Capturing, carrying, and releasing of objects by an oscillating mobile bubble. (a)-(b) The piezo-actuator oscillates the gaseous bubble such that circulating flows are generated around the bubble (so called "cavitational microstreaming"), and then the neighboring objects are captured in and orbiting in the circulating flows. (c) As EWOD electrodes are sequentially activated to the right, the bubble is moved right. Note that the piezo-actuator is still on while the bubble is moving. As a result, the captured particles are carried by the moving bubble. (d) When the piezo-actuator is off, the continued bubble transportation completely separates the captured particles from the bubble.