The acoustically propelled motion of the LMGNSs. (a) The relationship between the motion velocity of LMGNSs and frequency of acoustic field at 10 V. (b) Time-lapse image of a LMGNS at an applied voltage of 10 V and an ultrasound frequency of 420 kHz. Inset is fluorescent time-lapse image of a LMGNS under same condition. (c) The time-lapse images of frequency determined direction control of LMGNSs. (d) The direction changes of LMGNSs during frequency changing. The inset images show the LMGNS 2 at 0.83, 0.93, 1.17, and 1.33 s. (e) The relationship between motion velocity LMGNSs and the applied voltage of acoustic field. Scale bars, 20 μm.