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Proceedings Paper

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery
Author(s): H. B. Ng; C. Shearwood
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Paper Abstract

The successful development of micro-needles can help transport drugs and vaccines both effectively and painlessly across the skin. However, not all micro-needles are strong enough to withstand the insertion forces and viscoelasticity of the skin. The work here focuses on the micro-fabrication of high aspect ratio needles with careful control of needle-profile using dry etching technologies. Silicon micro-needles, 150μm in length with base-diameters ranging from 90 to 240μm have been investigated in this study. A novel, multiple-sacrificial approach has been demonstrated as suited to the fabrication of long micro-needle bodies with positive profiles. The parameters that control the isotropic etching are adjusted to control the ratio of the needle-base diameter to needle length. By careful control of geometry, the needle profile can be engineered to give a suitable tip size for penetration, as well as a broad needle base to facilitate the creation of either single or multiple-through holes. This approach allows the mechanical properties of the otherwise brittle needles to be optimized. Finite element analysis indicates that the micro-needles will fracture prematurely due to buckling, with forces ranging from 10 to 30mN.

Paper Details

Date Published: 27 December 2007
PDF: 8 pages
Proc. SPIE 6799, BioMEMS and Nanotechnology III, 67990O (27 December 2007); doi: 10.1117/12.758885
Show Author Affiliations
H. B. Ng, Nanyang Technological Univ. (Singapore)
C. Shearwood, Nanyang Technological Univ. (Singapore)

Published in SPIE Proceedings Vol. 6799:
BioMEMS and Nanotechnology III
Dan V. Nicolau; Derek Abbott; Kourosh Kalantar-Zadeh; Tiziana Di Matteo; Sergey M. Bezrukov, Editor(s)

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