Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes  

作　　者：Hyeonhee Roh Young Jun Yoon Jin Soo Park Dong-Hyun Kang Seung Min Kwak Byung Chul Lee Maesoon Im 

机构地区：[1]Brain Science Institute,Korea Institute of Science and Technology(KIST),Seoul 02792,South Korea [2]Division of Electrical Engineering,College of Engineering,Korea University,Seoul 02841,South Korea [3]Micro/Nano Fabrication Center,KIST,Seoul 02792,South Korea [4]Division of Bio‑Medical Science&Technology,KIST School,University of Science&Technology(UST),Seoul 02792,South Korea

出　　处：《Nano-Micro Letters》2022年第2期60-78,共19页纳微快报（英文版）

基　　金：This work was supported by KIST(Korea Institute of Science and Technology)institutional grants(2E30965,and 2V07360);the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Nos.2020R1C1C1006065,2021M3F3A2A01037366);This work was also supported by the Korea Medical Device Development Fund grant funded by the Korea government(the Ministry of Science and ICT,the Ministry of Trade,Industry and Energy,the Ministry of Health&Welfare;the Ministry of Food and Drug Safety)(Project Number:9991006818,KMDF_PR_20200901_0145-2021).

摘　　要：Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs.The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)steps.First,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual microneedle.Then,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate.Subsequently,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures.Depending on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the substrate.With these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si wafer.Insertion tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain.To demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding processes.The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on.

关 键 词：MICRONEEDLE Various heights Cross-sectional shapes Isotropic etch Deep reactive ion etching 

分 类 号：TH789[机械工程—仪器科学与技术]