Fabrication of hollow microneedles with jagged edges mimicking mosquito's needles by thermal nanoimprint method using a mold combining soft and hard materials

Abstract

Abstract In the aim of realizing minimally invasive needles, a hollow microneedle mimicking mosquito’s proboscis was developed by thermal nanoimprint method using PLA of biodegradable thermoplastic. A mold was proposed and developed, which consisted of soft PDMS body and hard acrylic center pillar for creating the hole. Note that if a mold is made of a single PDMS, the pillar cannot withstand the imprint pressure and tilts. By imprinting the mold against a PLA sheet, a hollow structure with high aspect ratio of 5, i.e., outer/inner diameter: 200/100 µm, height: 1,000 µm, with its sharp tip and jagged edge was successfully achieved.