Magneto–Acoustic Hybrid Nanomotor.

Efficient and controlled nanoscalepropulsion in harsh environments requires careful design and manufacturingof nanomachines, which can harvest and translate the propelling forceswith high spatial and time resolution. Here we report a new classof artificial nanomachine, named magneto–acoustic hybrid nanomotor,which displays efficient propulsion in the presence of either magneticor acoustic fields without adding any chemical fuel. These fuel-freehybrid nanomotors, which comprise a magnetic helical structure anda concave nanorod end, are synthesized using a template-assisted electrochemicaldeposition process followed by segment-selective chemical etching.Dynamic switching of the propulsion mode with reversal of the movementdirection and digital speed regulation are demonstrated on a singlenanovehicle. These hybrid nanomotors exhibit a diverse biomimeticcollective behavior, including stable aggregation, swarm motion, andswarm vortex, triggered in response to different field inputs. Suchadaptive hybrid operation and controlled collective behavior holdconsiderable promise for designing smart nanovehicles that autonomouslyreconfigure their operation mode according to their mission or inresponse to changes in their surrounding environment or in their ownperformance, thus holding considerable promise for diverse practicalbiomedical applications of fuel-free nanomachines. [ABSTRACT FROM AUTHOR]