Fabrication and characterization of gold coated hollow silicon microneedle array for drug delivery

Abstract

In this paper, we present the fabrication and characterization of Ti and Au coated hollow silicon microneedles for transdermal drug delivery applications. The hollow silicon microneedles are fabricated using isotropic etching followed by anisotropic etching to obtain a tapered tip. Silicon microneedle of 300μm in height, with 130μm outer diameter and 110μm inner diameter at the tip followed by 80μm inner diameter and 160μm outer diameter at the base have been fabricated. In order to improve the biocompatibility of microneedles, the fabricated microneedles were coated with Ti (500nm) by sputtering technique followed by gold coating using electroplating. A breaking force of 225N was obtained for the fabricated microneedles, which is 10 times higher than the skin resistive force. Hence, fabricated microneedles can easily be inserted inside the skin without breakage. The fluid flow through the microneedles was studied for different inlet pressures. A minimum inlet pressure of 0.66kPa was required to achieve a flow rate of 50μl in 2s with de-ionized water as a fluid medium.