Acoustic tweezers
Acoustic tweezers is a technology that is able to control the movement of objects by sound waves. In a standing acoustic field, objects will experience an acoustic radiation force that moves the objects to special regions of the acoustic field. Depending on the properties (density, compressibility) of the objects, they can be moved to either acoustic pressure nodes (minimum pressure regions) or pressure antinodes (maximum pressure regions). As a result, precise manipulation of objects using sound waves is feasible by controlling the position of pressure nodes. Acoustic tweezers does not require expensive equipment and complex experimental setups. More importantly, acoustic waves have been proven safe to biological objects, making it an ideal tool for biomedical applications. In recent years, acoustic tweezers finds many important applications in the area of manipulating sub-millimeter objects, such as flow cytometry, cell separation, cell trapping, single-cell manipulation, and nanomaterial manipulation.