Versatile non-contact micro-manipulation method using rotational flows locally induced by magnetic microrobots

We present a versatile non-contact micromanipulation approach using the rotational flows locally induced by rotation of spherical magnetic microrobots in liquid environments. Micro-scale objects in close vicinity to the rotating microrobot are trapped inside the induced rotational flows and carried along with the robot as it translates on a planar surface by rotational motion. The proposed approach can handle a wide range of object sizes, and manipulate objects larger than the robot and significantly denser than water. Trapping and transport of individual human myeloid leukemia cells and swimming flagellated bacteria using this method has also been demonstrated. The proposed approach requires no special surface pattern or spatial structure, and hence is directly compatible with existing microfluidic devices.