Novel low cost fabrication of microneedle arrays for drug delivery applications

Abstract

This paper reports a process used for the microfabrication of an array of hollow microneedles. The purpose of the array is for painless transdermal drug delivery. The fabrication process uses wet bulk silicon technology and copper electroplating technology. First, a microneedle array mold on 〈100〉-oriented silicon was fabricated by wet anisotropic etching using KOH solution, then the silicon mold was electroplated with copper. After which, the hollow copper microneedle array was released by a lift-off process or by etching off the silicon mold in KOH solution. The hollow copper microneedle array has been mounted on a polycarbonate platform, which consist of laser ablated cavities and channel for external connection to drug source. In consideration of the contour of human's skin and the geometry of the microneedle tip, which has walls of sloping gradient corresponding to the (111)-planes, the height of the microneedle array is 200 μm. Two arrays of hollow copper microneedle were fabricated. They have square base of dimensions 390 μm and 400 μm and square tips of size 100 μm and 120 μm with square holes of size 88 μm and 94 μm respectively. Both arrays have microneedle tips at 1900 μm apart from one another and consist of 10 × 10 microneedle tips.