Remote control of self-assembled microswimmers

TL;DR

This paper demonstrates that a self-assembled system of ferromagnetic beads can be magnetically controlled to swim at a liquid-air interface, enabling precise navigation and potential applications in microscale transport.

Contribution

It introduces a novel magnetocapillary-driven self-assembly system capable of controlled microswimming at low Reynolds numbers.

Findings

Self-assembled ferromagnetic beads can swim at liquid-air interfaces.

External magnetic fields enable full control of trajectories.

The system allows potential applications like cargo transport.

Abstract

Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the considered body. Here, we show that a magnetocapillary-driven self-assembly, composed of three soft ferromagnetic beads, is able to swim along a liquid-air interface when powered by an external magnetic field. More importantly, we demonstrate that trajectories can be fully controlled, opening ways to explore low Reynolds number swimming. This magnetocapillary system spontaneously forms by self-assembly, allowing miniaturization and other possible applications such as cargo transport or solvent flows.