“…As an alternative to mechanical pumps and valves, using acoustics has been proposed . In an acoustic microfluidic ( acoustofluidic ) chip, ultrasound transducers create acoustic waves, which can be used for transporting particles, − cells, − or droplets. − More than just transporting, acoustics can also be used for sorting particles ,, or droplets, merging droplets, ,, and splitting droplets. − Manipulating multiple solid objects by shaping the acoustic fields has been demonstrated, e.g., by using holographic acoustic traps ,, or by using time-varying signals. ,, Objects can be manipulated acoustically on the surface of the device or within a medium, using transverse waves, ,, bulk acoustic waves, ,, or surface acoustic waves. ,,, …”