Particle manipulation by phase-shifting of surface acoustic waves

•We demonstrate an acoustic-based method for manipulating particles using phase-shifting of surface acoustic waves.•The location of the pressure node is adjusted simply by modulating the relative phase difference (phase-shift) between two interdigital transducers (IDTs).•The particles trapped in the pressure node are manipulated laterally across the microfluidic channel.•The particle displacements as a function of the phase-shift are obtained experimentally and compared with the theoretical prediction of the particle position.

An acoustic-based method for manipulating particles using phase-shifting is demonstrated. The location of the pressure node was changed simply by adjusting the phase difference (phase-shift) applied to the two interdigital transducers in the design. As a result, polystyrene particles of 5 μm diameter trapped in the pressure node were manipulated laterally across the microchannel fabricated. The lateral particle displacement from −72.5 μm to 73.1 μm along the x-direction was accomplished by varying the phase-shift with a range of −180° to 180°. In this paper, the particle displacement as a function of the phase-shift of SAW was obtained experimentally and close agreement with the theoretical prediction of the particle position was demonstrated.