Method for manufacturing composite microneedle patch, and patch for injecting skin care substance and patch for injecting drug manufactured by using same

Abstract

The present invention relates to a method for manufacturing a composite microneedle patch having multiple materials by using inkjet 3D printing and micro-molding technology wherein, more specifically, the method comprises: a first step of pouring a flexible polymer solution into a master mold to manufacture a negative replica mold of a microneedle patch; a second step of printing a first hydrogel on a predetermined area of the mold by using an inkjet 3D printer; a third step of printing a second hydrogel on an area where the first hydrogel is not printed in the mold by using the inkjet 3D printer; a fourth step of forming a base plate by applying a polymer solution on the area where the first hydrogel and the second hydrogel are printed; a fifth step of drying the base plate to which the first and second hydrogels and the polymer solution are applied in the mold in an environment of 35-38°C; and a sixth step of separating, from the mold, the base plate on which the first and second hydrogels and the polymer solution have been applied.

Description

Method for manufacturing a composite microneedle patch and a patch for injecting skin cosmetic substances and a patch for injecting drugs manufactured using the same

[0001] The present invention relates to a method for manufacturing a composite microneedle patch and a patch for injecting skin cosmetic substances and a patch for injecting drugs manufactured using the same. Specifically, it relates to a technology for manufacturing a composite microneedle patch having multiple materials using inkjet 3D printing and micro-molding technology, and a microneedle patch manufactured thereby.

[0002] Microneedles are devices used to inject growth factors or drugs into skin tissue. Since these microneedles enable localized and continuous drug delivery and minimize pain during insertion, their use in various fields has been rapidly increasing recently. Representative examples include patches that promote wound healing by inducing angiogenesis in scar tissue, patches to prevent motion sickness, nicotine patches to aid in smoking cessation, pain relief patches, and relatively recently developed patches for treating dementia and Parkinson's disease.

[0003] Microneedles are needles with a height of about 200 to 1,000 µm in the form of patches, which are long enough to penetrate the epidermal layer of the skin and reach the dermal layer. Compared to existing drug delivery methods such as patches and creams, they have high drug efficiency and, compared to intravenous injection, have the characteristics of lower pain and lower expertise.

[0004] Methods for fabricating such microneedle patches include the micro-molding method, which involves creating a mold with an inverse phase using a master mold and fabricating it through centrifugation or vacuum by filling it with material; the microneedle patch fabrication method, which involves stacking micrometer-sized layers using a high-precision 3D printer; and the drawing lithography method, which involves pressing and peeling off high-viscosity materials using a special punch. However, because these microneedle fabrication methods have limitations such as complex manufacturing processes, a narrow range of material choices, and the use of a single material, there is a need for more economical microneedle patch fabrication technology.

[0005] The present invention aims to provide a manufacturing technology for microneedles with high resolution by improving the conventional microneedle manufacturing method to provide a more convenient manufacturing technology. In addition, the present invention aims to provide a technology that can print two or more materials at once using a 3D printer with multiple nozzles, and thus has high versatility by using two or more materials in a single microneedle patch.

[0006] The present invention relates to a method for fabricating a composite microneedle patch having multiple materials using inkjet 3D printing and micro-molding technology, and the specific process comprises: a first step of fabricating a mold having an inverse shape of a microneedle patch using one or more flexible polymer materials selected from the group including Polydimethylsiloxane (PDMS), Ecoflex, polyurethane (PU), Polytetrafluoroethylene (PTFE), and Polypropylene (PP) in a master mold; a second step of printing a first hydrogel in a predetermined area of ​​the mold using an inkjet 3D printer; and a third step of printing a second hydrogel in an area of ​​the mold where the first hydrogel was not printed using an inkjet 3D printer. The method is characterized by comprising: a fourth step of forming a base plate by applying one or more polymer materials selected from the group including Polyvinyl alcohol (PVA), Polylactic-co-Glycolic Acid (PEVA), Polyethylene glycol (PEG), and Polyethylene Terephthalate (PET) onto the printed first and second hydrogels; a fifth step of drying the base plate coated with the first and second hydrogels and the polymer solution on the mold in an environment of 35-38°C; and a sixth step of separating the base plate coated with the first and second hydrogels and the polymer solution from the mold.

[0007] The first hydrogel is a GelMA solution, and the second hydrogel is a gelatin solution. The first hydrogel contains 0.1% of a photocrosslinking agent and is crosslinked under UV (495 nm), and the second hydrogel is gelated for 5-15 minutes in an environment of 2-4°C.

[0008] The first hydrogel comprises one or more biomaterials selected from the group consisting of gelatin methacrylate solution (GelMA solution), silk fibroin methacrylate solution (SilMA solution), hyaluronic acid methacrylate solution (HAMA solution), and dECM solution (Decellularized extracellular matrix hydrogels / solutions).

[0009] The second hydrogel comprises one or more biomaterials selected from the group consisting of gelatin solution, fibrin solution, collagen solution, chitosan solution, and dECM solution (Decellularized extracellular matrix hydrogels / solutions).

[0010] The size of the above needle is configured such that the bottom surface is 0.4x0.4mm and the height is 0.6-1.0mm, penetrating the stratum corneum and epidermis of human skin and reaching only the dermis layer.

[0011] One or more materials selected from the group including drugs, growth factors, antibodies, proteins, vaccines, enzymes, cells, and stem cells are loaded into the internal three-dimensional matrix structure of GelMA and Gelatin constituting the first and second hydrogels.

[0012] The above polymer is formed at a concentration of 10-40 w / v% to ensure the flexible properties (10 w / v%) and mechanical stability (~40 w / v%) of the base plate.

[0013] The above first step consists of: step 1-1, producing a master mold using laser 3D printing; step 1-2, pouring the flexible polymer solution into the master mold and curing it at 60-80°C for 4-12 hours; and step 1-3, removing the master mold to produce a flexible polymer mold having an inverse of a microneedle patch.

[0014] In addition, the present invention relates to a patch for injecting skin cosmetic substances or a patch for injecting drugs produced by a method for producing a composite microneedle patch.

[0015] The present invention enables the production of microneedles with high resolution through the above configuration, and has the effect of easily producing microneedle patches having two or more materials by printing two or more materials at once using a 3D printer with multiple nozzles.

[0016] Figure 1 shows the material selection and overall schematic diagram of the microneedle patch in the method for fabricating a composite microneedle patch according to the present invention.

[0017] FIG. 2 is a schematic diagram of the integration of an inkjet 3D printer and injection molding as a microneedle patch fabrication process according to the present invention.

[0018] FIG. 3 is an image of a hydrogel-based microneedle patch according to the present invention, (A) is an overall image of the microneedle patch viewed at a certain angle, and (B) is an overall image of the fabricated microneedle patch held by the experimenter. (C) is an overall image of a gelatin-based microneedle patch viewed from above, and (D) is a side magnified image of the gelatin-based microneedle. (E) is an overall image of a gelMA-based microneedle patch viewed from above, and (F) is a side magnified image of the gelMA-based microneedle patch.

[0019] Figure 4 is an SEM image of GelMA and Gelatin-based microneedles in a microneedle patch according to the present invention.

[0020] Figure 5 (A) shows an experiment on inkjet 3D printer output conditions of a gelatin solution, and (B) shows an experiment on inkjet 3D printer output conditions of a gelMA solution.

[0021] Figure 6 is an image of a microneedle patch fabricated with a single needle in various patterns based on the printability results of Gelatin and GelMA used in the present invention.

[0022] Figure 7 shows an analysis of the solubility and swelling characteristics of the GelMA and Gelatin-based microneedles of the present invention, (A) is an image of swelling of the GelMA-based microneedles over time in an agarose gel environment, (B) is a graph of weight change over time and concentration of the GelMA-based microneedles measured in an agarose gel environment, (C) is an image of dissolution over time of the Gelatin-based microneedles in an agarose gel environment, and (D) is a graph of height change over time and concentration of the Gelatin-based microneedles measured in an agarose gel environment.

[0023] Figure 8 (A) shows the mechanical strength measurement according to the concentration of GelMA-based microneedles, and (B) shows the mechanical strength measurement according to the concentration of Gelatin-based microneedles.

[0024] (A) of Fig. 9 is an image of a Gelatin / FITC-dextran microneedle upon UV irradiation, (B) is an image of a GelMA / FITC-dextran and GelMA upon UV irradiation (Green: GelMA / FITC-dextran, Blue: GelMA), (C) is an image of a GelMA / FITC-dextran taken using a fluorescence microscope, (D) is an image of a microneedle patch fabricated using GelMA / FITC-dextran and GelMA with half of each area and then irradiated with UV, and (E) is an image of a GelMA / FITC-dextran and GelMA after alternating printing and then irradiated with UV.

[0025] Figure 10 (A) shows the results of measuring the FITC-dextran fluorescence emission according to the Gelatin concentration in a DPBS environment, and (B) shows the results of measuring the BSA-FITC fluorescence emission according to the GelMA concentration in a DPBS environment.

[0026] Figure 11 shows the Live / Dead fluorescence images and CCK-8 bar graphs of three experimental groups: DMEM-based Control, PVA / GelMA-based microneedles (MNs), and PVA / Gelatin-based MNs. (A) is the Live / Dead fluorescence image on Day 1 (Green: Live cells), (B) is the Live / Dead fluorescence image on Day 4 (Green: Live cells), and (C) is the CCK-8 bar graph for Day 1 and Day 4 of the three experimental groups.

[0027] FIG. 12 shows the shape and dimensions of a microneedle patch master mold according to the present invention, and

[0028] FIG. 13 shows the bottom surface size of a single needle provided in the master mold of FIG. 12.

[0029] The objects, specific advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings. Additionally, the terms used are defined with respect to their functions in the present invention, which may vary according to the user's intent or practice. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0030] In addition, when describing the components of the present invention, different reference numerals may be assigned to components with the same name depending on the drawing, and the same reference numeral may be assigned even if they are different drawings. However, even in such cases, this does not mean that the components have different functions depending on the embodiment, or that they have the same function in different embodiments, and the function of each component should be determined based on the description of each component in the corresponding embodiment.

[0031] Furthermore, technical terms used in this specification shall be interpreted in the sense generally understood by those skilled in the art to which the present invention pertains, unless specifically defined otherwise in this specification, and shall not be interpreted in an overly broad or overly narrow sense. Additionally, singular expressions used in this specification include plural expressions unless the context otherwise indicates.

[0032] The present invention relates to a hydrogel-based microneedle patch fabrication technology that integrates high-precision inkjet 3D printer technology and a micro-molding technique, and a technology utilizing the same. By using a 3D printer with multiple nozzles, two or more materials can be printed at once, and thus, high versatility is secured by using two or more materials in a single microneedle patch.

[0033] The master mold used in the present invention was fabricated using high-precision laser 3D printing. A PDMS solution was poured into the fabricated master mold and cured in an oven at 60-80°C for 4-12 hours, after which the master mold was removed to finally produce a PDMS mold with an inverted phase. Additionally, gelatin and GelMA, which have high biocompatibility and excellent polymer loading capabilities such as drugs and enzymes in the internal 3D matrix, were used for the microneedles. Furthermore, to ensure the flexibility and mechanical stability of the microneedle patch, a PVA (Polyvinyl Alcohol, 10-40 w / v%) solution was used for the base plate.

[0034] Figure 1 is a schematic diagram of the microneedle patch fabrication process, integrating an inkjet 3D printer and micro-molding, and Figure 2 is a schematic diagram of the material selection and fabrication of the fabricated microneedle patch.

[0035] The materials used in the present invention are gelatin and GelMA (Gelatin Methacryloyl) powder mixed with 1XPBS or DW and used in the form of a solution at 1w / v%, 3w / v%, and 5w / v%.

[0036] For GelMA, a photocrosslinking agent (0.1%) was added to enable crosslinking under UV light (495 nm). The prepared GelMA and Gelatin solutions were printed using an inkjet 3D printer, and the printed GelMA solutions were photocrosslinked by UV irradiation for 2–3 minutes. The Gelatin solutions were subjected to gelation in a refrigerator (2–4°C) for 5–15 minutes. 350–450 µL of PVA solution (10–40 w / v%) was poured over the fabricated GelMA and Gelatin microneedles, and they were dried in an oven (35–38°C) for one day. After drying, they were detached from the PDMS mold to produce the final PVA@GelMA and Gelatin microneedle patches, which were then stored at room temperature. (If loaded with drugs or enzymes, they were stored under appropriate temperature conditions.)

[0037] For the 3D model running on the inkjet 3D printer, a 3D shape with the same position and area as the needle portion of the master mold was designed using an inverter, converted into an STL file, and then the inkjet 3D printer was operated. The master mold has a cube with dimensions of 15mm width, 15mm length, and 2mm height, and each microneedle was designed as a 6x6 grid with a spacing of 2.2mm. The microneedles consist of tetrahedrons with dimensions of 400um width, 400um length, and 600-1,000um height.

[0038] Prior to fabricating the microneedle patch, appropriate printing conditions for the inkjet 3D printer were verified. A total of three printing variables were set. The printing temperature was fixed at 38°C to maintain a stable liquid state for GelMA and Gelatin. Regarding the valve opening time (usec), since normal printing does not occur above a certain value, it was fixed to specific printing conditions for each hydrogel (Gelatin: 300 usec, GelMA: 330 usec). Finally, the weight of the printed object was measured according to the printing variables to confirm the optimal printing conditions that would allow it to fit accurately into the fabricated PDMS mold. The experimental results confirmed that the weight of the droplet increased as the pressure increased, and that the weight of the droplet increased as the concentration of the hydrogel decreased.

[0039] To investigate the characteristics of the microneedle patch produced in the present invention, the high resolution of the needles was first confirmed using a scanning electron microscope (SEM), and the appropriate mechanical strength (0.1 N / MN) required for skin penetration was confirmed using a compression strength tester. In addition, the solubility and swelling properties were confirmed for 0-90 seconds in an agarose gel (5 w / v%) environment depending on the Gelatin and GelMA used. Subsequently, a total of six microneedle outputs with patterned 3D shapes were modeled and printed, including complete area, half area, alternating, K, N, and U, and these were verified using a microscope.

[0040] To demonstrate the utility of the fabricated hydrogel-based microneedle patch as a drug delivery system for wound healing, the drug loading and release profiles were verified according to the hydrogel concentration and type. In this case, FITC-Dextran (Ex / Em=492 / 518nm) and BSA-FITC (Ex / Em=499 / 527nm) were loaded into Gelatin and GelMA, respectively; Gelatin / FITC-dextran mimicked the release behavior of the drug, while GelMA / BSA-FITC mimicked the release behavior of vascular endothelial growth factor (VEGF). Subsequently, the fluorescence emission of the fabricated microneedle patch was measured using a microplate reader at 10-minute intervals for 0 to 60 minutes.

[0041] Figure 3 is an image of a hydrogel-based microneedle patch, (A) is an overall image of the microneedle patch viewed from above, (B) is a magnified side view of the microneedle, and (C) is an overall image of the microneedle patch viewed from the side.

[0042] Figure 4 is an SEM image of a GelMA and Gelatin-based microneedle in a microneedle patch according to the present invention, and Figure 5 (A) shows an experiment on inkjet 3D printer output conditions of a Gelatin solution, and (B) shows an experiment on inkjet 3D printer output conditions of a GelMA solution. Figure 6 is an image of a microneedle patch fabricated with a single needle in various patterns based on the printability results of Gelatin and GelMA, which was fabricated using K, N, U printing, Alternating printing, and Half area printing, respectively, according to the 3D CAD design shape.

[0043] Figure 7 shows the characteristics of the fabricated GelMA and Gelatin-based microneedles analyzed in an agarose gel environment. During this process, the Gelatin-based microneedles were measured to decrease in height as they dissolved according to the agarose gel insertion time, while the GelMA-based microneedles were measured to increase in weight as they swelled according to the agarose gel insertion time. As a result, both GelMA and Gelatin exhibited the fastest swelling and dissolution rates at the lowest concentration of 1 w / v%. However, because it was difficult to maintain the shape of the GelMA and Gelatin microneedles and fabrication was unstable, 3% and 5% GelMA and Gelatin were ultimately selected.

[0044] Figure 8 shows the compressive strength measured using a compression tester to verify the stable skin penetration of the fabricated microneedle patch. When the force acting on the microneedle patch at a displacement of 0.8 mm, where the maximum force can be applied to the designed microneedle, was determined, it was confirmed that the higher the concentration, the higher the compressive strength. At this time, the minimum force required to penetrate the stratum corneum and epidermal layer of the skin is 0.1 N / MN, and the experimental results confirmed that all fabricated hydrogels of various concentrations possess sufficient skin penetration ability.

[0045] To demonstrate its potential as a future drug delivery system, the present invention mimicked the loading of drugs by loading FITC-dextran fluorescent material into each Gelatin and GelMA solution. The microneedle patch loaded with fluorescent material was irradiated with UV light to confirm that the fluorescent material was successfully loaded inside the needle.

[0046] (A) of Fig. 9 is an image of a Gelatin / FITC-dextran microneedle upon UV irradiation, (B) is an image of a GelMA / FITC-dextran and GelMA upon UV irradiation (Green: GelMA / FITC-dextran, Blue: GelMA), (C) is an image of a GelMA / FITC-dextran taken using a fluorescence microscope, (D) is an image of a microneedle patch fabricated using GelMA / FITC-dextran and GelMA with half of each area and then irradiated with UV, and (E) is an image of a GelMA / FITC-dextran and GelMA after alternating printing and then irradiated with UV.

[0047] Figure 10 shows the results of measuring the emitted fluorescence using a microplate reader after immersing GelMA / FITC-dextran and Gelatin / BSA-FITC microneedle patches in DPBS (5 ml) to mimic the drug release behavior environment of the fabricated microneedle patches. In the case of the Gelatin / FITC-dextran microneedle, explosive fluorescence emission was observed at 10-20 minutes for 3% Gelatin and at approximately 30-40 minutes for 5% Gelatin. The GelMA / BSA-FITC microneedle showed relatively steady fluorescence emission up to approximately 50 minutes, and it was confirmed that the fluorescence emission stabilized at approximately 50-60 minutes for both 3% GelMA and 5% GelMA. Through this, it was confirmed that polymers such as the fluorescent material of the fabricated microneedle can be loaded, and that drug release can be controlled depending on the concentration and type of hydrogel.

[0048] Referring to Fig. 11, the microneedle patch fabricated in the present invention evaluated the normal growth and biocompatibility of vascular cells, which is one of the wound healing stages, using EA.hy926 cells. EA.hy926 cells were cultured at a rate of 1 x 10^5 cells per well in a cell culture dish (6 wells). Subsequently, a Live / Dead test and a CCK-8 test were performed on Day 1 and Day 4 of the culture period. High biocompatibility of PVA / GelMA-based MNs and PVA / Gelatin-based MNs was confirmed through Live / Dead fluorescence imaging, and normal proliferative activity of EA.hy926 cells was confirmed through the CCK-8 results.

[0049] FIG. 12 shows the shape and dimensions of one embodiment of a microneedle patch master mold according to the present invention, and FIG. 13 shows the bottom surface size of a single needle provided in the master mold. The size of the entire patch of the master mold is 15x15mm, and the needles consist of a total of 36 needles in a 6x6 configuration, with a spacing of 2.2mm between the needles. The size of a single needle consists of a bottom surface of 0.4x0.4mm and a height of 0.6-0.8mm. The size of the needle designed in this way has a height capable of penetrating the stratum corneum and epidermal layer (0.05~0.1mm) of the skin and reaching only up to the dermal layer (0.5~1.1)mm.

[0050] The present invention allows drugs, growth factors, or enzymes to be loaded into an internal three-dimensional matrix structure by using gelatin and GelMA among various hydrogels, and ensures the stability of drugs and enzymes because it is manufactured at a relatively low temperature (38℃). In addition, the 3D model designed for inkjet 3D printing can be easily modified, making it applicable to the production of personalized microneedle patches.

[0051] Recently, microneedle patches have been commercialized and are continuously sold in the cosmetics industry, with new products targeting various diseases being steadily released. However, since currently commercialized microneedle patches are primarily manufactured using micro-molding or drawing lithography methods, they are more expensive than conventional plain patches, and microneedles composed of a single material account for a large proportion. To address these issues, this study presents a technology capable of rapidly fabricating microneedle patches loaded with two or more materials at high resolution, providing a novel approach to the mass production process of microneedle patches.

[0052] Therefore, the present invention includes a patch for injecting skin cosmetic substances and a patch for injecting drugs, produced by a method for producing a composite microneedle patch.

[0053] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. A first step of fabricating a mold having an inverse of a microneedle patch using one or more flexible polymer materials selected from the group including Polydimethylsiloxane (PDMS), Ecoflex, polyurethane (PU), Polytetrafluoroethylene (PTFE), and Polypropylene (PP) in a master mold; A second step of printing a first hydrogel onto a predetermined area of ​​the mold using an inkjet 3D printer; A third step of printing a second hydrogel using an inkjet 3D printer in an area of ​​the mold where the first hydrogel is not printed; and A fourth step of forming a base plate by applying one or more polymer materials selected from the group comprising Polyvinyl alcohol (PVA), Polylactic-co-Glycolic Acid (PEVA), Polyethylene glycol (PEG), and Polyethylene Terephthalate (PET) onto the printed first hydrogel and second hydrogel; A method for producing a composite microneedle patch characterized in that the first and second hydrogels form needles.

2. In Paragraph 1, Step 5, after Step 4, drying the base plate coated with the first and second hydrogels and the polymer solution on the mold in an environment of 35-38°C; and A method for fabricating a composite microneedle patch, characterized by including: a sixth step of separating a base plate coated with the first and second hydrogels and a polymer solution from the mold.

3. In Paragraph 2, The first hydrogel comprises one or more biomaterials selected from the group consisting of gelatin methacrylate solution (GelMA solution), silk fibroin methacrylate solution (SilMA solution), hyaluronic acid methacrylate solution (HAMA solution), and dECM solution (Decellularized extracellular matrix hydrogels / solutions). A method for fabricating a composite microneedle patch, characterized in that the second hydrogel comprises one or more biomaterials selected from the group consisting of gelatin solution, fibrin solution, collagen solution, chitosan solution, and dECM solution (Decellularized extracellular matrix hydrogels / solutions).

4. In Paragraph 2, The first hydrogel above contains 0.1% of a photocrosslinking agent and is crosslinked under UV (495 nm), and A method for producing a composite microneedle patch characterized in that the second hydrogel above gelates under refrigeration (2-4℃).

5. In Paragraph 1, The size of the above needle is configured such that the bottom surface is 0.4x0.4mm and the height is 0.6-1.0mm, A method for producing a composite microneedle patch characterized by penetrating the stratum corneum and epidermal layer of human skin and reaching only the dermal layer.

6. In Paragraph 3, A method for fabricating a composite microneedle patch characterized by loading one or more materials selected from the group comprising drugs, growth factors, antibodies, proteins, vaccines, enzymes, cells, and stem cells into the internal three-dimensional matrix structure of GelMA and Gelatin constituting the first and second hydrogels.

7. In Paragraph 1, A method for fabricating a composite microneedle patch, characterized in that the above polymer solution is formed at a concentration of 10-40 w / v% to ensure flexibility and mechanical stability of the base plate.

8. In paragraph 1, the first step is, Step 1-1 of fabricating a master mold using high-precision laser 3D printing; and Step 1-2, pouring a flexible polymer solution into the above master mold and curing it at 60-80°C for 4-12 hours; and A method for producing a composite microneedle patch characterized by comprising steps 1-3 of removing the above master mold to produce a mold having an inverse phase of the microneedle patch.

9. A patch for injecting skin cosmetic substances produced by the method for producing a composite microneedle patch of claim 1.

10. A drug injection patch produced by the method for producing a composite microneedle patch of claim 1.

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