by PhilipJ on 22 July 2005
In today’s Nature, a new high throughput method for manipulating micrometer-scale particles is introduced, called optoelectronic tweezers (OETs)!
Current techniques can give you either high throughput or high resolution in terms of particle manipulation: optical tweezers have very high resolution (from single particles in conventional optical tweezers to a couple of hundred particles in the more recently developed Dynamic Holographic Optical Tweezers, while electrokinetic (electrophoresis, dielectrophoresis, etc) techinques are high throughput but you lose the ability to manipulate individual particles.
In OETs, liquid containing microscopic particles of interest is sandwiched between indium-tin-oxide glass (ITO) on the top and a photosensitive ITO-coated glass topped with amorphous hydrogenated silicon layers on the bottom. Through the use of a spatial light modulator, images (from an inexpensive incoherent light source) of any desire can be imprinted onto the bottom photosensitive glass layer, leading to dynamic optically-induced dielectrophoretic forces on the objects sandwhiched between the glass. Up to 15,000 traps were generated in a 1.3×1.0 square millimeter area!
Particularly cool are the movies in the supplemental information section showing the optoelectronic tweezers in action, examples of which are a B-cell concentrator and an integrated optical manipulator (subscription required to view movies).
The full text, also requiring a subscription, is here.