# US 11,433,225 B2 · Microneedle structure and biodegradable microneedle thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,433,225 B2 - Document ID: US11433225B2 - Status: Granted - Kind: B2 - Application number: 16/862,699 - Filed: 2020-04-30 - Published: 2020-11-19 - Granted: 2022-09-06 - Earliest claimed: 2019-05-15 - Assignees: Microbase Technology Corp. - Applicants: Microbase Technology Corp. - Inventors: Shu-Pin Hsieh; Ting-Kai Tsai - Web page: https://patentgrep.com/patent/US11433225B2 ## CPC - A61M 37/0015: {by using microneedles} - A61M 2037/0046: {Solid microneedles} - 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)} ## Abstract A microneedle structure and a biodegradable microneedle thereof are provided. The biodegradable microneedle defining a central axis includes a first step portion and a second step portion that is taperedly extending from the first step portion along the central axis. The biodegradable microneedle has a total height along the central axis and a maximum internal diameter along a direction perpendicular to the central axis. The total height is within a range of 380-430 μm, and an aspect ratio defined by the total height divided by the maximum internal diameter is within a range of 1.2-2.2. In a cross section of the biodegradable microneedle having the central axis, a part of the second step portion arranged away from the first step portion having a corner. The corner has an angle within a range of 65-100 degrees and faces toward the first step portion. ## Claims ### Claim 1 A microneedle structure, comprising: a base; and a plurality of biodegradable microneedles disposed on the base and each defining a central axis, wherein each of the biodegradable microneedles has a total height along the central axis and a maximum internal diameter along a direction perpendicular to the central axis, and wherein the total height is within a range of 380-430 μm, and an aspect ratio defined by the total height divided by the maximum internal diameter is within a range of 1.2-2.2, wherein each of the biodegradable microneedles includes a first step portion connected to the base and a second step portion taperedly extending from the first step portion along a direction away from the base, wherein in a cross section of each of the biodegradable microneedles having the central axis, the second step portion has a contacting end for forming a microneedle tip, the contacting end is arranged away from the first step portion and has an angle within a range of 65-100 degrees, and the contacting end has an arced surface having a diameter within a range of 10-25 μm. ### Claim 2 (depends on 1) The microneedle structure according to claim 1, wherein in each of the biodegradable microneedles, the first step portion is tapered along a direction away from the base, and a top surface of the first step portion is entirely overlapped with a bottom surface of the second step portion. ### Claim 3 (depends on 1) The microneedle structure according to claim 1, wherein the base is biodegradable, and the base and the biodegradable microneedles are integrally formed as a one piece structure. ### Claim 4 (depends on 1) The microneedle structure according to claim 1, wherein the total height of each of the biodegradable microneedles is within a range of 380-400 μm. ### Claim 5 (depends on 1) The microneedle structure according to claim 1, wherein in each of the biodegradable microneedles, the first step portion is a pyramidal frustum, the second step portion is a pyramid, a bottom surface of the first step portion is connected to the base, and a top surface of the first step portion is entirely overlapped with a bottom surface of the second step portion. ### Claim 6 (depends on 5) The microneedle structure according to claim 5, wherein a ratio defined by a height of the first step portion in the total height divided by a height of the second step portion in the total height is within a range of 6.2-7.0. ### Claim 7 (depends on 1) The microneedle structure according to claim 1, wherein in each of the biodegradable microneedles, the first step portion is a conical frustum, the second step portion is a cone, a bottom surface of the first step portion is connected to the base, and a top surface of the first step portion is entirely overlapped with a bottom surface of the second step portion. ### Claim 8 (depends on 7) The microneedle structure according to claim 7, wherein a ratio defined by a height of the first step portion in the total height divided by a height of the second step portion in the total height is within a range of 1.8-2.6. ### Claim 9 A biodegradable microneedle of a microneedle structure defining a central axis, comprising: a first step portion; and a second step portion taperedly extending from the first step portion along the central axis, wherein the biodegradable microneedle has a total height along the central axis and a maximum internal diameter along a direction perpendicular to the central axis, wherein the total height is within a range of 380-430 μm, and an aspect ratio defined by the total height divided by the maximum internal diameter is within a range of 1.2-2.2, wherein in a cross section of the biodegradable microneedle having the central axis, the second step portion has a contacting end for forming a microneedle tip, the contacting end is arranged away from the first step portion and has an angle within a range of 65-100 degrees, and the contacting end has an arced surface having a diameter within a range of 10-25 μm. ### Claim 10 A biodegradable microneedle of a microneedle structure defining a central axis, comprising: a first step portion; and a second step portion taperedly extending from the first step portion along the central axis, wherein the biodegradable microneedle has a total height along the central axis and a maximum internal diameter along a direction perpendicular to the central axis, wherein the total height is within a range of 350-430 μm, and an aspect ratio defined by the total height divided by the maximum internal diameter is within a range of 1.2-5.0, wherein in a cross section of the biodegradable microneedle having the central axis, the second step portion has a contacting end for forming a microneedle tip, the contacting end is arranged away from the first step portion and has an angle within a range of 65-100 degrees.