# US 10,245,423 B2 · Method for manufacturing microstructure using centrifugal force and microstructure manufactured by same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,245,423 B2 - Document ID: US10245423B2 - Status: Granted - Kind: B2 - Application number: 14/889,808 - Filed: 2014-05-02 - Published: 2016-03-10 - Granted: 2019-04-02 - Earliest claimed: 2013-05-06 - Assignees: Juvic Inc. - Applicants: Juvic Inc. - Inventors: Hyung Il Jung; Hui Suk Yang; Su Yong Kim - Web page: https://patentgrep.com/patent/US10245423B2 ## CPC - A61M 37/0015: {by using microneedles} - B29C 41/085: {by rotating the former around its axis of symmetry} - C09D 101/08: Cellulose derivatives - A61K 9/5089: {Processes} - A61M 2037/0046: {Solid microneedles} - A61M 2037/0053: {Methods for producing microneedles} - B29K 2995/0056: Biocompatible, e.g. biopolymers or bioelastomers - B29L 2031/7544: {Injection needles, syringes} - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract The present invention relates to a method for manufacturing a microstructure, the method comprising the steps of: (a) preparing a viscous composition on a lower substrate; and (b) applying centrifugal force to the viscous composition to induce extension of the viscous composition, thereby manufacturing a microstructure. According to the present invention, (i) a microstructure having a micro-unit diameter and sufficient effective length and hardness is provided; (ii) any process that may destroy activation of a drug or cosmetic component, such as high-temperature treatment, organic solvent treatment, etc., is avoided; (iii) loss resulting from contact and separation is reduced; (iv) the limitation of aspect ratio of the manufactured microstructure is overcome; (v) the limitation of yield resulting from flatness is overcome; and (vi) microstructures of various shapes can be manufactured. ## Claims ### Claim 1 A method for manufacturing a microstructure, the method comprising: applying a viscous material onto a surface of a substrate; and rotating the substrate about an axis such that the surface faces away from the axis while rotating, which causes the viscous material to extend generally in a direction perpendicular to the surface and away from the axis by centrifugal force applied to the viscous material, thereby providing a microstructure comprising at least one microneedle elongated from and attached to the surface, wherein the method adjusts at least one dimension of the microstructure which is selected from the group consisting of a length, a diameter, and an aspect ratio by adjusting the centrifugal force. ### Claim 2 (depends on 1) The method according to claim 1, wherein the viscous material comprises at least one selected from the group consisting of a biocompatible substance, a biodegradable substance and a drug. ### Claim 3 (depends on 1) The method according to claim 1, wherein applying the viscous material comprises forming at least one drop of the viscous material on the surface. ### Claim 4 (depends on 1) The method according to claim 1, wherein the surface is curved or embossed to provide hills and valleys. ### Claim 5 (depends on 4) The method according to claim 4, wherein the at least one microneedle comprises a plurality of microneedles, wherein the viscous material is applied onto the surface such that the viscous material forms a layer that generally follows contour of the hills and valleys of the surface, wherein rotating the substrate causes the viscous material to extend from areas over the hills of the surface such that at least part of the resulting microneedles are elongated from and attached to the hills of the surface. ### Claim 6 (depends on 1) The method according to claim 1, wherein the substrate is substantially flat. ### Claim 7 (depends on 1) The method according to claim 1, further comprising: providing a device comprising a body and a plurality of through-holes that are extending from a first surface of the body to a second surface of the body; and after applying the viscous material and before rotating the substrate, placing the device on the viscous material such that the viscous material contacts the first surface; wherein rotating the substrate causes the viscous material extend into at least part of the plurality of through-holes. ### Claim 8 (depends on 1) The method according to claim 1, wherein the substrate is referred to as a first substrate, wherein the surface of the first substrate is referred to as a first surface wherein the method further comprises: arranging a second substrate with a second surface such that the second surface opposes and faces the first surface when rotating the first substrate, wherein rotating the first substrate causes the viscous material to extend such that one end of the viscous material contacts and is attached to the second surface while the other end of the viscous material is attached to the first surface. ### Claim 9 (depends on 8) The method according to claim 8, wherein the viscous material is a hydrophilic substance, the first surface is hydrophobic and the second surface is hydrophilic, wherein the method further comprising: moving the second substrate away from the first substrate in the direction, which causes the viscous material is detached from the first surface while the viscous material is attached to the second surface. ### Claim 10 (depends on 8) The method according to claim 8, further comprising moving the second substrate relative to the first substrate in the direction or in another direction perpendicular to the direction, which causes the viscous material to be separated at an intermediate point between the two ends of the viscous material to provide another microstructure. ### Claim 11 (depends on 1) The method according to claim 1, further comprising: depositing a first metal layer over the microstructure to provide a metal-deposited microstructure; plating a second metal layer onto the first metal layer of the metal-deposited microstructure to provide a metal-plated microstructure; and removing hardened viscous material from the metal-plated microstructure to obtain a micro-mold comprising the first metal layer and the second metal layer. ### Claim 12 A method for manufacturing a microstructure, the method comprising: providing a hollow structure comprising an inner space and an outlet, the hollow structure containing a viscous material within the inner space; and rotating the hollow structure about an axis, which causes at least a portion of the viscous material to move out through the outlet and extend away from the outlet by centrifugal force applied to the viscous material, thereby providing a microstructure comprising a microneedle elongated from and attached to the hollow structure, wherein the method adjusts at least one dimension of the microstructure which is selected from the group consisting of a length, a diameter, and an aspect ratio by adjusting the centrifugal force. ### Claim 13 (depends on 12) The method of claim 12, wherein the hollow structure comprises a piston and further contains another material, wherein the method further comprises: moving the piston to inject the other material into the microstructure while the centrifugal force is applied or after the centrifugal force is applied, wherein the other material comprises a drug, gas or fluid.