Selective Actuation for Microrobots Based on Distributed Magnetic Field Design

Abstract

Mechanical stimulation is essential for regulating cellular processes such as proliferation, differentiation, and apoptosis. Magnetic microrobot swarms offer a promising platform for delivering targeted mechanical stimulation to cells via remote actuation under rotating magnetic fields. However, magnetic fields globally activate swarms in non-target regions, risking undesired biological effects. To overcome this limitation, we propose a spatially selective magnetic actuation strategy that confines mechanical stimulation to user-defined regions. A dual-robotic-arm magnetic actuation system is developed to generate a selective rotating magnetic field. The field ensures swarms have smooth rotation and longer chain formation within the target area, enabling effective mechanical stimulation, while swarms outside exhibit shortened chains and disordered motion. We further demonstrate that the area swept by the rotating chain of microrobots peaks within the targeted region but drops sharply beyond it. This approach provides a foundation for precise mechanostimulation in biomedical applications with minimal off-target effects.