Magnetically actuated micro swimming of bio-inspired robots in mini channels

Untethered swimming microrobots have many advantages for biomedical applications such as targeted drug delivery, simple surgical tasks including opening of clogged arteries and as diagnostic tools. In this paper, swimming of microrobots is examined in water and glycerin filled channels. Propulsion of microrobots is enabled by means of an external magnetic field that rotates in the axial direction of the channel and forces robots to rotate about the axis of the helical tail. Rotation of the helical tail resulted in a screw-like motion of the robot reaching speeds up to several millimeters per second for a 2-mm long robot. The results are compared with resistive force theory, which is based on the assumption that the propulsive force resulting from the rotation of the helix is proportional to the local velocity on the helical flagellum in low Reynolds number micro and viscous flows.