Schematic diagram of manipulation of microparticles with two different sizes by utilizing an optothermally and acoustically excited bubble on-demand. (a) Dispersed microparticles with different sizes. (b) Generation of a bubble through optothermal effects. (c) Transportation of the bubble toward the dispersed microparticles by using optothermocapillary effects. (d) Sorting and capturing of target particles with a specific size by means of acoustic radiation effects. (e) Transportation of captured particles through both optothermocapillary and acoustic radiation effects. (f) Releasing captured particles in the absence of acoustic agitation and subsequent return to the original position by way of optothermocapillary effects.