Patent Publication Number: US-2021170154-A1

Title: Perforated plate microstructure module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of International Patent Application No. PCT/KR2019/010876, filed on Aug. 27, 2019, which is based upon and claims the benefit of priority to Korean Patent Application Nos. 10-2018-0101288 and 10-2018-0101293 filed with the Korean Intellectual Property Office on Aug. 28, 2018. The disclosures of the above-listed applications are hereby incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a perforated plate microstructure module, and more particularly, to a perforated plate microstructure module which can be used to deliver a drug into the skin. 
     BACKGROUND ART 
     In general, tablets or capsules are orally administered or injection needles are used to deliver drugs for treatment of diseases or cosmetic products into a body. Recently, various microstructures including microneedles have been developed. The microstructures developed up to date have been mainly used to deliver a drug into a living body, collect blood, and detect analytes in the body. 
     A biodegradable microneedle in the related art is not dissolved immediately when the biodegradable microneedle is inserted into the skin, but the biodegradable microneedle is dissolved completely depending on the used substance, and it takes several minutes to several tens of minutes to dissolve the biodegradable microneedle. Therefore, a patch, which may be fixed to the skin, is used to prevent the microneedle from being separated from the skin while the microneedle is dissolved in the skin after being inserted into the skin. 
     However, in the process of inserting the microneedle using the patch, there are problems such as skin irritation caused by attachment and detachment of the patch, limitations in amount of loaded drug due to a small size of the microneedle, difficulty in delivering a drug in accurate quantity due to residues remaining on the patch after dissolution of the microneedle, a deterioration in insertion rate of the microneedle caused when human hair pushes the patch from the skin on which the human hair exists and the human hair interrupts adhesion between the patch and the skin, and difficulty in attaching the patch onto a curved portion of the skin, such as a wrinkle or a join, or a moving portion. 
     Meanwhile, in order to apply the microneedle to a shooting device for inserting the microneedle into the skin, the microneedles are manufactured on a biodegradable film, and only the biodegradable film on which the microneedles exist is separated and sized to be suitable for a perforated plate. The film having the adjusted size is placed and mounted on the perforated plate having openings corresponding to the microneedles, and a pillar is used to push the microneedles, thereby inserting the microneedles into the skin. 
     The shooting device in the related art may completely implant the microstructure into the skin, but the perforated layer is in contact with the skin when the microstructure is implanted, and the pillar is also inserted into the skin when the pillar pushes the microstructure. In particular, because the perforated layer and the pillar of the shooting device in the related art are integrally formed, it is difficult to replace the perforated layer and the pillar. 
     Therefore, when the shooting device is reused, the perforated layer and the pillar, which were in contact with the skin during previous use, come into contact with another subject&#39;s skin, which causes a hygienic problem such as secondary infection. 
     In order to solve the above-mentioned problem, there is an increasing need for a microstructure module capable of preventing a part, which is to be in contact with the skin, from being reused, and limiting the use of the part to a single use. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     The present invention has been made in an effort to solve the above-mentioned problems in the related art, and an object of the present invention is to provide a perforated plate microstructure module which is easily replaced to limit use of a part, which is to be in contact with or inserted into skin, in a single use. 
     Another object of the present invention is to provide a perforated plate microstructure module capable of providing a constant administration amount of drug to be delivered into the skin and increasing the administration amount of drug. 
     Technical Solution 
     A perforated plate microstructure module according to the present invention includes: a perforated plate having one or more openings; base parts provided in the one or more openings; microneedles provided on the base parts; and a pressing member positioned to be spaced apart from the perforated plate and including one or more pillars provided to press the base parts, in which the base part and the perforated plate coupled are separable by force of 0.01 N to 100 N. 
     The base part and the microneedle may contain different compositions. 
     The base part and the microneedle may contain the same composition. 
     The opening may be convex inward. 
     The base part may fill a part or the entirety of an interior of the opening so that the microneedle is positioned on the base part. 
     The base part may be 1% to 100% of a height of the perforated plate. 
     The base part may contain hyaluronic acid. 
     The base part may contain triamcinolone. 
     The microneedle may contain a medicinally active ingredient. 
     The coupling force between the base part and the perforated plate may be adjusted by one or more of a material of the perforated plate, a material of the base part, a height of the base part, and plasma surface treatment. 
     The one or more pillars and the base part may be in contact with one another or spaced apart from one another at an interval of 1 cm or less. 
     The base part or the microneedle may contain a biodegradable substance. 
     The biodegradable or biocompatible substance may be polyester, polyhydroxyalkanoate (PHAs), poly(α-hydroxyacid), poly(β-hydroxyacid), poly(3-hydroxybutyrate-co-valerate; PHBV), poly(3-hydroxyproprionate; PHP), poly(3-hydroxyhexanoate; PHH), poly(4-hydroxyacid), poly(4-hydroxybutyrate), poly(4-hydroxyvalerate), poly(4-hydroxyhexanoate), poly(ester amide), polycaprolactone, polylactide, polyglycolide, poly(lactide-co-glycolide; PLGA), polydioxanone, polyorthoester, polyetherester, polyanhydride, poly(glycolic acid-co-trimethylene carbonate), polyphosphoester, polyphosphoester urethane, poly(amino acid), polycyanoacrylate, poly(trimethylene carbonate), poly(imino carbonate), poly(tyrosine carbonate), polycarbonate, poly(tyrosine arylate), polyalkylene oxalate, polyphosphazene, PHA-PEG, ethylene vinyl alcohol copolymer (EVOH), polyurethane, silicone, polyester, polyolefin, polyisobutylene and ethylene-alphaolefin copolymer, styrene-isobutylene-styrene triblock copolymer, acrylic polymer and copolymer, vinyl halide polymer and copolymer, polyvinyl chloride, polyvinyl ether, polyvinyl methyl ether, polyvinylidene halide, polyvinylidene fluoride, polyvinylidene chloride, polyfluoro alkene, polyperfluoroalkene, polyacrylonitrile, polyvinyl ketone, polyvinyl aromatics, polystyrene, polyvinyl ester, polyvinyl acetate, ethylene-methyl methacrylate copolymer, acrylonitrile-styrene copolymer, ABS resin and ethylene-vinyl acetate copolymer, polyamide, alkyd resin, polyoxymethylene, polyimide, polyether, polyacrylate, polymethacrylate, polyacrylic acid-co-maleic acid, chitosan, dextran, cellulose, heparin, hyaluronic acid, alginate, inulin, starch, or glycogen, and particularly, may contain one or more substances selected from polyester, polyhydroxyalkanoate (PHAs), poly(α-hydroxyacid), poly(β-hydroxyacid), poly (3-hydrosoxybutyrate-co-valerate; PHBV), poly(3-hydroxyproprionate; PHP), poly(3-hydroxyhexanoate; PHH), poly(4-hydroxyacid), poly(4-hydroxybutyrate), poly(4-hydroxyvalerate), poly(4-hydroxyhexanoate), poly(ester amide), polycaprolactone, polylactide, polyglycolide, poly(lactide-co-glycolide; PLGA), polydioxanone, polyorthoester, polyether ester, polyanhydride, poly(glycolic acid-co-trimethylene carbonate), polyphosphoester, polyphosphoester urethane, poly(amino acid), polycyano acrylate, poly(trimethylene carbonate), poly(imino carbonate), poly(tyrosine carbonate), polycarbonate, poly(tyrosine arylate), polyalkylene oxalate, polyphosphazene, PHA-PEG, chitosan, dextran, cellulose, heparin, hyaluronic acid, alginate, inulin, starch, and glycogen. 
     The perforated plate or the base part may be made of a hydrophilic material. 
     Advantageous Effects 
     According to the perforated plate microstructure module according to the exemplary embodiment of the present invention, the perforated layer and the pillar, which are to be in contact with or inserted into the skin, are provided in the integrated module, such that the perforated plate microstructure module may be replaced and discarded after single use, thereby preventing a hygienic problem such as secondary infection. 
     The perforated plate microstructure module according to the exemplary embodiment of the present invention may implant the microstructure without an adhesive sheet, such that the perforated plate microstructure module may be used for a curved or frequently moving joint area, thereby minimizing the restriction of the implantation site. 
     According to the shooting microstructure module according to another exemplary embodiment of the present invention, the microstructure is completely implanted in the skin, such that an accurate amount of drug may be delivered, thereby improving an efficacy of delivering the drug and safety and uniformity in using the drug. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating a configuration of a perforated plate microstructure module according to an exemplary embodiment of the present invention. 
         FIG. 2  is a cross-sectional view illustrating the perforated plate microstructure module according to the exemplary embodiment of the present invention. 
         FIG. 3  is a cross-sectional view illustrating a state in which microneedles are inserted into skin by a pressing member according to the exemplary embodiment of the present invention. 
         FIG. 4  is a cross-sectional view illustrating a state in which the perforated plate microstructure module according to the exemplary embodiment of the present invention is returned back to an original state after the microneedles are inserted into the skin. 
         FIG. 5  is a perspective view illustrating a state in which a shooting microstructure module according to another exemplary embodiment of the present invention is mounted on an applicator. 
         FIG. 6  is a cross-sectional view illustrating the shooting microstructure module side illustrated in  FIG. 5 . 
         FIG. 7  is a perspective view illustrating a housing and a perforated layer illustrated in  FIG. 6 . 
         FIG. 8  is a perspective view illustrating the pressing member illustrated in  FIG. 6 . 
         FIG. 9  is a cross-sectional view illustrating a state in which the applicator illustrated in  FIG. 6  performs shooting. 
         FIG. 10  is a cross-sectional view illustrating a state in which the microneedles illustrated in  FIG. 9  are separated. 
         FIG. 11  is a cross-sectional view illustrating a state in which the microstructure module illustrated in  FIG. 10  is separated from the applicator. 
         FIG. 12  is a cross-sectional view illustrating an example in which the shooting microstructure module according to another exemplary embodiment of the present invention is coupled to the applicator. 
         FIG. 13  is a cross-sectional view illustrating another example in which the shooting microstructure module according to another exemplary embodiment of the present invention is coupled to the applicator. 
         FIG. 14  is a cross-sectional view illustrating still another example in which the shooting microstructure module according to another exemplary embodiment of the present invention is coupled to the applicator. 
         FIG. 15  is a graph illustrating experimental results of measuring coupling forces between perforated plates and base parts in a Comparative Example and Experimental Examples 1 to 5. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS 
     
         
         
           
               100 : Perforated plate microstructure module 
               110 : Perforated plate 
               111 : Opening 
               120 : Base part 
               130 : Microneedle 
               140 : Pressing member 
               141 : Pillar 
               20 : Applicator 
               21 : Main body housing 
               22 : Pushing member 
               23 : Piston 
               24 : Screw thread 
               200 : Shooting microstructure module 
               210 : Housing 
               220 : Perforated layer 
               222 : Opening 
               224 : Support part 
               230 : Shooting microstructure 
               232 : Base part 
               234 : Microneedle 
               240 : Pressing member 
               241 ,  242 : Plate 
               244 : Pillar 
               246 : Catching part 
               248 : Through port 
               251 ,  252 ,  253 : Coupling member 
               261 , 262 : Groove portion 
               263 : Push button 
               1 : Module frame 
               2 : Skin 
               3 : Shooting member 
           
         
       
    
     BEST MODE 
     The detailed description of the present invention is provided to completely explain the present invention to a person with ordinary skill in the art. Throughout the specification, unless explicitly described to the contrary, when one component “comprises (includes)” another component or “characterized by” having a certain structure and a certain shape, this means that other components, structures, and shapes may be included without being excluded. 
     The present invention may be variously modified and may have various exemplary embodiments, and specific exemplary embodiments will be described in detail in the detailed description. However, the description of the exemplary embodiments is not intended to limit the contents of the present invention, but it should be understood that the present invention is to cover all modifications, equivalents and alternatives falling within the spirit and technical scope of the present invention. 
       FIG. 1  is a view illustrating a configuration of a perforated plate microstructure module  100  according to an exemplary embodiment of the present invention. Referring to  FIG. 1 , the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention includes a perforated plate  110 , base parts  120 , microneedles  130 , and a pressing member  140 . 
     The perforated plate microstructure module  100  may be configured such that the pressing member  140  having one or more pillars  141  is disposed at a side of the perforated plate  110  at which no microneedle  130  is formed. 
     The pressing member  140  having one or more pillars  141  may be in contact with the perforated plate  110  including the base parts  120  or spaced apart from the perforated plate  110  at an interval of 1 cm or less. 
       FIG. 2  is a cross-sectional view of the perforated plate microstructure module  100 . Referring to  FIG. 2 , the perforated plate microstructure module  100  may be configured such that the perforated plate  110  and the pressing member  140  are coupled to a module frame  1 . All the components of the perforated plate microstructure module  100  may be integrated and used for a single use. 
     The perforated plate  110  functions to include a drug delivery medium with low coupling force so that the drug delivery medium is easily delivered to the user&#39;s skin. In order to perform this function, one or more openings  111 , which are spaced apart from one another at predetermined intervals, are formed in a central portion of the perforated plate  110 , and a part or the entirety of each of the openings  111  may be filled with the base part  120  to be described below. 
     The perforated plate  110  may have strength enough to prevent the perforated plate  110  from being deformed or broken by physical force when the physical force for inserting the microneedles  130  into the skin is applied. The perforated plate  110  is coupled to the base part  120  with low coupling force so that the microneedle  130  may be easily separated when the external physical force is applied. 
     The external physical force may be 0.01 to 100 N. When the physical force is lower than 0.01 N, the base part  120  cannot be easily separated from the perforated plate  110 . In contrast, when the physical force is higher than 100 N, the force applied to the skin by the microneedle  130  increases, which causes pain in the skin. The external physical force, which is applied to insert the microneedles  130  into the skin, may be adjusted by the number of openings  111  included in the perforated plate  110 . 
     The opening  112  may be convex inward or a coating layer is additionally provided between the base part  120  and the perforated plate  110  in order to compensate for the low coupling force and prevent the perforated plate  110  and the base part  120  from being separated from each other during storage and transport due to the low coupling force. 
     The perforated plate  110  and the base part  120  to be described below may be made of a hydrophilic material. For example, the hydrophilic material may include a hydrophilic polymer including, as a monomer, hyaluronic acid (HA), carboxymethyl cellulose (CMC), methacrylic acid (MA), 2-hydroxyethyl methacrylate (HEMA), ethyl acrylate (EA), 1-vinyl-2-pyrrolidinone (VP), propenoic acid 2-methyl ester (PAM), monomethacryloyloxyethyl phthalate (EMP), or ammonium sulphatoethyl methacrylate (SEM). 
     The base parts  120  may be formed in the one or more openings  111  formed in the perforated plate  110  and may function to support the microneedles  130  to be described below. In order to perform this function, the base part  120  may fill a part or the entirety of the opening  111  of the perforated plate  110 . 
     Specifically, the base part  120  may occupy 1% to 100% of a height of the perforated plate  110 . If the base part  120  occupies less than 1% of the height of the perforated plate  110 , the microneedle  130  and the base part  120  may be separated from the perforated plate  110  during a process of changing a shape after spotting a viscous composition on the base part  120 . 
     The base part  120  is configured to be inserted into the skin together with the microneedle  130  to be described below, and the base part  120  may be made of a biodegradable substance or may include a drug. Therefore, the base part  120  may contain the same composition as the microneedle  130  containing the drug, or the base part  120  and the microneedle  130  may have different compositions. 
     In addition, the coupling force between the base part  120  and the perforated plate  110  may be lower than physical force applied to shoot the microneedle  130 . The coupling force between the base part  120  and the perforated plate  110  may be adjusted depending on one or more of a material of the perforated plate  110 , a material of the base part  120 , a height of the base part  120 , and plasma surface treatment. 
     In this case, the material of the perforated plate  110  and the material of the base part  120  may vary depending on the type and concentration of the material constituting the perforated plate  110  and the base part  120 . 
     In order to adjust the coupling force between the base part  120  and the perforated plate  110 , the perforated plate  110  may be made of any one of plastic such as polycarbonate (PC), general purpose polystyrene (GPPS), and polymethyl methacrylate (PMMA), metal, and a ductile material such as rubber. 
     The surface treatment on the perforated plate  110  may include chemical treatment, ultraviolet irradiation, and plasma treatment. Specifically, the coupling force between the base part  120  and the perforated plate  110  may be adjusted in accordance with the type and concentration of chemical substances used for the chemical treatment, and intensity and time of emission of the ultraviolet rays and the plasma. 
     The microneedle  130  may be separated from the perforated plate  110  by the pressing member  140  to be described below to function to deliver the drug into the user&#39;s skin. In order to perform this function, the microneedle  130  may be provided on the base part  120  and made of a biocompatible or biodegradable substance including a drug. 
     The microneedle  130  may be formed by spotting a viscous composition containing a biocompatible or biodegradable substance on the base part  120 . In this case, the term “viscous composition” means a composition having an ability to form the microneedle by changing in shape. 
     The microneedle  130  may have a circular horizontal cross section. In this case, a portion of the microneedle  130 , which is to be joined to the base part  120 , may have a circular shape having a predetermined area. 
     In the present specification, the term “biocompatible substance” means a substance which is substantially not toxic to a human body, is chemically inactive, and is not immunogenic. In the present specification, the term “biodegradable substance” means a substance that may be degraded by a bodily fluid, a microorganism, or the like in a living body. 
     For example, the biocompatible or biodegradable substance, which may be used in the present invention, may be polyester, polyhydroxyalkanoate (PHAs), poly(α-hydroxyacid), poly(β-hydroxyacid), poly(3-hydroxybutyrate-co-valerate; PHBV), poly(3-hydroxyproprionate; PHP), poly(3-hydroxyhexanoate; PHH), poly(4-hydroxyacid), poly(4-hydroxybutyrate), poly(4-hydroxyvalerate), poly(4-hydroxyhexanoate), poly(ester amide), polycaprolactone, polylactide, polyglycolide, poly(lactide-co-glycolide; PLGA), polydioxanone, polyorthoester, polyetherester, polyanhydride, poly(glycolic acid-co-trimethylene carbonate), polyphosphoester, polyphosphoester urethane, poly(amino acid), polycyanoacrylate, poly(trimethylene carbonate), poly(imino carbonate), poly(tyrosine carbonate), polycarbonate, poly(tyrosine arylate), polyalkylene oxalate, polyphosphazene, PHA-PEG, ethylene vinyl alcohol copolymer (EVOH), polyurethane, silicone, polyester, polyolefin, polyisobutylene and ethylene-alphaolefin copolymer, styrene-isobutylene-styrene triblock copolymer, acrylic polymer and copolymer, vinyl halide polymer and copolymer, polyvinyl chloride, polyvinyl ether, polyvinyl methyl ether, polyvinylidene halide, polyvinylidene fluoride, polyvinylidene chloride, polyfluoro alkene, polyperfluoroalkene, polyacrylonitrile, polyvinyl ketone, polyvinyl aromatics, polystyrene, polyvinyl ester, polyvinyl acetate, ethylene-methyl methacrylate copolymer, acrylonitrile-styrene copolymer, ABS resin and ethylene-vinyl acetate copolymer, polyamide, alkyd resin, polyoxymethylene, polyimide, polyether, polyacrylate, polymethacrylate, polyacrylic acid-co-maleic acid, chitosan, dextran, cellulose, heparin, hyaluronic acid, alginate, inulin, starch, or glycogen, and particularly, may contain one or more substances selected from polyester, polyhydroxyalkanoate (PHAs), poly(α-hydroxyacid), poly(β-hydroxyacid), poly (3-hydroxybutyrate-co-valerate; PHBV), poly(3-hydroxyproprionate; PHP), poly(3-hydroxyhexanoate; PHH), poly(4-hydroxyacid), poly(4-hydroxybutyrate), poly(4-hydroxyvalerate), poly(4-hydroxyhexanoate), poly(ester amide), polycaprolactone, polylactide, polyglycolide, poly(lactide-co-glycolide; PLGA), polydioxanone, polyorthoester, polyether ester, polyanhydride, poly(glycolic acid-co-trimethylene carbonate), polyphosphoester, polyphosphoester urethane, poly(amino acid), polycyano acrylate, poly(trimethylene carbonate), poly(imino carbonate), poly(tyrosine carbonate), polycarbonate, poly(tyrosine arylate), polyalkylene oxalate, polyphosphazene, PHA-PEG, chitosan, dextran, cellulose, heparin, hyaluronic acid, alginate, inulin, starch, and glycogen. 
     In the present invention, the drug, which may be used for the microneedle  130 , is not particularly limited. For example, the drug includes a chemical drug, a protein drug, a peptide drug, nucleic acid molecules for gene therapy, nanoparticles, functional cosmetic effective ingredients, and cosmetic ingredients. 
     For example, the drug, which may be used in the present invention, includes, but not limited to, an anti-inflammatory drug, an analgesic, an anti-arthritis drug, an antispasmodic, an antidepressant, an antipsychotic drug, a tranquilizer, an anti-anxiety drug, a drug antagonist, an anti-parkinsonism drug, a cholinergic agonist, an anticancer drug, an antiangiogenic drug, an immunosuppressant, an antiviral drug, an antibiotic, an appetite suppressant, an analgesic, an anticholinergic, an antihistamine, an antimigraine drug, hormones, a coronary vasodilator, a cerebral vasodilator, a peripheral vasodilator, a contraceptive, an antithrombotic drug, a diuretic, an antihypertensive agent, a therapeutic agent for cardiovascular disease, and a cosmetic ingredient (e.g., an anti-wrinkle agent, a skin aging inhibitor, and a skin whitening agent). 
     While the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention has been described as including the plurality of microneedles  130 , the number of microneedles  130  is not particularly limited as long as the perforated plate microstructure module  100  may perform the above-mentioned functions. For example, the perforated plate microstructure module  100  according to the present invention may include the single microneedle  130  using a highly concentrated formulation. 
     The pressing member  140  may function to separate the base part  120  and the microneedle  130  from the perforated plate  110  by using the physical force applied from the outside. In order to perform this function, the pressing member  140  includes the one or more pillars  141  and may have strength enough to prevent the pressing member  140  from being deformed or damaged by the physical force when the physical force is applied. 
       FIG. 3  is a cross-sectional view illustrating a state in which the microneedles  130  are inserted into the skin by the pressing member  140  according to the exemplary embodiment of the present invention. 
     Referring to  FIG. 3 , the one or more pillars  141  are provided on the pressing member  140  so as to correspond to the positions of the openings  111  of the perforated plate  110 , such that the pressing member  140  may separate the base part  120  from the perforated plate  110  by using the force applied from the outside. 
     Specifically, the physical force applied to the pillar  141  may push downward the base part  120 , which is formed in the opening  111 , from the perforated plate  110  to insert the base part  120  into the skin  2  by a predetermined depth. Because the physical force applied to the pillar  141  is higher than the coupling force between the base part  120  and the perforated plate  110 , the base part  120  may be easily separated from the perforated plate  110  by the pressing force of the pillar  11 . 
       FIG. 4  is a cross-sectional view illustrating a state in which the perforated plate microstructure module  100  is returned back to an original state after the microneedle  130  is inserted into the skin. 
     Referring to  FIG. 4 , it can be seen that when the base part  120  is separated from the perforated plate  110  by the pressing member  140 , the base part  120  is inserted into the skin  2  in a state in which the base part  120  is coupled to the microneedle  130  without being separated from the microneedle  130 , and only the vacant opening  111  exists in the perforated plate  110 . 
     Meanwhile, the exemplary embodiment of the present invention provides a shooting member  3  for providing the force applied from the outside, but it should be noted that a method of applying the physical force is not limited to a particular method and may be configured as methods using hydraulic pressure, pneumatic pressure, and an elastic body. 
     Hereinafter, a shooting microstructure module and an applicator according to another exemplary embodiment of the present invention will be described in detail with reference to the drawings.  FIG. 5  is a perspective view illustrating a state in which the shooting microstructure module according to another exemplary embodiment of the present invention is mounted on the applicator, and  FIG. 6  is a cross-sectional view illustrating the shooting microstructure module side illustrated in  FIG. 5 . 
     Referring to  FIG. 5 , a shooting microstructure module  200  is detachably mounted on an applicator  20  according to another exemplary embodiment of the present invention. In this case, the shooting microstructure module  200  may function as a head of the applicator  20 . 
     According to the present invention, a perforated layer, which is to be in contact with the skin, and a pillar, which is to be inserted into the skin, may be separately configured in the shooting microstructure module  200  and configured to be attachable to and detachable from the applicator  20 , such that the pillar and the perforated layer may be easily replaced after single use, thereby preventing a risk of secondary infection during the process of implanting the microstructure. 
     The applicator  20  serves to implant the microstructure mounted on the shooting microstructure module  200  into the skin and includes a main body housing  21  and shooting members  12  and  13 . 
     The main body housing  21  has a cylindrical shape, but the present invention is not particularly limited to the shape of the main body housing  21 . A through port (not illustrated) for a pushing member  22  is positioned at an upper side of the main body housing  21 , and the shooting microstructure module  200  is mounted at a lower side of the main body housing  21 . 
     The shooting members  12  and  13  are provided in the main body housing  21  to press the pressing member or the microstructure of the shooting microstructure module  200 , and the shooting members  12  and  13  include a pushing member  22  and a piston  23 . 
     The pushing member  22  protrudes outward through the through port (not illustrated) provided at one side of the main body housing  21 . The pushing member  22  is manipulated by a user to shoot the piston  23  toward a pressing member  240  of the shooting microstructure module  200 . In this case, the term “shooting” means that the microneedle  234  moves forward and is separated from the shooting microstructure module  200 . 
     Referring to  FIG. 6 , the piston  23  may press the pressing member  240  of the shooting microstructure module  200  by the manipulation of the pushing member  22 . In this case, for simplification of the drawings, an elastic member received in the main body housing  21  and configured to provide pressing force to the piston  23  is omitted and constituent elements associated with the elastic member are omitted. 
     The example in which the pushing member  22  and the piston  23  are provided as the shooting members has been described, but the present invention is not particularly limited thereto. That is, the shooting member is not particularly limited as long as the shooting member presses pillars  244  of the shooting microstructure module  200 . 
     Because the microneedle  234  may be implanted in the skin  2  by the applicator  20  without an adhesive sheet, the microneedle  234  may be used for a curved or frequently moving joint area, thereby minimizing the restriction of the implantation site, like a micro-patch. 
     The shooting microstructure module  200  includes a housing  210 , a perforated layer  220 , a shooting microstructure  230 , and the pressing member  240 . 
     An upper side of the housing  210  is attachable to and detachable from the applicator  20 , and the housing  210  has a hollow portion. The housing  210  may have a cylindrical shape, but the present invention is not particularly limited thereto. The housing  210  has a coupling member to be coupled to the applicator  20 , and the coupling member will be described below with reference to  FIGS. 12 to 14 . 
     The perforated layer  220  is provided at a lower side of the housing  210  and has one or more openings  222 . In this case, the perforated layer  220  may be formed integrally with the housing  210 . In this case, the housing  210  may define a sidewall of the perforated layer  220 . 
       FIG. 7  is a perspective view illustrating the housing and the perforated layer illustrated in  FIG. 6 . 
     The perforated layer  220  may have support parts  224  for supporting the pressing member  240 . In this case, the support parts  224  may be formed at the periphery of the one or more openings  222  so as not to constrain the shooting operation of the pillar  244 . 
     As illustrated in  FIG. 6 , catching parts  246  provided on the pressing member  240  may be seated on the support parts  224 . As a result, the support parts  224  may support the pressing member  240  so that the pillar  244  is disposed at a predetermined height from the perforated layer  220 . 
     The shooting microstructure  230  includes base parts  232  and microneedles  234 . In this case, the shooting microstructure  230  is disposed in the housing  210  and mounted on an upper portion of the perforated layer  220 . 
     The base part  232  has a plate shape, and the one or more microneedles  234  are provided on surfaces of the base parts  232 . In this case, the one or more microneedles  234  are provided on the surfaces of the base parts  232  and disposed at positions corresponding to the openings  222  of the perforated layer  220 . 
     In the present invention, the drug, which may be used for the microneedle  234 , is not particularly limited. For example, the drug includes a chemical drug, a protein drug, a peptide drug, nucleic acid molecules for gene therapy, nanoparticles, functional cosmetic effective ingredients, and cosmetic ingredients. 
     For example, the drug, which may be used in the present invention, includes, but not limited to, an anti-inflammatory drug, an analgesic, an anti-arthritis drug, an antispasmodic, an antidepressant, an antipsychotic drug, a tranquilizer, an anti-anxiety drug, a drug antagonist, an anti-parkinsonism drug, a cholinergic agonist, an anticancer drug, an antiangiogenic drug, an immunosuppressant, an antiviral drug, an antibiotic, an appetite suppressant, an analgesic, an anticholinergic, an antihistamine, an antimigraine drug, hormones, a coronary vasodilator, a cerebral vasodilator, a peripheral vasodilator, a contraceptive, an antithrombotic drug, a diuretic, an antihypertensive agent, a therapeutic agent for cardiovascular disease, and a cosmetic ingredient (e.g., an anti-wrinkle agent, a skin aging inhibitor, and a skin whitening agent). 
     In addition, in the present invention, the material of the microneedle  234  contains a biocompatible or biodegradable substance. In the present specification, the term “biocompatible substance” means a substance which is substantially not toxic to a human body, is chemically inactive, and is not immunogenic. In the present specification, the term “biodegradable substance” means a substance that may be degraded by a bodily fluid, a microorganism, or the like in a living body. 
     In this case, the microneedle  234  may be formed by spotting viscous compositions of drugs. In this case, the term “viscous composition” means a composition having an ability to form the microstructure by changing in shape. 
     The microneedle  234  has a circular horizontal cross section. In this case, a portion of the microneedle  234 , which is to be joined to the base part  232 , has a circular shape having a predetermined area. The microneedle  234  may include a pointed end portion at a portion of the microneedle  234  which is to be implanted in the skin  2 . 
     In this case, the microneedle  234  may be disposed in the housing  210  so that the end portion of the microneedle  234  does not protrude outward from the opening  222  in order to protect the end portion thereof. For example, a height of the microneedle  234 , from the base part  232  to the end portion, may be smaller than a depth of the opening  222 . 
     The pressing member  240  includes a plate  242 , the pillars  244 , and the catching parts  246 .  FIG. 8  is a perspective view illustrating the pressing member illustrated in  FIG. 6 . 
     The plate  242  may have a plate shape corresponding to a cross-sectional shape of the housing  210  so that the plate  242  may be received in the housing  210 .  FIG. 8  illustrates that the plate  242  has a circular shape, but the present invention is not particularly limited thereto. 
     The pillars  244  may be provided on one surface of the plate  242 . For example, the one or more pillars  244  may be provided on a lower surface of the plate  242  and disposed at the positions corresponding to the microneedles  234  and the openings  222 . In this case, the pillars  244  may have the same length. 
     The lengths of the pillars  244  may vary depending on the positions on the plate  242  at which the pillars  244  are provided. For example, the pillars  244 , which are provided at an outer peripheral portion and a central portion of the plate  242 , may have different lengths. In this case, the pillar provided at the outer peripheral portion of the plate may have a longer length than the pillar provided at the central portion of the plate. 
     As a result, in a case in which a distance between the plate  242  and the skin  2  varies depending on the shape of the curved skin  2 , the microneedles  234  may be uniformly inserted into the curved skin  2  when the microneedles  234  are inserted into the curved skin  2  because the lengths of the pillars  244  vary depending on the shape of the curved skin  2 . 
     In addition, the pillar  244  may have a length larger than a thickness of the opening  222  of the perforated layer  220 . That is, the pillar  244  may protrude outward from the opening  222  in order to implant the microneedle  234  into the skin  2 . In this case, the pillar  244 , together with the microneedle  234 , may be inserted into the skin  2 . 
     The catching parts  246  may be provided at the positions corresponding to the support parts  224  of the perforated layer  220 . In this case, the catching part  246  may be positioned at one end of the support part  224 . As a result, the plate  242  may be disposed at a predetermined height from the perforated layer  220 . 
     The catching part  246  may be formed to be broken by the shooting operations of the piston  23  and the pillar  244 . That is, the catching part  246  may be broken by the pressing force applied to the plate  242 . 
     For example, the catching part  246  may have a shape and a size corresponding to a cross section of the pillar  244 . In this case, the catching part  246  may be thinner than a thickness of the plate  242  so that the catching part  246  may be easily broken by the pressing force applied to the plate  242 . 
     As another example, the plate  242  may have a through port  248  corresponding to a cross section of the pillar  244 , and the catching part  246  may be provided in at least a part of the through port  248 . In this case, the catching part  246  may be thinner than a thickness of the plate  242  so that the catching part  246  may be easily broken by the pressing force applied to the plate  242 . 
     As illustrated in  FIG. 6 , in the state in which the shooting microstructure module  200  is mounted on the applicator  20 , the shooting microstructure module  200  brings the microneedles  234  into close contact with the skin  2  in order to implant the microneedles  234  into the skin  2 . 
     In this case, as the support parts  224  of the perforated layer  220  are caught by the catching parts  246  of the plate  242 , the pressing member  240  may be disposed at the predetermined height from the perforated layer  220 . In this case, the shooting microstructure  230  may remain mounted on the upper portion of the perforated layer  220 . 
     Hereinafter, the operation of the applicator  20  implanting the microneedles  234  into the skin  2  will be described in detail with reference to  FIGS. 9 to 11 . 
       FIG. 9  is a cross-sectional view illustrating a state in which the applicator illustrated in  FIG. 6  performs shooting,  FIG. 10  is a cross-sectional view illustrating a state in which the microstructure illustrated in  FIG. 9  is separated, and  FIG. 11  is a cross-sectional view illustrating a state in which the shooting microstructure module illustrated in  FIG. 10  is separated from the applicator. 
     Referring to  FIG. 6 , when the user shoots the applicator  20  by using the pushing member  22 , the piston  23  presses the plate  242 . In this case, when the plate  242  is moved to the perforated layer  220  by the pressing force applied to the plate  242  by the piston  23 , the catching part  246  is broken by the support part  224 . 
     Referring to  FIG. 9 , as the catching part  246  is broken, the through port  248  of the plate  242  is guided to the support part  224 . In this case, the constraint of the plate  242  by the restrictive force of the support part  224  is released, such that the plate  242  is shot to the perforated layer  220 . 
     When the plate  242  is pressed to the perforated layer  220 , the pillars  244  protrude outward through the openings  222  of the perforated layer  220 . In this case, the pillars  244  penetrate an underlying layer of the shooting microstructure  230 , such that the microneedles  234  may be separated from the base parts  232  and implanted into the skin  2 . 
     Since the microneedles  234  are completely implanted into the skin  2 , it is possible to improve the efficacy of delivering the drug through the microneedles  234 . Since the accurate amount of drug contained in the microneedle  234  may be delivered, it is possible to improve stability and uniformity in using the drug. 
     Referring to  FIG. 10 , the applicator  20  is separated from the skin  2  in the state in which the microneedle  234  is implanted into the skin  2 . In this case, in the state in which the microneedle  234  is implanted into the skin  2 , the pillar  244  may be separated from the skin  2 . 
     In this case, because the perforated layer  220  is in contact with the skin  2  and the pillar  244  is inserted into the skin  2 , there is a high risk of secondary contamination in case of reuse. The shooting microstructure module  200  is replaced and discarded after single use, which prevents secondary contamination. 
     Referring to  FIG. 11 , in the state in which the piston  23  is retracted rearward by the pushing member  22  of the applicator  20 , the shooting microstructure module  200  is separated from the applicator  20 . 
     As described above, the shooting microstructure module  200  separated from the applicator  20  may be discarded. That is, since the perforated layer  220 , which has been in contact with the skin  2 , and the pillar  244 , which has been inserted into the skin  2 , are discarded, it is possible to prevent secondary contamination caused by reuse. 
     As illustrated in  FIG. 6 , a new shooting microstructure module  200  may be mounted on a lower side of the applicator  20 . 
     Meanwhile, the shooting microstructure module  200  according to another exemplary embodiment of the present invention may further include a coupling member  251 ,  252 , or  253  provided to couple the housing  210  to the applicator  20 . 
     The coupling member  251 ,  252 , or  253  may be configured by any one of rotation coupling, hook coupling, insertion coupling, catching coupling, magnetic coupling, and Velcro. In this case, the coupling method is not particularly limited to the above-mentioned coupling methods, and the shooting microstructure module  200  and the applicator  20  may be coupled in various ways. In this case, a coupling member, which corresponds to the coupling member  251 ,  252 , or  253  formed on the housing  210 , may be formed on the main body housing  21 . 
     Since the coupling members facilitates the replacement of the perforated layer  220 , which has been in contact with the skin  2 , and the pillar  244 , which has been inserted into the skin  2 , it is possible to improve convenience of use and prevent a risk of secondary contamination caused by reuse. 
       FIG. 12  is a cross-sectional view illustrating an example in which the shooting microstructure module according to the exemplary embodiment of the present invention is coupled to the applicator. In this case, for simplification of the drawings, the main body housing  21  of the applicator  20  and the housing  210  of the shooting microstructure module  200  are schematically illustrated. 
     Referring to  FIG. 12 , the shooting microstructure module  200  and the applicator  20  may be coupled by rotation coupling. In this case, a screw thread  24  may be formed along an outer circumference at one side of the main body housing  21 , and the coupling member  251  may include a screw thread  24  formed along an inner circumference at one side of the housing  210 . 
     Similarly, a screw thread  24  may be formed along an inner circumference at one side of the main body housing  21 , and the coupling member  251  may include a screw thread  24  formed along an outer circumference at one side of the housing  210 . 
     In this case, when the housing  210  is rotated in one direction below the main body housing  21 , the screw thread  24  of the housing  210  is rotated along the screw thread  24  of the main body housing  21 , and the housing  210  is moved to the main body housing  21 , such that the housing  210  may be coupled to the main body housing  21 , and as a result, the shooting microstructure module  200  may be coupled to the applicator  20 . 
     On the contrary, when the housing  210  is rotated in a reverse direction in the state in which the shooting microstructure module  200  is coupled to the applicator  20 , the screw thread of the housing  210  is rotated along the screw thread  24  of the main body housing  21 , and the housing  210  is moved outward from the main body housing  21 , such that the housing  210  may be separated from the main body housing  21 , and as a result, the shooting microstructure module  200  may be separated from the applicator  20 . 
       FIG. 13  is a cross-sectional view illustrating another example in which the shooting microstructure module according to the exemplary embodiment of the present invention is coupled to the applicator. 
     Referring to  FIG. 13 , the shooting microstructure module  200  and the applicator  20  may be coupled by catching coupling. In this case, a groove portion  261  is formed on an outer circumferential surface at one side of the main body housing  21 , and the coupling member may include a protrusion portion  252  formed at one end of the housing  210  so as to correspond to the groove portion  261 . The protrusion portion  252  may have elasticity so that protrusion portion  252  may be spread to the outside of the main body housing  21 . 
     In this case, the housing  210  is mounted on the main body housing  21  in the state in which the protrusion portion  252  is spread to the outside of the main body housing  21 . In this case, as the protrusion portion  252  of the housing  210  is inserted and fixed into the groove portion  261  of the main body housing  21 , the housing  210  may be coupled to the main body housing  21 , and thus the shooting microstructure module  200  may be coupled to the applicator  20 . 
     On the contrary, as the housing  210  is moved in a reverse direction to the main body housing  21  in the state in which the shooting microstructure module  200  is coupled to the applicator  20  and the protrusion portion  252  is spread to the outside of the main body housing  21 , the housing  210  may be separated from the main body housing  21 , and thus the shooting microstructure module  200  may be separated from the applicator  20 . 
     Meanwhile, as a combination of the rotation coupling and the catching coupling, the groove portion  261  may have a “¬” shape. In this case, the groove portion  261  may include an extension portion vertically extending to one end of the main body housing  21 . The protrusion portion  252  does not have elasticity. 
     In this case, when the housing  210  is rotated to one side of the main body housing  21  in the state in which the protrusion portion  252  is vertically inserted through the extension portion of the groove portion  261 , the protrusion portion  252  may be rotated in a horizontal direction along the groove portion  261 . As a result, the housing  210  may be coupled to the main body housing  21 , and thus the shooting microstructure module  200  may be coupled to the applicator  20 . 
     On the contrary, in the state in which the shooting microstructure module  200  is coupled to the applicator  20 , the protrusion portion  252  is rotated in a reverse horizontal direction along the groove portion  261 , and then the housing  210  is moved downward from the main body housing  21 , such that the housing  210  may be separated from the main body housing  21 , and thus the shooting microstructure module  200  may be separated from the applicator  20 . 
       FIG. 14  is a cross-sectional view illustrating still another example in which the shooting microstructure module according to the exemplary embodiment of the present invention is coupled to the applicator. 
     Referring to  FIG. 14 , the shooting microstructure module  200  and the applicator  20  may be coupled by insertion coupling. In this case, a groove portion  262 , which is opened downward, may be formed at an end at one side of the main body housing  21 . In this case, a push button  263  may be provided to communicate with the groove portion  262 . The coupling member may include a hook member  253  provided at one end of the housing  210 . In this case, the hook member  253  may have elasticity so as to be bent to one side. 
     In this case, when the hook member  253  of the housing  210  is inserted into the groove portion  262  of the main body housing  21 , the hook member  253  is inserted and fixed into the groove portion  262 , such that the housing  210  may be coupled to the main body housing  21 , and thus the shooting microstructure module  200  may be coupled to the applicator  20 . 
     On the contrary, when the push button  263  is pushed in the state in which the shooting microstructure module  200  is coupled to the applicator  20 , the push button  263  is inserted into the groove portion  262  and pushes the hook member  253 , such that the hook member  253  is bent to one side, and thus the hook member  253  may be separated from the groove portion  262 . In this state, as the housing  210  is moved downward from the main body housing  21 , the housing  210  may be separated from the main body housing  21 , and thus the shooting microstructure module  200  may be separated from the applicator  20 . 
     Meanwhile, instead of the groove portion  262  of the main body housing  21 , a second hook member, which corresponds to the hook member  253 , may be provided in the main body housing  21 . In this case, the hook member  253  may have a push button provided at one side thereof. As another example, the second hook member may have a push button at one side thereof, and the push button may protrude outward from the main body housing  21 . 
     In this case, when the housing  210  is pressed from below the main body housing  21 , the hook member  350  is coupled to the second hook member in the main body housing  21 , such that the housing  210  may be coupled to the main body housing  21 , and thus the shooting microstructure module  200  may be coupled to the applicator  20 . 
     On the contrary, when the push button provided on the hook member  253  or the push button provided on the second hook member is pushed in the state in which the shooting microstructure module  200  is coupled to the applicator  20 , the corresponding push button presses and bends the hook member  253  or the second hook member to one side, such that the hook member  253  and the second hook member may be separated from each other. In this state, as the housing  210  is downward from the main body housing  21 , the housing  210  may be separated from the main body housing  21 , and thus the shooting microstructure module  200  may be separated from the applicator  20 . 
     Comparative Example 
     Comparative Example shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  which is not subjected to the plasma surface treatment. 
     Experimental Example 1 
     Experimental Example 1 shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  on which the plasma surface treatment has performed for 1 minute. 
     Experimental Example 2 
     Experimental Example 2 shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  on which the plasma surface treatment has performed for 2 minutes. 
     Experimental Example 3 
     Experimental Example 3 shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  on which the plasma surface treatment has performed for 3 minutes. 
     Experimental Example 4 
     Experimental Example 4 shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  on which the plasma surface treatment has performed for 4 minutes. 
     Experimental Example 5 
     Experimental Example 5 shows an experimental result of measuring the coupling force between the perforated plate  110  and the base part  120  of the perforated plate microstructure module  100  according to the exemplary embodiment of the present invention by using the perforated plate  110  on which the plasma surface treatment has performed for 5 minutes. 
     In order to compare changes in coupling force between the perforated plate  110  and the base part  120  over plasma surface treatment time, Experimental Examples all have the same configuration in which the  69  openings  111  are formed in the perforated plate  110 , and the experiments were performed under the condition in which the height of the base part  120  and the material of the perforated plate  110  remain the same. 
     The experiments measured the coupling force between the perforated plate  110  and the base part  120  by slowly applying external force to the perforated plate microstructure module  100  and measuring a peak value at the moment when the perforated plate  110  and the base part  120  are separated from each other. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Comparative 
                 Experimental 
                 Experimental 
                 Experimental 
                 Experimental 
                 Experimental 
               
               
                 Examples 
                 Example 
                 Example 1 
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Plasma 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
               
               
                 Surface 
               
               
                 Treatment 
               
               
                 Time 
               
               
                 (min) 
               
               
                 Coupling 
                 12.49 
                 21.37 
                 46.11 
                 45.5 
                 47.3 
                 46.04 
               
               
                 Force 
               
               
                 (N) 
               
               
                   
               
            
           
         
       
     
     Table 1 and  FIG. 15  are a table and a graph illustrating experimental results of measuring the coupling force between the perforated plate  110  and the base part  120  in a Comparative Example and Experimental Examples 1 to 5. Referring to Table 1 and  FIG. 15 , it can be seen that in the Comparative Example, the perforated plate  110  and the base part  120  were separated from each other when comparatively low force (12.49 N) was applied in comparison with Experimental Examples 1 to 5. 
     It can be seen that in Experimental Examples 2 to 5, the perforated plate  110  and the base part  120  were separated from each other when comparatively high force (45.5 N to 46.04 N) was applied in comparison with Experimental Example 1 in which the coupling force was 21.37 N. 
     Consequently, it can be seen that the coupling force between the perforated plate  110  and the base part  120  may be increased through the plasma surface treatment on the perforated plate  110 . However, it can be seen that the coupling force between the perforated plate  110  and the base part  120  may be further increased when the plasma surface treatment on the perforated plate  110  continues for 1 minute or more, and the change in coupling force between the perforated plate  110  and the base part  120  is insignificant when the plasma surface treatment continues for 2 minutes or more. 
     &lt;Coupling Force Experimental Data&gt; 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Experiment 1 (N) 
                 Experiment 2 (N) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Example 1 
                 0.8182 
                 Example 5 
                 0.7680 
               
               
                   
                 Example 2 
                 0.8929 
                 Example 6 
                 0.7032 
               
               
                   
                 Example 3 
                 0.8709 
                 Example 7 
                 0.8841 
               
               
                   
                 Example 4 
                 1.0125 
                 Example 8 
                 1.3101 
               
               
                   
                 Average (A) 
                 0.8986 
                 Average (B) 
                 0.9163 
               
               
                   
                 (Example 1~4) 
                   
                 (Example 5~8) 
                   
               
            
           
           
               
               
            
               
                   
                 coupling force(B-A) 0.0177 N 
               
               
                   
                   
               
            
           
         
       
     
     &lt;Experiment 1&gt; 
     Experiment 1 shows an experimental result of measuring the pressing force. wherein the pressing force is the measured value when the pillar of the pressing member is inserted into the openings of the perforated plate. 
     &lt;Experiment 2&gt; 
     Experiment 2 shows an experimental result of measuring the pressing force. wherein the pressing force is the measured value when the pillar of the pressing member is inserted into the base part filling in the opening of the perforated plate. 
     In order to measure critical value of the coupling force between the perforated plate and the base parts, pressing force was measured when the pillar of the pressing member is inserted into the openings of the perforated plate. 
     The coupling force is calculated by the difference between the base part filling in the opening and the base parts being empty. 
     Table 2 is a table illustrating experiment results of measuring the pressing force when the pillar of the pressing member is inserted into the openings of the perforated plate. 
     Referring to Table 2, it can be seen that the base part and the perforated plate coupled are separable by force of at least 0.0177 N. 
     While the present invention has been described above with reference to the exemplary embodiments, it may be understood by those skilled in the art that the present invention may be variously modified and changed without departing from the spirit and scope of the present invention disclosed in the claims.