From conceptual design to translational progress: Emerging advances in intelligent microneedles for biomedical applications

Microneedles (MNs), as innovative biomedical devices, are undergoing a transformation from basic transdermal devices to intelligent and multifunctional systems. The advancement of intelligent MNs enhances tissue penetration and adhesion, triggers timely, on-demand and precise spatiotemporal controlled release, achieves sequential drug delivery and in situ monitoring, and enables close-loop theranostics via the integration of flexible electronics, wireless communication, and artificial intelligence. This review not only systematically highlights these cutting-edge breakthroughs, focusing on five major innovative advancements of conceptual design, including mimicking strategies, stimuli-responsive systems, innovative structural designs, living payload, and wearable integration, but also delineates the principal obstacles obstructing the advancement of intelligent MNs. We also emphasize that MN technology is fueling the evolution of next-generation medical paradigms based on its personalized, minimally invasive, and intelligent features through interdisciplinary integration, which is crucial for reshaping the future landscape of disease diagnosis and treatment.