Fabrication of Magnetic Microrobots by Assembly

Magnetic microrobots have gained significant attention in the biomedical field due to their wireless actuation, strong controllability, fast response, and minimal impact on the environment. As the task complexity keeps increasing in the clinical applications of magnetic microrobots, more geometric structures and magnetization profiles have been included in the designs of magnetic microrobots, posing significant challenges to the fabrication of magnetic microrobots. Microassembly is a fabrication method that can create convoluted structures with small-scale modules. It can accurately control the position and orientation of each magnetic module, resulting in a magnetic microrobot with arbitrary 3D geometries and magnetization profiles. This article reviews recent advanced assembly-based fabrication methods of magnetic microrobots, including microassembly driven by contact mechanical forces and noncontact field forces. The principles, fabrication processes, and the advantages and disadvantages of each assembly-based fabrication method are summarized. The existing challenges and future development of fabricating magnetic microrobots by assembly are discussed in detail. It is believed that this review will provide a methodological reference and inspire new ideas for manufacturing powerful magnetic microrobots in future biomedical applications.