Fig. 19.

a Schematic and image of particle trapping in a single-node acoustic trap. Fluorescently (green) labelled particles are retained in a single cluster in the centre of the channel. Adapted and reproduced from [37] with permission from the Royal Society of Chemistry. b Schematic and image of particle trapping in a multi-node acoustic trap. Fluorescently (green) labelled particles are retained in multiple distinct clusters along the height direction of the channel, corresponding to the pressure nodes in the standing wave. Figure adapted and reprinted from [43]