Candidate: Fahima Tazrin
Title: Fabrication of Silicon In-Plane and Out-of-Plane Microneedle Arrays for Transdermal Biological Fluid Extraction
Date: March 13, 2019
Place: EIT 3145
Supervisor(s): Cui, Bo
My latest work presents in the field of microelectromechanical systems and specifically in the area of microneedle-based transdermal skin fluid extraction and drug delivery. The main objective of this research is to highlight the potential role of microneedles in achieving painless transdermal skin biofluid extraction and drug delivery of macromolecular drugs across the skin barrier. The work represents the design and fabrication of silicon out-of-plane and in-plane microneedles and an innovative double-side Deep Reactive Ion Etching (DRIE) approach was presented for producing hollow silicon microneedle arrays for transdermal biological fluid extraction. The solid silicon out-of-plane microneedles are fabricated from a single side polished wafer whereas the hollow out-of-plane microneedles are fabricated from a double side polished wafer to a shank height of 200-300 m with 300 m center-to-center spacing. The single-step Bosch DRIE is performed for “in-plane” silicon microneedles to simultaneously etch the needle shaft (parallel to silicon substrate, etch through the wafer) and the narrow trenches as open capillary fluidic channels (partly etched into the wafer), taking advantage of the aspect-ratio dependent DRIE etching.
Furthermore, the double-sided two stage DRIE is performed to etch the open trenches on the backside of wafer and then the needle shaft on the front side. The in-plane needles have the advantages of making long needles up to 2 mm. Moreover, the in vivo testing results are provided as well.
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