Artificial bacterial flagella: Fabrication and magnetic control

TLDR

Self‑propelled devices such as these are of interest in fundamental research and for biomedical applications. The authors report artificial bacterial flagella that mimic natural flagella in shape and size and can swim controllably under weak magnetic fields. The ABF comprises a helical tail and a soft‑magnetic head, and its locomotion is precisely controlled by three orthogonal electromagnetic coils while thrust is quantified via microsphere manipulation. These ABF swimmers constitute the first demonstration of microscopic artificial swimmers using helical propulsion.

Abstract

Inspired by the natural design of bacterial flagella, we report artificial bacterial flagella (ABF) that have a comparable shape and size to their organic counterparts and can swim in a controllable fashion using weak applied magnetic fields. The helical swimmer consists of a helical tail resembling the dimensions of a natural flagellum and a thin soft-magnetic “head” on one end. The swimming locomotion of ABF is precisely controlled by three orthogonal electromagnetic coil pairs. Microsphere manipulation is performed, and the thrust force generated by an ABF is analyzed. ABF swimmers represent the first demonstration of microscopic artificial swimmers that use helical propulsion. Self-propelled devices such as these are of interest in fundamental research and for biomedical applications.