A novel mask-less method of fabricating high aspect ratio microneedles for blood sampling

The lack of safe, reliable, automated and clinically acceptable blood sampling has been the main problem impeding the development of real-time systems for blood analysis and subsequent closed-loop physiological function control. A key component of a real-time implantable blood sampling microsystem is a microneedle array which directly interfaces with the electronics and tissue. The primary motivation for the development of the microneedle is the need for needles that are economical to fabricate, and are small enough to reduce insertion pain and tissue trauma. Microsystem technology is well suited for batch fabrication of microneedles, intended for blood sampling. In the past decade microneedles have been produced using fixed lithographic mask sets, which is straightforward, but costly for small production volumes. We demonstrate a novel method to fabricate high throughput, three dimensional microneedle arrays with a mask-less process. In this paper we have used laser machining, dicing and wet etching to fabricate high density microneedle arrays.