Assembly, Disassembly, and Anomalous Propulsion of Microscopic Helices

Controlling the motion of small objects in suspensions wirelessly is of fundamental interest and has potential applications in biomedicine for drug delivery and micromanipulation of small structures. Here we show that magnetic helical microstructures that propel themselves in the presence of rotating weak magnetic fields assemble into various configurations that exhibit locomotion and a change in swimming direction. The configuration is tuned dynamically, that is, assembly and disassembly occur, by the field input. We investigate a system that consists of two identical right-handed helices assembled at their center in order to model the motion on both the component design and the assembly configuration. direction emerges, yet with other designs, a reversal in motion structures enables uni- and multidirectional navigation of this of assembled swimmers. The swimming properties are dependent For particular designs and configurations, a reversal in swimming never appears. Understanding the locomotion of clustered chiral class of active suspensions.