Bionic microneedles: Design inspired by bionics and its applications in medicine

Microneedles (MNs) represent a novel approach to transdermal drug delivery, employing micron-scale structures to penetrate the stratum corneum and bypass the natural skin barrier. This approach combines the inherent advantages of transdermal delivery with significantly improved transport efficiency across the skin barrier. However, the widespread clinical adoption of MN technology is hindered by several technical barriers, including insufficient structural integrity, poor adhesion, inaccurate drug delivery, and unpredictable release profiles. Furthermore, bionics offers promising solutions for creating more efficient, intelligent, and environmentally friendly technologies. By integrating bionic principles with MN technology, novel bionic MNs have been developed, endowing conventional MNs with enhanced structures, properties, and functionalities to address the shortcomings of traditional systems. Inspired by natural elements, such as mantis claws, snake fangs, and coral, these bionic MNs overcome many limitations of conventional MNs and provide innovative solutions for clinical applications. This review systematically examines recent advances in bioinspired microneedle systems, highlighting innovative structural designs that optimize penetration capability through enhanced mechanical properties and improve tissue adhesion and multifunctional performance. Furthermore, it discusses the medical applications of bionic MNs in drug delivery, wound healing and tissue regeneration, as well as biomonitoring and biosensing. More importantly, we analyzed the existing limitations and development trends in each section to promote future research and the clinical translation of bionic MNs.