Bioinspired micro/nanomotors towards a self-propelled noninvasive diagnosis and treatment of cancer

The last two decades have witnessed an extensive exploration of micro/nanomotors for an effective biomedical diagnosis and therapy. A nanomotor is a tiny smart device inspired by a biological motor that shows in situ energy conversion due to its own movements. Scientists are aiming for more innovative designs of these bioinspired nanomotors towards developing a self-propelled biomedical device that can perform various applications from drug delivery, biosensing to a therapeutic treatment of disease target, where actions can be driven easily by different energy sources, including biochemical, optical, magnetic, and electric fields. Herein, we review the recent development of bioinspired micro/nanomotors for biomedical applications with an aim to better understand the exact mechanism of motor propulsion and to establish a proper command over the motion, direction and speed. Firstly, we highlight energy sources being used for the propulsion of micromotors. Next, we discuss the establishment of micro/nanomotors as an intelligent and comprehensive biomedical nanodevice for the diagnosis and treatment of cancer. Recent studies show that these micro/nanomotors can navigate promptly to target cancer cells, penetrate through the cell membrane, reach up to the cytoplasm and isolate the circulating cancer cells, leading to rapid and ultrasensitive detection. The unique advantages and shortcomings of the differently designed nanomachines are also discussed. Lastly, we present our perspective and highlight the challenges in implementing micro/nanomotors for clinical applications in a real-world environment. It is anticipated that these bioinspired nanomachines/microrobots would be self-propelled and perform multi-tasking, which could help surgeons or physicians to perform challenging and timely tasks for the noninvasive diagnosis and treatment of cancer in future nanomedicine.