Reconfigurable Cilia-Based Magnetic Millirobots for Cooperative Particle Manipulation Through Programmable Assembly in Microfluidics

Reconfigurable robotic systems have emerged as platforms for particle manipulation owing to their adaptability and capability to alter structural configurations according to task requirements. However, achieving programmable particle capture, transportation, and release through cooperative interactions among untethered robots within microfluidic environments remains challenging. In the present study, reconfigurable cilia-based magnetic millirobots (CMMRs) were developed for cooperative particle manipulation through programmable assembly. The platform consisted of multiple CMMRs that were independently actuated using an electromagnetic coil array and assembled into a cooperative structure possessing a central cavity for particle confinement. Through sequential electromagnetic coil activation and pulse-width modulation-based control, programmable assembly, transportation, and disassembly of the CMMRs were achieved. During assembly, self-organization analysis demonstrated that the constituent CMMRs converged toward this configuration, enabling formation of the cooperative structure needed. Subsequently, particle transportation experiments demonstrated the confinement and transportation of particles along predefined trajectories, with trajectory deviations maintained below 5%. Furthermore, μPIV characterization revealed that the assembled structure generated a directional transport corridor with a flow velocity of 4.5 mm s−1, providing a hydrodynamic environment for particle transportation compared with individual CMMRs. The demonstrated capabilities can serve as a foundation for reconfigurable untethered robotic systems capable of microhandling operations in lab-on-a-chip environments.