Interesting article using laser beams to sort DNA molecules.

Scientists create a 'tractor beam'
Source: UPI

OAK RIDGE, Tenn. (UPI) -- Oak Ridge, Tenn., scientists are using a beam of light, similar to "Star Trek's" tractor beams, to trap protein molecules and make them dance in space.

The technique -- developed by scientists from the Department of Energy's Oak Ridge National Laboratory, the California Institute of Technology and a company called Protein Discovery -- is said to be useful for separating, concentrating and analyzing proteins quickly, with high sensitivity and selectivity.

"With this technique, we can steer DNA or other biomolecules for transport in three dimensions and also separate them according to size and their isoelectric point," said Chuck Witkowski, a co-author and president of Protein Discovery, a Knoxville startup company.

The isoelectric point is the point at which a molecule carries no net electrical charge.

The technique -- called photoelectrophoretic localization and transport -- involves shining a highly focused beam of light on semiconductor material and using electric fields to move the proteins. Force-field traps are created by a photocurrent focused at the illuminated areas of the semiconductor.

"It's kind of like a tractor beam in 'Star Trek,' but this is science, not science fiction," said Nathan Lewis, a Caltech professor and co-author of the study.

The research appears in the Proceedings of the National Academy of Sciences Early Edition.
Copyright 2006 by United Press International