A VERSATILE ROUTE FOR THE FABRICATION OF SILICON MICRONEEDLES FOR TRANSDERMAL APPLICATIONS BY ELECTROCHEMICAL MICROMACHINING TECHNOLOGY

In this work, we report a novel, versatile, and low-cost approach for the fabrication of both “flat” and “sharp” out-of-plane silicon microneedles for transdermal applications. Unlike state-of-the-art microneedles reported so far, the microneedles of this work feature a built-in reservoir in the needle-core to be used for drug storing and deliv-ery after insertion in the skin. The microneedles, with height of about 100 µm and density between 625 needles/cm2 (spatial period of 400 µm) and 40000 needles/cm2 (spatial period of 50 µm), are effectively fabri-cated by silicon electrochemical micromachining technology. In-vitro insertion tests carried out on both synthetic and hairless-mouse skins clearly demonstrate penetration efficacy and reliability of such tiny needles, which are up to ten times thinner than a human hair