Optical Trapping and Manipulation of Viruses and Bacteria.

Optical trapping and manipulation of tobacco-mosaic viruses and motile bacteria by the radiation pressure forces of laser light were demonstrated using single-beam gradient traps. Individual viruses and dense oriented arrays of viruses were trapped in aqueous solution with no apparent damage using ~120mW of argon laser power. Trapping and manipulation of single live bacteria and collections of bacteria were also demonstrated in a high resolution microscope at powers of a few milliwatts. It is suggested that these new capabilities based on use of traps as so-called optical tweezers for confining and manipulating particles will find applications in the biological sciences.