MOF-based micro/nanomotors (MOFtors): Recent progress and challenges

Micro/nanomotors (MNMs) are burgeoning micro/nanoscale devices with plentiful applications ranging from biomedicine to environmental remediation. However, some urgent problems of these MNMs, such as high cost, low stability, poor loading/adsorption capability and uncontrollable motion, have not been ultimately solved. Owing to the high porosity, flexible and tunable structure, huge surface area, abundant binding sites and excellent chemical and thermal stability, metal-organic frameworks (MOFs) provide new alternatives into solving these problems of MNMs. Therefore, the past decade has witnessed the great achievement in the orchestration of MOF-based MNMs (MOFtors), with abundant applications in both biomedical and environmental fields. However, until now, there is few review dedicated to the systematic discussion on the synthetic approaches, propulsion mechanism, working principles, representative proof-of-concept applications, as well as the current challenges of MOFtors. Bearing it in mind and based on our research experience in this field, firstly, we summarized the synthesis methods of MOFtors. Then, we started from the discussion on functions and characteristics of MOFs, with further explorations on the applications of MOFtors. Finally, based on our understanding of this field, the challenges and outlook have been proposed, hoping to provide fundamental understanding for the future development of MOFtors.