Microneedle structure containing shape memory polymer and method for producing same

Abstract

A microneedle structure according to one aspect of the present invention is a microneedle structure including a microneedle to be inserted into skin, and may include a microneedle including a shape memory polymer and formed to be deformable from a first shape to a second shape in response to a predetermined external stimulus due to the properties of the shape memory polymer, and a support member having the microneedle formed on one surface.

Description

[Technical field]

[0001] The present invention relates to a microneedle structure including a shape memory polymer and a method for manufacturing the same, and more particularly to a microneedle structure that can be easily removed from the skin by utilizing the properties of a shape memory polymer and a method for manufacturing the same. [Background technology]

[0002] There are two methods for delivering drugs into the human body: oral administration and transdermal drug delivery. Oral administration has the advantage of being easy to take, but has the disadvantages of drug degradation in the gastrointestinal tract, loss due to hepatic metabolism, and difficulty in removing the drug after administration.

[0003] The transdermal drug delivery system delivers drugs directly into the body by injection and is therefore more effective than oral administration systems, but has the disadvantages of causing severe pain, patient refusal and skin damage.

[0004] To overcome the drawbacks of conventional oral administration systems and transdermal drug delivery systems, microneedles and microneedle structures having a length of several hundred micrometers (μm, micrometer) have been developed. Microneedles and microneedle structures have the advantages of being able to deliver drugs directly into the body, not causing pain, and minimizing skin damage.

[0005] Conventional microneedles and microneedle structures have been configured such that the microneedles are coated with a drug, and when injected into the body, only the drug dissolves and the microneedle is removed, or the microneedle dissolves completely after being inserted into the body, or the microneedle has a hollow structure with a hole at the end and a hydrogel dosage form to deliver the drug.

[0006] However, conventional microneedles and microneedle structures have been researched from the perspective of drug delivery, and no active research and development has been conducted from the perspective of removal after drug delivery or during use, resulting in the problem that they are not easy to remove after use.

[0007] Therefore, there has been a demand for the development of a microneedle structure and a manufacturing method thereof that can be stably fixed to the skin while a drug is being administered into the body, and can be easily removed from the skin after drug delivery or in situations where removal is required. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention is intended to solve the problems described above, and an object of the present invention is to provide a microneedle and a microneedle structure that can be stably fixed after the microneedle is inserted into the skin, and a method for manufacturing the same.

[0009] Another object of the present invention is to provide a microneedle and a microneedle structure whose shape can be changed after being inserted into the skin, and a method for manufacturing the same.

[0010] It is yet another object of the present invention to provide a microneedle and a microneedle structure that can be easily removed from the skin, and a method for producing the same.

[0011] The object of the present invention is not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0012] According to one aspect of the present invention, there is provided a microneedle structure including a microneedle to be inserted into the skin, the microneedle including a shape memory polymer and formed so as to be deformable from a first shape to a second shape in response to a predetermined external stimulus due to the properties of the shape memory polymer, and a support member having the microneedle formed on one surface.

[0013] Here, the first shape may include a body portion having a cross-section that becomes smaller toward one side, and a head portion extending from one side of the body portion and having a cross-section larger than the cross-section of the one side of the body portion.

[0014] Here, the head portion may have a cross section that becomes smaller toward the tip.

[0015] Here, the second shape may be a cone shape.

[0016] Here, the second shape may be formed flat on the one surface of the support member.

[0017] Here, the microneedle may be formed so that it is inserted into the skin while having the first shape, changes shape from the first shape to the second shape while inserted into the skin, and is removed from the skin while having the second shape.

[0018] Here, an outer skin layer is formed on the outer surface of the microneedle, and the outer skin layer may contain a pharmaceutical composition.

[0019] Here, an injection port is formed at the end of the microneedle, an injection tube is formed inside the microneedle, one side of which is connected to the injection port, and the microneedle may further include a reservoir connected to the other side of the injection tube and containing a pharmaceutical composition.

[0020] Here, the predetermined stimulus may include at least one of a temperature change and ultraviolet light irradiation.

[0021] Here, the shape memory polymer may include at least one of a biodegradable shape memory polymer or a biocompatible shape memory polymer.

[0022] Here, the biocompatible shape-memory polymer may include at least one of polycaprolactone with crosslinked acrylated end-groups, network structured polycaprolactone, polycaprolactone blend with polyurethane, cellulose grafted polycaprolactone, polycaprolactone-co-polysiloxane, multi-arm structured polycaprolactone, multi-arm structured polylactic acid, poly(lactic acid) copolymer, and poly(lactic acid)-co-poly(ethylene glycol) copolymer.

[0023] Here, the predetermined stimulus may include a temperature change, and the microneedle may gradually deform as the temperature changes around a reference temperature, and may have a first shape at a first temperature below the reference temperature and a second shape at a second temperature above the reference temperature.

[0024] Here, the reference temperature may be in the range of 28°C to 42°C.

[0025] Here, the number of the microneedles may be multiple, and the multiple microneedles may be regularly arranged at regular intervals.

[0026] Here, the plurality of microneedles may include first and second microneedles, and the first shape of the first microneedle and the first shape of the second microneedle may be different from each other.

[0027] According to another aspect of the present invention, there is provided a method for manufacturing a microneedle structure including a microneedle that contains a shape memory polymer and is deformable from a first shape to a second shape in response to a predetermined external stimulus due to the properties of the shape memory polymer, and a support member on one side of which the microneedle is formed, the method including the steps of: molding a microneedle having the second shape using a shape memory polymer; adjusting a temperature so that the microneedle having the second shape is variable; and molding the microneedle such that the microneedle whose temperature has been adjusted has the first shape.

[0028] Here, the step of forming the second shape may include the steps of applying the shape memory polymer onto one surface of a mold for a second shape, in which an intaglio for a second shape corresponding to the second shape is formed, and applying pressure so that a portion of the shape memory polymer flows into the inside of the intaglio for the second shape.

[0029] Here, the step of molding the second shape may include a step of forming a support member by spreading a remainder of the shape memory polymer, except for the portion, onto the one surface of the mold for the second shape centered on the depression for the second shape, as pressure is applied to the shape memory polymer.

[0030] Here, forming the second shape may include mixing the shape-memory polymer with a thermal crosslinking initiator and applying heat to the shape-memory polymer.

[0031] Here, the thermal crosslinking initiator may include at least one of potassium persulfate, ammonium persulfate, benzoyl peroxide, dilauroyl peroxide, dicumyl peroxide, hydrogen peroxide, and azobisisobutyronitrile.

[0032] Here, forming the second shape may include mixing the shape-memory polymer with a photocrosslinking initiator and applying ultraviolet light to the shape-memory polymer.

[0033] Here, the photocrosslinking initiator may include at least one of Darocure, Irgacure, LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate) having a phenyl phosphine structure, TPO (Diphenyl(2,4,6-Trimethylbenzoyl)Phosphine), and TPO-L (Ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate).

[0034] Here, the step of molding the first shape may include a step of placing the microneedle having the second shape in a depression for a first shape formed on one side of a mold for a first shape to correspond to the first shape, and a step of pressing the microneedle against the inside of the depression for the first shape.

[0035] Here, after the forming of the first shape, the method may include cooling the microneedle to a low temperature so as to fix the first shape of the microneedle, and then maintaining the cooled state.

[0036] Here, the method may include attaching the microneedle having the first shape to a support member after the step of forming the first shape.

[0037] Here, the step of molding the first shape may include the steps of placing the microneedle having the second shape in a depression for a first shape formed on one surface of a mold for a first shape to correspond to the first shape, applying an adhesive member to one side of the microneedle, and pressing the microneedle against the inside of the depression for the first shape. Effect of the Invention

[0038] As a result of the above-mentioned configuration, the microneedle and microneedle structure and its manufacturing method according to the embodiment of the present invention provide a microneedle having an arrowhead shape so that it does not fall off after being inserted into the skin, thereby enabling the microneedle to be stably fixed after being inserted into the skin.

[0039] Furthermore, the microneedle and microneedle structure and manufacturing method thereof according to the embodiments of the present invention provide a microneedle including a shape-memory polymer capable of changing its shape, thereby enabling the microneedle to change its shape after being inserted into the skin.

[0040] In addition, the microneedles and microneedle structures and manufacturing methods thereof according to embodiments of the present invention provide microneedles that are capable of being inserted into the skin while in a first shape that has a high adhesive strength with the skin, and then being deformed into a second shape that has a low adhesive strength with the skin, thereby allowing the microneedles to be easily removed from the skin.

[0041] It should be understood that the effects of the present invention are not limited to the effects described above, but include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. [Brief description of the drawings]

[0042] [Figure 1] FIG. 1 is a perspective view of a microneedle structure according to a first embodiment of the present invention, where (a) of FIG. 1 is a diagram showing a state in which the microneedle has a first shape, and (b) of FIG. 1 is a diagram showing a state in which the microneedle has a second shape. [Diagram 2] FIG. 2 is a diagram showing a process in which microneedles are inserted into the skin by the microneedle structure according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a process in which after a microneedle is inserted into the skin by the microneedle structure according to the first embodiment of the present invention, a predetermined stimulus is applied to the microneedle structure, causing the microneedle to deform from a first shape to a second shape. [Figure 4] FIG. 4 is a diagram showing a process in which the microneedles are transformed into a second shape by the microneedle structure according to the first embodiment of the present invention and then removed from the skin. [Diagram 5] FIG. 5 is a photograph of an experiment conducted to confirm the fixation of a microneedle having a first shape according to the first embodiment of the present invention, where (a) of FIG. 5 is a photograph showing a state in which a microneedle is inserted into a hydrogel that mimics skin tissue, and (b) and (c) of FIG. 5 are photographs showing the process of lifting the microneedle outside the hydrogel. [Figure 6] Figure 6 is a perspective view of a microneedle structure according to a second embodiment of the present invention, where (a) of Figure 6 is a diagram showing a state in which the microneedle has a first shape, and (b) of Figure 6 is a diagram showing a state in which the microneedle has a second shape. [Figure 7] Figure 7 is a perspective view of a microneedle structure according to a third embodiment of the present invention, where (a) of Figure 7 is a diagram showing a state in which the microneedle has a first shape, and (b) of Figure 7 is a diagram showing a state in which the microneedle has a second shape. [Figure 8] FIG. 8 is a flow chart of a method for manufacturing a microneedle structure according to an embodiment of the present invention. [Figure 9a]FIG. 9a is a view for explaining the manufacturing method of the microneedle structure according to the first embodiment of the present invention. [Figure 9b] FIG. 9b is a view for explaining the manufacturing method of the microneedle structure according to the first embodiment of the present invention. [Figure 9c] FIG. 9c is a view for explaining the manufacturing method of the microneedle structure according to the first embodiment of the present invention. [Figure 9d] FIG. 9d is a view for explaining the manufacturing method of the microneedle structure according to the first embodiment of the present invention. [Figure 10a] FIG. 10a is a view for explaining a manufacturing method of a microneedle structure according to the second embodiment of the present invention. [Figure 10b] FIG. 10b is a view for explaining the method of manufacturing a microneedle structure according to the second embodiment of the present invention. [Figure 10c] FIG. 10c is a view for explaining the manufacturing method of the microneedle structure according to the second embodiment of the present invention. [Figure 10d] FIG. 10d is a view for explaining the manufacturing method of the microneedle structure according to the second embodiment of the present invention. [Figure 10e] FIG. 10e is a view for explaining a manufacturing method of a microneedle structure according to the second embodiment of the present invention. [Figure 11a] FIG. 11a is a view for explaining a manufacturing method of a microneedle structure according to the third embodiment of the present invention. [Figure 11b] FIG. 11b is a view for explaining the manufacturing method of the microneedle structure according to the third embodiment of the present invention. [Figure 11c] FIG. 11c is a view for explaining the method of manufacturing a microneedle structure according to the third embodiment of the present invention. [Figure 11d] FIG. 11d is a view for explaining the manufacturing method of the microneedle structure according to the third embodiment of the present invention. [Figure 12]Figure 12 is a photograph showing a microneedle structure array manufactured by a microneedle structure manufacturing method according to an embodiment of the present invention, where (a) of Figure 12 is a photograph of a microneedle structure formed into a second shape by one step of the manufacturing method according to this embodiment, (b) of Figure 12 is a photograph of the microneedle structure before an external stimulus is applied, and (c) of Figure 12 is a photograph of the microneedle structure whose shape has been deformed after an external stimulus is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention, parts not related to the description are omitted in the drawings, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0044] The words and terms used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed in a meaning or concept that is consistent with the technical idea of ​​the present invention according to the principle that the inventor can define the terms and concepts in order to best describe his / her invention.

[0045] As used herein, terms such as "comprise" or "have" are intended to describe the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0046] When a component is "in front of," "in back of," "above," or "below" another component, it does not only mean that the component is directly abutted against the other component and is disposed "in front of," "in back of," "above," or "below," but also means that another component is disposed between them, unless there are special circumstances. Furthermore, when a component is "connected" to another component, it does not only mean that the components are directly connected to each other, but also means that the components are indirectly connected to each other, unless there are special circumstances.

[0047] The microneedles and microneedle structures and their manufacturing methods according to the embodiments of the present invention relate to an invention that can provide microneedles that can be stably fixed to the skin, deliver drugs into the body, and be easily removed from the skin by using the properties of a shape-memory polymer to enable the microneedle to be deformed from a shape that has a high adhesive strength to the skin to a shape that has a low adhesive strength to the skin.

[0048] In the following description of the drawings, each direction will be defined based on Fig. 1. More specifically, the direction in which the microneedles protrude from the support member is defined as the lower direction, and the opposite direction is defined as the upper direction.

[0049] FIG. 1 is a perspective view of a microneedle structure according to a first embodiment of the present invention, where (a) of FIG. 1 is a diagram showing a state in which the microneedle has a first shape, and (b) of FIG. 1 is a diagram showing a state in which the microneedle has a second shape.

[0050] 1, a microneedle structure 1 according to a first embodiment of the present invention may include a support member 10 and microneedles 20, 20'. The support member 10 may provide a base on which the microneedles 20, 20' are formed or attached.

[0051] The support member 10 may be made of a plate-shaped member having a predetermined thickness. Here, the support member 10 may be formed so as to have a predetermined elasticity or flexibility so as to be easily bent, so that it can be easily held on the skin. Of course, the support member 10 may be made of a thin film.

[0052] Microneedles 20, 20' may be formed on one surface of the support member 10, that is, the lower surface with reference to Fig. 1. Here, the number of microneedles 20, 20' may be multiple, and the multiple microneedles 20, 20' may be regularly arranged at predetermined intervals apart from each other.

[0053] In this embodiment, the microneedles 20, 20' are arranged in five rows and five columns on the lower surface of the support member 10 to have an overall rectangular shape, but the microneedles 20, 20' may be arranged in various ways depending on the characteristics of the body part into which the microneedles 20, 20' are inserted, the properties of the drug to be delivered, the dosage and administration time, etc. Here, the support member may be made of a shape memory polymer, which will be described later.

[0054] Referring to (a) of FIG. 1, the microneedle 20 may have a first shape having a structure that has a high adhesive strength with the skin so that it can be stably fixed to the skin after being inserted into the skin.

[0055] Here, the microneedle 20 having the first shape may be composed of a body portion 22 and a head portion 24. The body portion 22 may have a cross section that becomes smaller toward the outside of the support member 10, that is, toward the lower side based on Fig. 1. The head portion 24 may extend from one side portion of the body portion 22, that is, the lower side based on Fig. 1, and may have a cross section larger than the cross section of one side portion of the body portion 22. Here, the head portion 24 may have a cross section that becomes smaller toward the tip.

[0056] Here, an outer skin layer (not shown) containing a pharmaceutical composition may be formed on the outer surface of the microneedle 20 having the first shape. With this, after the microneedle 20 is inserted into the skin, the outer skin layer dissolves due to body fluids, etc., and the pharmaceutical composition can be delivered to the inside of the body.

[0057] In addition, in order to deliver a pharmaceutical composition to the inside of the body, an injection port (not shown) may be formed at the end of the microneedle 20, and an injection tube (not shown) having one side connected to the injection port may be formed inside the microneedle 20. Here, a reservoir (not shown) connected to the other side of the injection tube and containing the pharmaceutical composition may further be included.

[0058] As a result, after the microneedle 20 is inserted into the skin, the pharmaceutical composition contained in the reservoir flows into the interior of the microneedle 20 through the injection tube and is then delivered to the interior of the body through the injection port.

[0059] In this embodiment, the first shape of the microneedle 20 is composed of the body portion 22 and the head portion 24 as described above, but the first shape may be composed of various shapes that have a high bonding strength with the skin so that the microneedle 20 can be stably fixed to the skin. For example, the first shape may be formed so that the end portion has a hook shape, the side portion has a sawtooth shape, or the entire shape has a zigzag shape.

[0060] Furthermore, in this embodiment, the multiple microneedles 20 may have the same first shape, or, if necessary, the multiple microneedles 20 may be configured to have first shapes that are different from one another.

[0061] More specifically, the plurality of microneedles 20 may include first and second microneedles, and the first shapes of the first and second microneedles may be different from each other.

[0062] The microneedles 20, 20' according to the first embodiment of the present invention may include polycaprolactone-polyglycidyl methacrylate (PCL-PGMA), which is a shape memory polymer.

[0063] Thus, the microneedles 20, 20' according to the first embodiment of the present invention can be transformed from a first shape to a second shape by a predetermined external stimulus due to the properties of the shape memory polymer. Here, the second shape refers to a shape having a structure with low adhesive strength to the skin so that the microneedles 20' can be easily removed from the skin.

[0064] Here, the shape memory polymer refers to a polymer that has the property of returning from a deformed shape to a shape before deformation by a certain external stimulus. In this specification, the term "biocompatibility" refers to the property of being substantially non-toxic to the human body, chemically inert, and non-immunogenic, and in this specification, the "biocompatible shape memory polymer" refers to a polymer having the above-mentioned property of "biocompatibility".

[0065] In this manner, the microneedle structure 1 according to the first embodiment of the present invention can prevent negative effects on the human body by using the microneedles 20, 20' made of a biocompatible shape-memory polymer.

[0066] In this embodiment, the shape memory polymer includes a biocompatible shape memory polymer, but the shape memory polymer may include at least one of a biodegradable shape memory polymer or a biocompatible shape memory polymer.

[0067] As used herein, the term "biodegradable" refers to the property of being decomposable by body fluids or microorganisms in the living body, and a "biodegradable shape-memory polymer" refers to a polymer having the aforementioned property of "biodegradability."

[0068] The shape memory polymer forming the microneedles 20, 20' according to the first embodiment of the present invention is made of polycaprolactone-polyglycidyl methacrylate (PCL-PGMA), but is not limited thereto.

[0069] Specifically, the shape memory polymer that can be used in the present invention may include at least one of segmented polyurethane, polycaprolactone copolymer, polylactide copolymer (poly(lactic acid)), crosslinked polyethylene, crosslinked polycaprolactone, crosslinked poly(lactic acid), crosslinked polyolefin, and polysiloxane.

[0070] In addition, the biocompatible or biodegradable shape-memory polymer that can be used in the present invention may include at least one of polycaprolactone with crosslinked acrylated end-groups, network structured polycaprolactone, polycaprolactone blend with polyurethane, cellulose grafted polycaprolactone, polycaprolactone-co-polysiloxane, multi-arm structured polycaprolactone, multi-arm structured poly(lactic acid), poly(lactic acid) copolymer, and poly(lactic acid)-co-poly(ethylene glycol) copolymer.

[0071] When the microneedles 20, 20' are made of a biodegradable shape-memory polymer, there is no need to remove the microneedles 20, 20' from the body after drug delivery, and since they are not completely absorbed by the body, even if any residue remains, they can be deformed into a second shape that has a low adhesive strength with the skin, and can therefore be easily removed from the skin.

[0072] In the following, the second shape will be described first, and then the predetermined external stimulus will be described.

[0073] Referring to FIG. 1(b), the second shape of the microneedle 20' may have a conical shape with a cross section that becomes smaller toward the outside of the support member 10, that is, toward the bottom with reference to FIG.

[0074] After the microneedle 20' having the second shape is inserted into the skin, the elastic force of the skin acts on the outside of the skin, and the adhesive force with the skin is weak, so that the microneedle 20' can easily fall off the skin.

[0075] In this embodiment, the second shape of the microneedle 20' is a cone shape as described above, but the second shape may be various shapes that have low bonding strength with the skin so that the microneedle 20' easily falls off from the skin.

[0076] Further, referring to both FIG. 1(a) and FIG. 1(b), the microneedles 20, 20' include a shape memory polymer, and are therefore capable of being transformed from a first shape to a second shape in response to an external stimulus due to the properties of the shape memory polymer.

[0077] The predetermined external stimulus can be determined by the physical and chemical properties of the shape memory polymer. In the first embodiment of the present invention, the external stimulus may include a temperature change. However, the external stimulus may also include ultraviolet radiation or energy transfer, depending on the properties of the shape memory polymer.

[0078] The temperature at which the microneedles 20, 20' change from the first shape to the second shape is defined as the reference temperature. That is, the microneedles 20, 20' may change shape gradually as the temperature changes around the reference temperature, and may have the first shape at a first temperature below the reference temperature and the second shape at a second temperature above the reference temperature.

[0079] Here, the reference temperature means a temperature at which the microneedles 20, 20' start to deform, but may also mean a temperature at which the microneedles 20, 20' are noticeably deformed or a temperature at which the microneedles 20, 20' start to deform rapidly. That is, the microneedles 20, 20' may start to deform before the microneedles 20, 20' reach the reference temperature.

[0080] The reference temperature can be determined by the characteristics of the shape-memory polymer that constitutes the microneedles 20, 20'. For example, a user can set the reference temperature to 28°C to 42°C by appropriately selecting the shape-memory polymer.

[0081] In addition, due to the characteristics of the shape-memory polymer that constitutes the microneedles 20, 20', when a thermal stimulus at a temperature significantly lower than a reference temperature is continuously applied for a long period of time, the shape of the microneedles 20, 20' can be gradually deformed.

[0082] Hereinafter, a process in which the microneedles are inserted into the skin and then removed using the microneedle structure according to the first embodiment of the present invention will be described in detail.

[0083] FIG. 2 is a diagram showing a process in which a microneedle is inserted into the skin by the microneedle structure according to the first embodiment of the present invention. FIG. 3 is a diagram showing a process in which a microneedle is inserted into the skin by the microneedle structure according to the first embodiment of the present invention, and then a predetermined stimulus is applied to the microneedle structure, and the microneedle is deformed from a first shape to a second shape. FIG. 4 is a diagram showing a process in which a microneedle is deformed into a second shape by the microneedle structure according to the first embodiment of the present invention, and then removed from the skin. FIG. 5 is a photograph of an experiment conducted to confirm fixation of a microneedle having a first shape according to the first embodiment of the present invention, where (a) of FIG. 5 is a photograph showing a state in which a microneedle is inserted into a hydrogel that mimics skin tissue, and (b) and (c) of FIG. 5 are photographs showing a process in which the microneedle is lifted outside the hydrogel using a microfiller.

[0084] The microneedle according to the first embodiment of the present invention may be formed so that it is inserted into the skin in a first shape having a high bonding strength with the skin, and is removed from the skin in a second shape having a low bonding strength with the skin.

[0085] 2(a), the microneedles 20 of the microneedle structure 1 according to the first embodiment of the present invention can be inserted into the skin 2 in a state in which the microneedle structure 1 has a first shape. To this end, a force can be applied to the upper surface of the support member 10 to press the microneedle structure 1 downward.

[0086] Referring to (b) of Figure 2, when a force is applied downward to the microneedle 20 of the microneedle structure 1 according to the first embodiment of the present invention, the end of the head portion 24 tears the tissue of the skin 2 and is inserted inside the skin 2.

[0087] Here, the skin 2 tissue to be torn by the head portion 24 can be in close contact with the outer circumferential surface of the body portion 22, which has a smaller cross section than the head portion 24, due to the elasticity of the skin 2. As a result, the upper side of the head portion 24 can be stably fixed by being engaged with the skin 2 tissue.

[0088] 2 and 5(a), the microneedle 20 having the first shape according to the first embodiment of the present invention was easily inserted into the hydrogel 2' by tearing the hydrogel 2' with its pointed end without being pressed with a large force. Then, due to the elasticity of the hydrogel 2', the internal tissue of the hydrogel 2' was wrapped around the body portion 22 of the microneedle 20 and adhered closely to it.

[0089] Referring to Figures 5(b) and 5(c), the microneedle 20 inserted inside the hydrogel 2' was pulled to the outside of the hydrogel 2', but the head portion 24 of the microneedle 20 was engaged with the internal tissue of the hydrogel 2' surrounding the body portion 22 and did not come out.

[0090] These results suggest that the microneedle 20 according to the first embodiment of the present invention can be easily inserted into the inside of the skin 2, and once inserted, it is fixed to the skin 2, allowing stable delivery of drugs into the body for the period of time desired by the user.

[0091] Referring to FIG. 3(a), an external stimulus A capable of inducing deformation of the shape memory polymer can be applied from the outside to the microneedle structure 1 according to the first embodiment of the present invention.

[0092] The time when the external stimulus A is applied can be selected by the user. For example, the time when the external stimulus A is applied can be the time when it is determined that the drug has been sufficiently administered into the skin 2 through the microneedle 20.

[0093] Here, as long as the shape deformation of the microneedle 20 can be induced, there are no particular limitations on the type, number of times, and time and method for applying the external stimulus A to the microneedle 20.

[0094] For example, the external stimulus A can be applied to the microneedle structure 1 in various ways, such as by hot air, hot water or heat conduction via a specified medium, to reach a reference temperature, a temperature adjacent to the reference temperature or a temperature lower than the reference temperature but at which deformation of the microneedle 20 begins.

[0095] 3(b) and 3(c), the microneedles 20, 20' can be deformed from a first shape to a second shape by applying an external stimulus A to the microneedle structure 1. Here, the external stimulus A may be applied continuously. Alternatively, the external stimulus A may be applied once or several times in a single burst.

[0096] 4(a), after the microneedles 20′ are transformed into the second shape, an external force may be applied to the microneedle structure 1 according to the first embodiment of the present invention to remove the microneedle structure 1 from the skin 2. Referring to FIG. 4(b), the second shape has a conical shape with a cross-sectional area that decreases toward the bottom, and therefore has a low bonding strength with the skin 2, allowing it to easily fall off from the skin 2.

[0097] More specifically, the skin 2 pushes the microneedle 20' in a direction perpendicular to the outer peripheral surface of the microneedle 20' in order to restore the portion 2a torn by the microneedle 20', so that the microneedle 20' having the second shape is pushed outward more easily by the elastic force of the skin 2.

[0098] In this way, the microneedle structure 1 according to the first embodiment of the present invention is inserted into the skin 2 with the microneedles 20, 20' having a first shape with high binding strength with the skin 2, so that they are stably fixed to the skin 2 and can deliver drugs, and falls off from the skin 2 with a second shape with low binding strength with the skin 2, so that they can be easily removed from the skin 2.

[0099] In addition, the microneedle structure 1 according to the first embodiment of the present invention can determine or adjust the time at which the microneedles 20, 20' are removed from the skin 2 by controlling the reference temperature at which deformation begins by appropriately selecting a shape memory polymer and by controlling the time at which a thermal stimulus is applied to reach the reference temperature.

[0100] Hereinafter, the microneedle structures according to the second and third embodiments of the present invention will be described. Here, since the configurations other than the support member and the second shape of the microneedle of the microneedle structures according to the second and third embodiments of the present invention may be the same as those of the first embodiment, detailed description thereof will be omitted, and the support member and the second shape of the microneedle according to the second and third embodiments of the present invention will be described.

[0101] Figure 6 is a perspective view of a microneedle structure according to a second embodiment of the present invention, where (a) of Figure 6 is a diagram showing a state in which the microneedle has a first shape, and (b) of Figure 6 is a diagram showing a state in which the microneedle has a second shape.

[0102] 6, the support member 110 of the microneedle structure 101 according to the second embodiment of the present invention may be made of materials other than shape memory polymers. For example, the support member 110 may be made of any known material such as medical tape, adhesive tape or other types of polymers.

[0103] In addition, the material of the support member 110 may be selected according to the physicochemical properties of the shape memory polymer of the microneedles 120, 120'. For example, when the shape memory polymer changes shape due to thermal stimulation, the support member 110 may be configured to induce fast deformation of the microneedles 120, 120' by selecting a material with high heat transfer efficiency. Conversely, the support member 110 may be configured to induce slow deformation of the microneedles 120, 120' by selecting a material with low heat transfer efficiency.

[0104] In this way, the microneedle structure 101 according to the second embodiment of the present invention can maximize the effect of the microneedles 120, 120' being able to stably deliver drugs into the body while being easily removed from the skin by appropriately selecting the material constituting the support member 110 depending on the body part and environment to which the microneedles 120, 120' are applied.

[0105] Figure 7 is a perspective view of a microneedle structure according to a third embodiment of the present invention, where (a) of Figure 7 is a diagram showing a state in which the microneedle has a first shape, and (b) of Figure 7 is a diagram showing a state in which the microneedle has a second shape.

[0106] Referring to FIG. 7(a), a microneedle structure 201 according to a third embodiment of the present invention may be configured identically to the first embodiment, with the microneedles 220 having a first shape.

[0107] Referring to FIG. 7( b ), the second shape of the microneedle 220 ′ of the microneedle structure 201 according to the third embodiment of the present invention may be formed flat so as to be parallel to one surface of the support member 210 .

[0108] Here, the thickness t' of the microneedle structure 201 when the microneedles 220' are in the second shape may be thicker than the thickness t of the support member 210 when the microneedles 220 are in the first shape. More specifically, the thickness t' of the microneedle structure 201 may be made up of the thickness t1' of the support member 210 and the thickness t2' of the microneedles 220' in the second shape.

[0109] Here, the second shape being formed flat so as to be parallel to one surface of the support member 210 means that the second shape does not protrude below the support member 210, or even if it has a slightly protruding shape, the protruding portion includes a plane parallel to the outer surface of the skin into which the microneedles 220, 220' are inserted, and has a shape that can be easily removed from the skin.

[0110] In addition, the second shape of the microneedle 220' may have a shape that protrudes slightly from one side of the support member 210, and the protruding portion may be formed with a curved surface having a very large curvature so that it is difficult to insert into the skin, and therefore may have a shape that has a low adhesive strength with the skin and can easily fall off.

[0111] As a result, the microneedle structure 201 according to the third embodiment of the present invention may be formed such that the microneedles 220, 220' fall off the skin by themselves during the process of transforming from the first shape to the second shape, since the second shape of the microneedle 220' includes a plane facing the skin.

[0112] Therefore, the microneedle structure 201 according to the third embodiment of the present invention can be easily removed from the skin even if no external force is applied to remove the microneedles 220, 220' from the skin.

[0113] A method for manufacturing a microneedle structure according to an embodiment of the present invention will be described below.

[0114] Fig. 8 is a flow chart of the method for manufacturing a microneedle structure according to the embodiment of the present invention.Figs. 9a to 9d are views for explaining the method for manufacturing a microneedle structure according to the first embodiment of the present invention.

[0115] Referring to Figures 8 and 9a, the manufacturing method of a microneedle structure according to the first embodiment of the present invention is a method for manufacturing a microneedle structure according to the first embodiment of the present invention, in which after preparing a shape memory polymer 9 (S10), the prepared shape memory polymer 9 is applied to a mold 5 for a second shape (S20).

[0116] Here, the shape memory polymer 9 is a copolymer of caprolactone and glycidyl methacrylate, and may be made of polycaprolactone-polyglycidyl methacrylate (PCL-PGMA).

[0117] 9a, a second shape intaglio 5a corresponding to the second shape may be formed on the upper surface of the second shape mold 5. Here, the second shape intaglio 5a may be formed in a plurality on the upper surface of the second shape mold 5 corresponding to the arrangement of a plurality of microneedles.

[0118] The second shape mold 5 may be made of various materials. For example, the second shape mold 5 may be made of polydimethylsiloxane (PDMS) as an ultraviolet curable resin, but is not limited to this.

[0119] Further referring to Figure 9a, in the manufacturing method of a microneedle structure according to the first embodiment of the present invention, after a shape memory polymer 9 is applied to a second shape mold 5 (S20), an intermediate member 4 can be placed on the upper side of the shape memory polymer 9 so that the upper side of the shape memory polymer 9 can be pressed flat by heat transfer.

[0120] Here, the intermediate member 4 may be a plate-shaped member having a predetermined thickness. The intermediate member 4 is preferably made of a material capable of transferring heat and enduring large pressure. For example, the intermediate member 4 may be made of glass, but is not limited thereto.

[0121] Referring to Figures 8, 9a and 9b, in the manufacturing method of a microneedle structure according to the first embodiment of the present invention, an intermediate member 4 is placed on the upper side of a shape memory polymer 9, and then pressure is applied (S30) to mold the microneedle 20' into a second shape (S40).

[0122] Here, a predetermined stimulus B may be applied together with the pressure. The predetermined stimulus B can be determined by a process of forming a second shape of the shape memory polymer 9. In this embodiment, the process of forming a second shape is a thermal crosslinking process, and the predetermined stimulus B includes heat transfer.

[0123] For this purpose, a thermal crosslinking initiator may be mixed into the shape-memory polymer 9. For example, at least one of potassium persulfate, ammonium persulfate, benzoyl peroxide, dilauroyl peroxide, dicumyl peroxide, hydrogen peroxide, and azobisisobutyronitrile may be mixed into the shape-memory polymer 9, but is not limited thereto, and various known thermal crosslinking initiators may be used.

[0124] Here, the amount of the thermal crosslinking initiator mixed into the shape-memory polymer 9 may have a weight ratio of 1% to 5% with respect to the weight ratio of polycaprolactone-polyglycidyl methacrylate.

[0125] As previously described in the microneedle structure according to the first embodiment of the present invention, the shape memory polymer in the present invention is not limited to polycaprolactone-polyglycidyl methacrylate, but may include at least one of various known shape memory polymers, biocompatible shape memory polymers, and biodegradable shape memory polymers.

[0126] 9b, the shape memory polymer 9 may be heated and compressed for a predetermined time by a hot press plate 3. That is, a predetermined stimulus B may be applied by the hot press plate 3. Here, the hot press plate 3 preferably heats both sides of the shape memory polymer 9.

[0127] More specifically, the thermal compressor 3 is placed below the second shape mold 5 and above the intermediate member 4, and then the shape memory polymer 9 can be heated and compressed by applying pressure in the direction of approaching each other.

[0128] Here, the thermal compressor 3 can proceed with a process of heating the shape-memory polymer 9 at 80°C to 120°C for about 15 minutes and applying a pressure of 5 MPa to 20 MPa. More preferably, the thermal compressor 3 can proceed with a process of heating the shape-memory polymer 9 at 90°C to 110°C and applying a pressure of 13 MPa to 17 MPa.

[0129] Then, the microneedle 20' is molded into a second shape (S40). Referring further to FIG. 9b, a part of the shape memory polymer 9 can be compressed by the thermal compressor 3 to be pressed into the inside of the second shape intaglio 5a of the second shape mold 5. The rest of the shape memory polymer 9 can spread on the upper surface of the second shape mold 5 around the second shape intaglio 5a to form a support member 10 having a predetermined thickness.

[0130] At the same time, the shape memory polymer 9 can undergo a thermal crosslinking reaction by a predetermined externally applied stimulus B. This forms the support member 10, and the microneedle 20′ having the second shape can be formed on one surface of the support member 10.

[0131] Thereafter, a step of removing the thermal crosslinking initiator mixed in the shape memory polymer 9 may be further performed. Here, the thermal crosslinking initiator mixed in the shape memory polymer 9 may be removed by washing with water or wind.

[0132] In this embodiment, the microneedle 20' is formed by a thermal crosslinking reaction, but may be formed by a reaction other than a thermal crosslinking reaction. For example, the microneedle 20' may be formed by a photocrosslinking reaction.

[0133] Here, a photocrosslinking initiator can be mixed into the shape-memory polymer 9. For example, the shape-memory polymer 9 can be mixed with at least one of Darocure, Irgacure, and LAP (Lithium phenyl-2,4,6-trim ethylbenzoylphosphinate), TPO (Diphenyl(2,4,6-Trimethylbenzoyl)Phosphine), and TPO-L (Ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate), each of which has a hydroxymethylpropiophenone structure, but is not limited thereto.

[0134] Here, the predetermined stimulus B may be ultraviolet light, and the intermediate member 4 may be made of a material such as glass through which ultraviolet light can pass. The predetermined stimulus B may be ultraviolet light having a wavelength of about 365 nm emitted by a UV lamp, and may be irradiated for about 200 seconds.

[0135] As described above, the manufacturing method of the microneedle structure according to the embodiment of the present invention can reduce the reference temperature at which the microneedle 20' is transformed into the second shape by forming the microneedle 20' into the second shape using a thermal crosslinking reaction or a photocrosslinking reaction.

[0136] Specifically, when the microneedle 20' is molded without using thermal crosslinking or photocrosslinking reaction, the reference temperature may be about 30°C to 48°C, but when the microneedle 20' is molded using thermal crosslinking or photocrosslinking reaction, the reference temperature can be reduced to about 28°C to 42°C.

[0137] As a result, the manufacturing method of the microneedle structure according to an embodiment of the present invention can set the reference temperature at which the microneedle 20' transforms from a first shape to a second shape to suit the body by molding the microneedle 20' into a second shape using a thermal crosslinking or photocrosslinking reaction.

[0138] 8 and 9c, in the method for manufacturing a microneedle structure according to the first embodiment of the present invention, after forming a second shape (S40), the microneedle 20' is placed inside the first shape intaglio 6a of the first shape mold 6 (S50). Then, the temperature of the microneedle 20' is adjusted to a variable temperature (S60).

[0139] More specifically, a first shape intaglio 6a corresponding to the first shape may be formed on the upper surface of the first shape mold 6. Here, the first shape intaglio 6a may be formed in a plurality of pieces corresponding to the arrangement of the plurality of microneedles 20'.

[0140] The first shape mold 6 may be made of various materials. For example, the first shape mold 6 may be made of polydimethylsiloxane as an ultraviolet curable resin, but is not limited to this.

[0141] The microneedle 20' disposed in the first shape recess 6a of the first shape mold 6 may undergo a heat transfer process to have a variable temperature. Here, the variable temperature refers to a temperature at which the microneedle 20' molded into the second shape can be molded into another shape, and in this embodiment, the variable temperature may be a temperature of 42°C or higher.

[0142] 8 and 9d, in the method for manufacturing a microneedle structure according to the first embodiment of the present invention, after adjusting the temperature to a variable temperature (S60), the microneedle 20' is pressed against the inside of the indentation 6a for the first shape (S70) and molded into a first shape (S80). That is, the microneedle 20' can be molded from the second shape to the first shape by being pressed against the inside of the indentation 6a for the first shape by an external force.

[0143] Thereafter, in the manufacturing method of the microneedle structure according to the first embodiment of the present invention, the microneedle structure 1 is cooled and then maintained at a low temperature for a predetermined time (S90), thereby fixing the shape of the microneedles 20 in the first shape.

[0144] Here, the cooling process may be a rapid cooling process, and the low temperature state may be achieved by maintaining the microneedle structure 1 at 0° C. or below. The cooling process and the low temperature maintaining process may be achieved using a cooler, ice, liquefied nitrogen, or the like.

[0145] In this manner, the manufacturing method for the microneedle structure according to the first embodiment of the present invention can manufacture the microneedle structure 1 according to the first embodiment of the present invention.

[0146] The following describes the manufacturing methods of the microneedle structure according to the second and third embodiments of the present invention. Here, the same contents as those in the first embodiment of the present invention will be omitted, and the description will focus on the differences from the first embodiment.

[0147] 10a to 10e are views for explaining a manufacturing method of a microneedle structure according to the second embodiment of the present invention.

[0148] 8, 10a and 10b, in the method for manufacturing a microneedle structure according to the second embodiment, a shape memory polymer 9' is applied onto a second shape mold 5 (S10, S20), and then an intermediate member 4 is placed on the upper side of the applied shape memory polymer 9', and the shape memory polymer 9' is compressed using a thermal compressor 3 (S40). As a result, the shape memory polymer 9' is pressed into the inside of the second shape intaglio 5a.

[0149] Then, a predetermined stimulus B is applied to the shape-memory polymer 9' to cause a cross-linking reaction, thereby forming the microneedle 120' into a second shape (S50). Here, if the cross-linking reaction is a thermal cross-linking reaction, the predetermined stimulus B may be heat transfer by a thermal compressor 3, and if the cross-linking reaction is a photo-cross-linking reaction, the predetermined stimulus B may be ultraviolet light irradiated by a UV lamp. Here, the shape-memory polymer 9' is pressed into the inside of the intaglio 5a for the second shape, thereby forming a plurality of microneedles 120' separated from each other into the second shape.

[0150] 10c, the microneedles 120' molded into the second shape are disposed inside the first shape intaglios 6a formed on one surface of the first shape mold 6 (S50). Here, an adhesive member 126' may be disposed on the upper side of the microneedles 120'.

[0151] Here, the adhesive member 126' may be made of various materials having adhesive strength capable of attaching the supporting member and the microneedle 120' described below. In this embodiment, the adhesive member 126' may be made of photoresist epoxy that can be cured by ultraviolet light to have adhesive strength, but is not limited thereto. For example, the adhesive member 126' may be made of industrial glue or medical adhesive.

[0152] Referring to Figures 8 and 10d, in the manufacturing method of a microneedle structure according to the second embodiment of the present invention, after adjusting the temperature of the microneedle 120' to a variable temperature (S60), the microfiller 7 presses the microneedle 120' against the inside of the indentation 6a for the first shape (S70), and the microneedle 120' is molded into the first shape (S80).

[0153] Then, referring to FIG. 10e, in the second embodiment of the present invention, after the support member 110 is disposed on the top of the microneedle 120, a process of attaching the support member 110 and the microneedle 120 is performed.

[0154] Here, the support member 110 may be made of a material different from the material constituting the microneedle 120. For example, the support member 110 may be a medical tape, a general adhesive tape, or a member made of various polymers.

[0155] Thereafter, the support member 110 and the microneedles 120 formed into the first shape are cooled and then maintained at a low temperature (S90), so that the shape of the microneedles 120 can be fixed in the first shape.

[0156] As described above, the manufacturing method of the microneedle structure according to the second embodiment of the present invention can manufacture the microneedle structure 101 according to the second embodiment of the present invention.

[0157] 11a to 11d are views illustrating a manufacturing method of a microneedle structure according to the third embodiment of the present invention.

[0158] 8, 11a and 11b, in the manufacturing method of the microneedle structure according to the third embodiment, a shape memory polymer 9" is placed on a mold for a second shape 5' (S10, S20), and then an intermediate member 4 is placed on top of the placed shape memory polymer 9" and the shape memory polymer 9" is compressed using a thermal compressor 3 (S40). As a result, the shape memory polymer 9" is pressed into the inside of the intaglio mold for a second shape 5a'.

[0159] Here, the second shape intaglio 5a' of the second shape mold 5' may include an opening that is open upward and has a wide width, and a bottom surface that is a flat plane. The second shape intaglio 5a' may be formed to a depth greater than or equal to the thickness of the support member 210 and the second shape 220' that will ultimately be formed.

[0160] Then, a predetermined stimulus B is applied to the shape memory polymer 9" to cause a crosslinking reaction, thereby forming a portion of the shape memory polymer 9" into a second shape 220' (S50). Here, if the crosslinking reaction is a thermal crosslinking reaction, the predetermined stimulus B may be heat transfer by a thermal compressor 3, and if the crosslinking reaction is a photocrosslinking reaction, the predetermined stimulus B may be ultraviolet light irradiated by a UV lamp. Here, the upper part of the shape memory polymer 9" may form the support member 210, and the lower part may form the second shape 220' of the microneedle.

[0161] Referring to Figures 8 and 11c, in the manufacturing method of a microneedle structure according to the third embodiment of the present invention, after placing the support member 210 and the second shape 220' of the microneedle on the upper side of the mold 6 for the first shape (S50), the temperature of the support member 210 and the second shape 220' of the microneedle is adjusted to a variable temperature (S60).

[0162] Here, a probe 8 may be disposed on the upper side of the support member 210. A plurality of microfillers 8a may be provided on the lower side of the probe 8 in correspondence with a plurality of first shape intaglios 6a formed on the upper surface of the first shape mold 6.

[0163] 11d, the microfiller 8a of the probe 8 presses the second shape 220′ of the microneedle against the inside of the intaglio 6a for the first shape (S70), and the microneedle is molded into the first shape 220 (S80). Then, the support member 210 and the microneedle molded into the first shape 220 are cooled and maintained at a low temperature (S90), and the shape of the microneedle can be fixed into the first shape 220.

[0164] In this manner, the manufacturing method of the microneedle structure according to the third embodiment of the present invention can manufacture the microneedle structure 201 according to the third embodiment of the present invention.

[0165] Figure 12 is a photograph showing a microneedle structure array manufactured by a microneedle structure manufacturing method according to an embodiment of the present invention, where (a) of Figure 12 is a photograph of a microneedle structure formed into a second shape by one step of the manufacturing method according to this embodiment, (b) of Figure 12 is a photograph of the microneedle structure before an external stimulus is applied, and (c) of Figure 12 is a photograph of the microneedle structure whose shape has been deformed after an external stimulus is applied.

[0166] Referring to Figures 12(a) to 12(c), it can be seen that the manufacturing method of a microneedle structure according to one embodiment of the present invention makes it possible to manufacture a microneedle structure that is configured to deform from a first shape to a second shape in response to an external stimulus.

[0167] As described above, the microneedles and microneedle structures and their manufacturing methods according to the embodiments of the present invention are inserted into the skin in a state in which the microneedle has a shape that has a high adhesive strength with the skin, and then removed from the skin in a state in which the microneedle has been deformed into a shape that has a low adhesive strength with the skin, utilizing the properties of the shape-memory polymer. This makes it possible to provide microneedles that can be stably fixed to the skin and easily removed from the skin when a drug is administered into the body.

[0168] Although an embodiment of the present invention has been described above, the concept of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the concept of the present invention can easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same concept, which can also be said to fall within the scope of the concept of the present invention.

Claims

1. A microneedle structure including a microneedle to be inserted into the skin, A microneedle including a shape memory polymer and formed so as to be deformable from a first shape to a second shape in response to a predetermined external stimulus due to the properties of the shape memory polymer; A microneedle structure comprising: a support member having one surface on which the microneedles are formed.

2. The first shape is A body portion having a cross section that becomes smaller toward one side; The microneedle structure according to claim 1 , further comprising: a head portion extending from one side of the body portion and having a cross section larger than the cross section of the one side of the body portion.

3. The microneedle structure according to claim 2 , wherein the head portion has a cross section that becomes smaller toward the tip.

4. The microneedle structure of claim 1 , wherein the second shape is a cone shape.

5. The microneedle structure according to claim 1 , wherein the second shape is formed flat on the one surface of the support member.

6. The microneedle is being inserted into the skin while having the first shape; The shape of the device is changed from the first shape to the second shape when the device is inserted into the skin, The microneedle structure of claim 1 , configured to be removed from the skin while having the second shape.

7. An outer skin layer is formed on the outer surface of the microneedle, The microneedle structure of claim 1 , wherein the outer skin layer comprises a pharmaceutical composition.

8. An injection port is formed at the end of the microneedle, An injection tube is formed inside the microneedle, one side of which is connected to the injection port, The microneedle structure according to claim 1 , further comprising a reservoir connected to the other side of the injection tube and containing a pharmaceutical composition.

9. The microneedle structure according to claim 1 , wherein the predetermined stimulus includes at least one of a temperature change or ultraviolet light irradiation.

10. The microneedle structure of claim 1 , wherein the shape memory polymer comprises at least one of a biodegradable shape memory polymer or a biocompatible shape memory polymer.

11. The biocompatible shape-memory polymer includes polycaprolactone with crosslinked acrylated end-group, network structured polycaprolactone, polycaprolactone blended with polyurethane, and cellulose grafted polycaprolactone. The microneedle structure according to claim 10, comprising at least one of polycaprolactone, a copolymer of polycaprolactone and polysiloxane (polycaprolactone-co-polysiloxane), a multi-arm structured polycaprolactone (multi-arm structured polycaprolactone), a multi-arm structured polylactic acid (multi-arm structured poly(lactic acid)), a poly(lactic acid) copolymer, and a copolymer of polylactic acid and polyethylene glycol (poly(lactic acid)-co-poly(ethylene glycol)).

12. the predetermined stimulus includes a temperature change; The microneedle structure of claim 11, wherein the microneedle gradually deforms as the temperature changes around a reference temperature, and has a first shape at a first temperature below the reference temperature and a second shape at a second temperature above the reference temperature.

13. The microneedle structure according to claim 12, wherein the reference temperature is 28°C to 42°C.

14. The microneedle is a plurality of microneedles, The microneedle structure according to claim 1 , wherein the plurality of microneedles are regularly arranged at regular intervals.

15. the plurality of microneedles includes first and second microneedles; The microneedle structure according to claim 14 , wherein the first shape of the first microneedle and the first shape of the second microneedle have different shapes from each other.

16. A method for manufacturing a microneedle structure, the method comprising: a microneedle including a shape memory polymer, the microneedle being deformable from a first shape to a second shape in response to a predetermined external stimulus due to properties of the shape memory polymer; and a support member having the microneedle formed on one surface thereof, forming a microneedle having the second shape using a shape memory polymer; adjusting the temperature such that the microneedles having the second shape are variable; and forming the microneedle such that the temperature-adjusted microneedle has the first shape.

17. The step of forming the second shape includes: applying the shape memory polymer onto one surface of a second shape mold having a second shape intaglio corresponding to the second shape; The method for manufacturing a microneedle structure according to claim 16, further comprising: applying pressure so that a portion of the shape memory polymer flows into the inside of the intaglio for the second shape.

18. The step of forming the second shape includes: The method for manufacturing a microneedle structure described in claim 17 includes a step of applying pressure to the shape memory polymer, so that the remaining portion of the shape memory polymer except for the part spreads onto the one surface of the mold for the second shape centered on the intaglio for the second shape to form a support member.

19. The step of forming the second shape includes: mixing the shape memory polymer with a thermal crosslinking initiator; A method for producing a microneedle structure according to claim 17, comprising the step of applying heat to the shape memory polymer.

20. The method for producing a microneedle structure according to claim 19, wherein the thermal crosslinking initiator includes at least one of potassium persulfate, ammonium persulfate, benzoyl peroxide, dilauroyl peroxide, dicumyl peroxide, hydrogen peroxide, and azobisisobutyronitrile.

21. The step of forming the second shape includes: mixing the shape memory polymer with a photocrosslinking initiator; A method for producing a microneedle structure according to claim 17, comprising the step of: applying ultraviolet light to the shape memory polymer.

22. The method for producing a microneedle structure according to claim 21, wherein the photocrosslinking initiator includes at least one of Darocure, Irgacure, LAP (lithium phenyl-2,4,6-trim ethylbenzoylphosphinate) having a phenyl phosphine structure, TPO (diphenyl(2,4,6-trimethylbenzoyl)phosphine), and TPO-L (ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate).

23. The step of forming the first shape includes: disposing the microneedle having the second shape in a first shape depression formed on one surface of a first shape mold to correspond to the first shape; The method for manufacturing a microneedle structure according to claim 16, further comprising: pressing the microneedle against the inside of the intaglio for the first shape.

24. After forming the first shape, The method for manufacturing a microneedle structure according to claim 23, comprising the step of cooling the microneedle to a low temperature so as to fix the first shape of the microneedle, and then maintaining the cooled state.

25. After forming the first shape, The method of claim 16, further comprising attaching the microneedle having the first shape to a support member.

26. The step of forming the first shape includes: disposing the microneedle having the second shape in a first shape depression formed on one surface of a first shape mold to correspond to the first shape; applying an adhesive material to one side of the microneedle; and pressing the microneedle against the inside of the intaglio for the first shape.

Images