High density and high aspect ratio solid micro-nanoprojection arrays for targeted skin vaccine delivery and specific antibody extraction

We introduce and describe a methodology for fabricating high-density and high aspect ratio micro-nanoprojection arrays—and further demonstrate the utility of these devices in targeting the skin for two different healthcare applications. The key to achieving the unprecedented high projection density (>20 000 cm⁻²) is the use of a controlled mixed plasma in a DRIE process, producing long, tapered tips without limiting the overall feature density. With a tailored process we produce structures of tuneable shape and height, with high uniformity across the face of silicon wafers. We show that these devices are suitable for both biological delivery and biomarker-specific extraction applications.