Magnetic Microswarms with Controlled Locomotion in Liquid and Air Environments

Abstract

Magnetic microswarms have attracted significant attention in medical robotics, owing to their potential for performing complex tasks in challenging environments. However, developing microswarms that can operate effectively in both liquid and air environments remains a substantial challenge. This study presents the design and characterization of hydrogel-based microswarms composed of magnetic hydrogel particles prepared from agarose hydrogel and NdFeB magnetic microparticles. These microswarms form stable monolayer structures actuated by rotating magnetic fields at high frequencies (10 Hz) in liquid environments, enabling synchronization with the external magnet and achieving translational motion. Actuated by an oscillating magnetic field, the swarms transition from a monolayer configuration to a three-dimensional (3D) structure in the air environment. Experimental results demonstrate that the 3D swarms are capable of navigating complex terrains and interacting with tissue surfaces in air environments. Finally, we demonstrate the potential of these 3D swarms for targeted delivery and adaptive filling of gastric perforations using an ex vivo gastric tissue model, showcasing their potential for biomedical applications.