Self-Assembly and Collective Locomotion Behavior of Swarm Microrobot.

Collective behaviors in microrobots achieve self-assembly and execute complex tasks through swarm microrobot interactions and collaboration, which possess significant potential in biomedical applications. However, challenges such as swarm stability and diversity, and adaptability to complex environments remain to be addressed. In this study, magnetically anisotropic hydrogel microrobots are developed to explore the potential of assembly behavior and collective locomotion driven by the interactions of multiple microrobots. In this, microrobots with distinct magnetic particle arrangements exhibit different critical frequencies under magnetic fields, which play a pivotal role in governing their assembly behavior and collective locomotion. By categorizing microrobots with varying critical frequencies into separate units, the dynamic behaviors and collective modes of these units are investigated under rotating magnetic fields. Through precise regulation of magnetic field parameters and analysis of interaction mechanisms, efficient and stable collective modes are demonstrated. Furthermore, diverse collective modes and reversible self-assembly dynamics of swarm microrobots are comprehensively investigated, with a specific focus on the biomedical application of linearly arranged microrobot swarms in targeted delivery. This work proposes a novel approach for achieving static assembly and controlled collective locomotion in microrobots, offering innovative insights into the design and implementation of swarm microrobots for biomedical engineering applications.