Unique benefits and challenges of 3D-printed microneedles

Microneedles, which are used in minimally invasive transdermal drug delivery, have tremendous application potential in the fields of biosensing, disease diagnosis, bioelectrical signal detection, and wound management. Although manufacturing methods for microneedles are technically well-established, continuously evolving scientific and clinical applications require more intricate and bespoke microneedle structures that cannot be fabricated using conventional techniques. Threedimensional (3D) printing is an advanced manufacturing technology capable of automatically fabricating microneedles with intricate structures. This review provides a comprehensive overview of 3D printing methods and, materials, as well as the mechanical properties and biocompatibility of 3D-printed microneedles, with a particular focus on their inherent advantages and limitations. This offers insights into future trends and strategies for expediting the clinical adoption and commercialization of 3D-printed microneedles.