Swarm control of cell-based microrobots using a single global magnetic field

Tetrahymena pyriformis is a single cell eukaryote that can be modified to respond to magnetic fields, a response called magnetotaxis. In experiments, a rotating field is applied to cells using a two dimensional approximate Helmholtz system. Using rotating magnetic fields, we characterize discrete cells´ swarm swimming which is affected by several factors. The behavior of the cells under these fields is explained in detail. After the field is removed, relatively straight swimming is observed. By exploiting this straight swimming behavior, we propose a method to control discrete cells utilizing a single global input. Successful implementation of this swarm control method would enable teams of microrobots to perform a variety of microscale tasks impossible for single microrobots, such as pushing objects or simultaneous micromanipulation of discrete entities.