Stimuli-Responsive Functional Micro-/Nanorobots: A Review

Stimuli-responsive functional micro-/nanorobots(srFM/Ns) are aclass of intelligent, efficient, and promising microrobots that canreact to external stimuli (such as temperature, light, ultrasound,pH, ion, and magnetic field) and perform designated tasks. Throughadaptive transformation into the corresponding functional forms, theycan perfectly match the demands depending on different applications,which manifest extremely important roles in targeted therapy, biologicaldetection, tissue engineering, and other fields. Promising as srFM/Nscan be, few reviews have focused on them. It is therefore necessaryto provide an overview of the current development of these intelligentsrFM/Ns to provide clear inspiration for further development of thisfield. Hence, this review summarizes the current advances of stimuli-responsivefunctional microrobots regarding their response mechanism, the achievedfunctions, and their applications to highlight the pros and cons ofdifferent stimuli. Finally, we emphasize the existing challenges ofsrFM/Ns and propose possible strategies to help accelerate the studyof this field and promote srFM/Ns toward actual applications.