Biosafety of micro/nanomotors towards medical application

Micro/nanomotors (MNMs) have attracted tremendous interest of researchers owing to their ability to mimic the function of natural microorganisms to complete tasks in biomedicine and other fields. However, in order to realize their practical use in the biomedical field, MNMs are required to meet the biosafety standard, which has not been systematically reviewed. The most important thing of concern for biosafety is to fabricate MNMs with good biodegradability, biocompatibility and biosafe propulsion. We reviewed the state-of-the-art of biosafe MNMs, focusing on the biodegradability, biocompatibility, biosafe propulsion and biosafety assessments of MNMs. The challenges and opportunities of biosafe MNMs for biomedical application are discussed.