Design and Fabrication of Microneedles for Drug Delivery

Abstract

The microneedle array with biodegradable porous tips was designed and fabricated for transdermal delivery. Silicon microneedles with sharp tips were fabricated by an isotropic etching process in an inductively coupled plasma (ICP) etcher. The biodegradable porous tips were then fabricated by an optimized anodic electrochemical etching process. An analytical model was established to predict the critical loadings for microneedle during insertion. A microsystem consisting of a hollow silicon microneedle array and glass pump components was further developed for injection. Dimensions for the inner channel and actuator mechanism were designed to deliver a desired flow rate. A high aspect ratio, hollow microneedle array was fabricated using a dual-step dry etching process which includes deep reactive ion etching (DRIE) and isotropic etching. In addition, an optimized HF/HCL solution was developed to fabricate the glass components.