Autonomous Navigation of Pollen‐Inspired Magnetic Microrobots for Biomedical Applications

Recent advances in microrobotics have expanded opportunities for biomedical delivery, but reliable navigation in complex microvascular environments remains challenging, particularly when continuous imaging is limited. Here we develop a sunflower pollen‐inspired magnetic microrobot for targeted delivery and tissue engineering applications. Fabricated by two‐photon polymerization and coated with nickel and titanium for magnetic actuation and biocompatibility, the 40 µm microrobot features an open, hydrodynamic geometry that facilitates cell adhesion through its surface topology. Finite‐element analysis supported this design rationale, showing 4.45‐fold lower translational drag and 4.1‐fold lower rotational hydrodynamic resistance than a solid spherical microrobot of the same outer diameter. We demonstrated stable rolling under physiologically relevant flow conditions, including upstream motion against opposing flow, and evaluated autonomous navigation in static and dynamic environments using a vision‐based closed‐loop controller combined with reinforcement learning. The system enabled trajectory tracking, shortest‐path selection, and multiturn maze navigation with microrobot‐scale error. By combining efficient rolling locomotion with navigation based on intermittent visual updates, this platform supports microrobot guidancein future minimally invasive interventions where continuous monitoring is restricted.