Bioinspired claw-engaged and biolubricated swimming microrobots creating active retention in blood vessels

Swimming microrobots guided in the circulation system offer considerable promise in precision medicine but currently suffer from problems such as limited adhesion to blood vessels, intensive blood flow, and immune system clearance-all reducing the targeted interaction. A swimming microrobot design with clawed geometry, a red blood cell (RBC) membrane-camouflaged surface, and magnetically actuated retention is discussed, allow-ing better navigation and inspired by the tardigrade's mechanical claw engagement, coupled to an RBC mem-brane coating, to minimize blood flow impact. Using clinical intravascular optical coherence tomography in vivo, the microrobots' activity and dynamics in a rabbit jugular vein was monitored, illustrating very effective mag-netic propulsion, even against a flow of similar to 2.1 cm/s, comparable with rabbit blood flow characteristics. The equiv-alent friction coefficient with magnetically actuated retention is elevated similar to 24-fold, compared to magnetic microspheres, achieving active retention at 3.2 cm/s, for >36 hours, showing considerable promise across bio-medical applications.