Adaptive Ferrofluidic Robotic System with Passive Component Activation Capabilities.

Soft robots demonstrate remarkable potential in medical applications owing to their minimally invasive nature, exceptional controllability, and shape-adaptive capabilities. However, existing control systems primarily rely on a single permanent magnet or electromagnetic coil for actuation, resulting in limited robotic motion capabilities, weak electromagnetic field gradient forces, and bulky magnetic drive systems. These constraints substantially hinder the robot's flexibility and functional expandability. To address these constraints, this study proposes a highly integrated hybrid electromagnetic coil permanent magnet actuation system. This innovative design enables actuation force amplification and synergistic regulation of locomotion, deformation, and orientation. Experimental validation confirms the broad operational capacity of the miniature ferrofluidic robot (MFR), including controllable motion-deformation coupling within multiscale luminal structures and active directional control in biomimetic gastric models. Leveraging the MFR's robust deformation and locomotion abilities, the empowerment mechanism for passive structures significantly enhanced compatibility with mechanical systems. Based on this mechanism, we achieved the transportation of larger-mass simulated drug particles by empowering passive delivery systems. To further validate the functionality of MFR, we developed an MFR-based capsule that achieves precise temporal and spatial control of drug release through experiments involving magnetothermal effect-accelerated release of simulated drugs and selective occlusion in simulated blood vessels. These advancements markedly enhanced the application potential of microrobots in complex and confined clinical environments.