Index of content:
Volume 117, Issue 5, May 2005
- NONLINEAR ACOUSTICS 
117(2005); http://dx.doi.org/10.1121/1.1874592View Description Hide Description
A method is presented to position and displace micron-sized particles of a diameter between 10 and 100 μm without contact to solid instruments. An ultrasound field is utilized for this purpose. It is excited in a fluid-filled gap between a harmonically vibrating body and a rigid plane surface of an arbitrary other body, e.g., an object slide or a wafer. In this ultrasound field a force field is established, which acts on the particles suspended in the fluid and moves them to certain positions. The advantage of the method is that it is possible to manipulate single particles or many particles in parallel on any surface, for example, on a structured wafer. Theoretical calculations of the force field and experimental results including three principles to displace particles with micrometer accuracy are shown. The method might be used for microassembly or cell manipulation and treatment.