High density cleanroom-free microneedle arrays for pain-free drug delivery

The purpose of this work is to demonstrate the fabrication process for cleanroom-free solid metal microneedles and perform quantification of insertion profiles. Metal microneedles were created using a modified wirebonding process and inserted into porcine tissue to determine design efficacy. Microneedle arrays were analyzed through optical imaging and scanning electron microscopy. Insertion forces were measured using combined uniaxial load cell and resistance measurement data. Microneedle arrays were successfully inserted into porcine tissue with high repeatability and reliability. These arrays demonstrate lower or equivalent insertion forces (less than 3 N) to other forms of microneedles in the literature without the need for complex cleanroom fabrication processes. The microneedle fabrication method presented here rapidly produces mass manufacturable, high-quality microneedle arrays with minimal insertion forces, able to reliably penetrate tissue samples. The manufacturing method presented here achieved array densities as high as 3200 needles cm−2. These microneedle arrays demonstrate simple fabrication of a reliable, high-density, pain-free drug delivery system, with potential applications in biosensing and electric field modulated drug delivery.