. Figure 5 As shown in (c), it can be seen that compared with the PEGDA microneedles prepared by the microneedle negative mold loaded with the metal organic aerogel scaffold, no microneedle body was formed.

[0070] It should be noted that the preferred embodiments of the present invention are given in the specification and drawings of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not used as additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the present invention; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the protection scope of the claims attached to the present invention.

Claims

1. A microneedle female mold loaded with a metal organic aerogel scaffold, characterized in that: The metal organic aerogel scaffold is loaded in the micrometer-sized holes of the microneedle female mold; The metal organic aerogel scaffold is obtained by freeze drying a metal organic hydrogel formed by coordination interaction between metal and imidazole dicarboxylic acid in the pores.

2. The microneedle negative mold according to claim 1, characterized in that The metal is cobalt.

3. The microneedle negative mold according to claim 1, characterized in that The microneedle negative mold is a polydimethylsiloxane microneedle negative mold.

4. The microneedle negative mold according to claim 1, characterized in that The micron-scale holes of the microneedle female mold are hole arrays, and the radius of the holes is 100-400 μm and the length is 400-1000 μm.

5. A method for preparing a negative mold of a microneedle loaded with a metal organic aerogel scaffold according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) reacting a metal salt with imidazole dicarboxylic acid in an organic solvent under alkaline conditions, collecting the precipitate produced by the reaction by centrifugation, dispersing it in deionized water after washing, and allowing it to stand for 24-72 hours to form a metal organic hydrogel; (2) Filling the obtained metal organic hydrogel into the micron-sized pores of the microneedle negative mold, removing the excess metal organic hydrogel outside the pores, and then fully volatilizing the water in the metal organic hydrogel by freeze drying, so that the metal organic hydrogel in the pores of the microneedle negative mold is transformed into a metal organic aerogel scaffold.

6. The preparation method according to claim 5, characterized in that: The metal salt is a cobalt salt, including cobalt chloride, cobalt formate, cobalt sulfate, cobalt acetate, cobalt citrate, cobalt nitrate or cobalt carbonate; The organic solvent is ethanol or methanol.

7. The preparation method according to claim 5, characterized in that: Step (1) comprises dissolving the metal salt and the imidazole dicarboxylic acid in an organic solvent respectively, and then mixing them to react; The molar concentration of the metal ions in the organic solvent is 10-200 mmol / L; The molar concentration of imidazole dicarboxylic acid in the organic solvent is 100-300 mmol / L; The reaction comprises stirring the reaction at room temperature for 1.5-2 hours; The alkaline conditions are maintained by adding triethanolamine and Tris-HCl buffer; The pH value of the Tris-HCl buffer is 8.0-9.0; The volume fraction of triethanolamine in the imidazole dicarboxylic acid solution is 5%-20%; The volume fraction of the Tris-HCl buffer in the imidazole dicarboxylic acid solution is 10%-40%.

8. The preparation method according to claim 5, characterized in that: In step (2), the metal organic hydrogel is filled into the micrometer-sized pores of the microneedle negative membrane by vacuum degassing; The freeze-drying method includes storing the microneedle negative mold filled with the metal organic hydrogel at -80°C for 12-48 hours, and then using a freeze dryer for freeze drying for 18-48 hours.

9. Use of the metal organic aerogel scaffold-loaded microneedle negative mold according to any one of claims 1 to 4 or the metal organic aerogel scaffold-loaded microneedle negative mold prepared by the preparation method according to any one of claims 5 to 8 for preparing polymer microneedles without centrifugation or vacuum treatment.

10. A polymer microneedle prepared by using the negative mold of the microneedle loaded with a metal organic aerogel scaffold according to any one of claims 1 to 4 or the negative mold of the microneedle loaded with a metal organic aerogel scaffold prepared by the preparation method according to any one of claims 5 to 8.

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