A Perspective on acoustical tweezers-devices, forces, and biomedical applications

Acoustical tweezers are devices that use acoustic radiation forces to trap and maneuver objects. This Perspective focuses on the biomedical applications of these devices, and hence, the target objects include cells, cell clusters, and micro-organisms. These objects are of microscopic size and have acoustic properties similar to the water-like biological media in which they are found. The character of the acoustic radiation forces is first discussed as is a selection of the expanding range of biomedical applications. Future directions are then described, which include increased integration of acoustical tweezers with other biomedical technology, approaches that allow increased functionality at the single-cell level, and a move toward quantitative measurements such as cell stiffness.