Optoelectronic Tweezers Push Nanowires Around

In efforts that can improve studies of biological objects and the construction of nanotech materials, a Berkeley group has invented "optoelectronic tweezers," a new way of controlling nanometer-scale objects. Optoelectronic tweezers, which use optical energy to create powerful electric forces in carefully prescribed places, differ from ordinary "optical tweezers," which use optical energy to create mechanical forces that can push things around.

According to Berkeley's Aaron Ohta, the optoelectronic approach uses much less power than optical tweezers and the light doesn't need to be as carefully focused, helping to make the technique potentially easier for laboratories to implement. In recent months the Berkeley group has had some success in using their locally controlled electric fields to manipulate the positions of tiny nanorods, or nanowires (100 nm in diameter and 1-50 microns long).

Ohta says that the optoelectronic device will possibly be used to place nanorods for the sake of building 3-D circuitry or for positioning oblong-shaped cells or cell protrusions with micron-level precision. (Paper CThGG5; for more information, see Chiou et al., Nature, 21 July 2005 and http://www.cleoconference.org/media_center/April27Release.aspx )