DLP 3D printing of high-resolution, temperature-responsive hydrogel microneedles with rapid customization capability

Hydrogel microneedles (MNs) are emerging as versatile transdermal drug delivery platforms for the treatment of various diseases. However, their conventional preparation method is plagued by a complex process, time-consuming nature, and low resolution. To address these challenges, we present a novel method for preparing temperature-responsive hydrogel MNs using a Digital Light Processing (DLP) strategy. The printed NIPAM-AA-AM hydrogel MNs can be rapidly customized (within 1 hour) into various shapes and heights with high resolution. The mechanical tests and H&E staining validate the ability of the MNs to penetrate the skin. In addition, the temperature-responsive drug delivery of the MNs was demonstrated through experiments and COSMOL simulations. Notably, these biocompatible microneedles showed non-toxicity in NIH-3T3 cells and low hemolysis rates, thereby indicating promising prospects for safe in vivo utilization. This study offers a simple and rapid alternative for the fabrication of smart responsive microneedles, opening up new avenues in personalized and efficient transdermal drug delivery strategies.