Producing Hollow Polymer Microneedles Using Laser Ablated Molds in an Injection Molding Process

Abstract

Microneedle arrays contain needlelike microscopic structures, which facilitate drug or vaccine delivery in a minimally invasive way. However, producing hollow microneedles is currently limited by expensive, time consuming and complex microfabrication techniques. In this paper, a novel method to produce hollow polymer microneedles is presented. This method utilizes a femtosecond laser to create hollow microneedle cavities in a mold insert. This mold insert is used in an injection molding process to replicate polymethyl methacrylate microneedles. The combined effect of the mold temperature, volumetric injection rate, and melt temperature on the replication fidelity was evaluated. It was found that the combination of high injection molding parameters facilitated the replication. Furthermore, the functionality of the manufactured hollow microneedles was successfully tested by injecting a controlled flow of colored water into an agarose matrix. The developed methodology enables the production of low-cost, high-volume microneedle devices, which could be a key asset for large scale vaccination campaigns.