Fabrication of high-density microneedle masters towards the commercialisation of dissolving microneedles

Recent progress of dissolving microneedles opens up a great potential for the utilisation of microneedles in a wide range of applications. However, the commercialisation of dissolving microneedles requires mass production of microneedle masters and moulds. In this work, a simple, low-cost and high-throughput fabrication method of high-density microneedle masters is presented. The high-density microneedle masters were fabricated by first machining an aluminium workpiece to form high-density rectangular column arrays using wire-cut electrode discharge machining. Subsequently, the rectangular column arrays were subjected to a chemical etching under a mass-transport limited condition resulting in the formation of conical-shaped microneedle masters without the need of etch mask. For demonstration, the fabricated microneedle masters were used as a template for the fabrication of an inverse polymer mould and subsequently the polymer mould was used for the fabrication of silk microneedles. The proposed method offers a simple, low cost and high throughput means for the mass production of high-density microneedle masters towards the commercialisation of dissolving microneedles.