Recent progress on the design and fabrication of micromotors and their biomedical applications

The advancement in the micro-/nanofabrication techniques has greatly facilitated the development of micromotors. A variety of micromotors have been invented with powerful functions, which have attracted a broad range of interests from chemistry, physics, mechanics, biology and medicine. In this paper, we reviewed recent progress in micromotors and highlighted representative works. The mechanisms of micromotors by internal and external energy sources were described. We described general fabrication strategies of the popular micromotors (wire, tubular, helical and Janus) including bottom-up and top-down approaches. In the application section, we primarily focused on the biological applications, such as biological cargo delivery, biosensing and surgery. At last, we discussed the current challenges and provided future prospects.