Cornell Researchers Use Light to Trap and Move DNA Molecules

David Ericson and Michal Lipson of Cornell University (Ithaca, New York) have a designed an optofluidic system that uses the pressure of light to move and manipulate biological molecules. A new slot waveguide device created by Lipson that consisted of two parallel silicon bars spaced 60 nm apart served as two parallel waveguides and allowed a beam of light to be channeled through air or water. By placing the slot waveguide across a microscopic fluid channel, they were able to use infrared laser light to trap 75-nm polystyrene spheres and similarly sized DNA molecules from a stream of water flowing across it. According to the researchers, the device has the potential to separate biological molecules out of a stream and send them elsewhere for processing and possibly separate DNA molecules by length for sequencing.