Externally controlled intermittent randomization enables complex navigation of multiple nanobots

Selective control of single untethered robots within a collection is trivial in macroscale robotics since it is possible to address and actuate individual entities using various communication schemes. This strategy does not work at reduced (sub-µm) length scales, where the global field cannot differentiate or control a single nanobot selectively from within a collection of indistinguishable objects. Here, we propose and demonstrate strategies where identical magnetic nanobots can be selectively and independently actuated using global control fields. A key challenge for submicrometer magnetically actuated devices is achieving individual control under a global field. The authors present strategies to selectively and independently actuate identical nanobots, enabling distinct motions and complex collective behaviors at the nanoscale.