Figure 5.

Different designs of bubble propulsion. (A) Long-lasting armored microbubble under forced vibration. (B) Scanning electron microscopy images of the microrobot. The simulated acoustic pressure map at the resonance frequency. (C) The low-power acoustic field actuation oscillatory motion of a bubble enables directional motion in water. Two microswimmers with bubbles of different sizes enable independent control of each body. (D) Schematic diagram of proposed drug delivery technology. Reproduced with permission from Refs. [8,59,60,61], respectively.