Rotating magnetic micro-robots for versatile non-contact fluidic manipulation of micro-objects

This work introduces new strategies for fluid-based manipulation of micro-scale objects using rotating magnetic micro-robots at low Reynolds numbers. By rapidly spinning the micro-robots, rotational fluid flow is induced which acts to move the micro-objects by fluidic drag. Acting in parallel, teams of these micro-robots are shown to work together to rapidly move micro-objects along planned “virtual channel”s to goal positions. As the micro-robots are themselves highly mobile, the manipulation trajectories are controlled to achieve accurate, fast manipulation of multiple micro-objects in 2-D environments. Experiments are performed in a viscous oil (50 cSt) to simulate the physics of micro-robots which are small enough to fit through small micro-fluidic channels or blood capillaries. The micro-robot and micro-object motions are characterized to support the proposed strategies. Spherical micro-robots 380µm in diameter are used to manipulate 200µm diameter particles with controllable speeds of up to 3.5 mm/s.