Motion control of artificial bacterial flagella

Miniaturized helical swimmers we call artificial bacterial flagella (ABFs) are promising for biomedical applications, such as targeted drug delivery and cell manipulation. ABFs possess several advantageous characteristics, such as high swimming velocity and precise motion control, indicating their potential for diverse applications. The velocity and the propulsive force of ABFs can be controlled by the input frequency of the rotating magnetic field that powers them. In this paper the motion control of two types of ABF, i.e. nanobelt based ABFs (NB-ABFs) and nanowire based ABFs (NW-ABFs), is reported. For NB-ABFs the swimming behavior at frequencies near the step-out frequency is investigated. Experimental results indicate that the non-ideal swimming motion of the ABF at frequencies higher than the step-out frequency is promising for the decoupling of specified ABFs from a swarm. The NW-ABF is achieved by magnetic assembly of two bent Ni nanowires. The results show that the motion of the NW-ABF is controllable by a rotating magnetic field.