Manipulation of single coiled DNA molecules by laser clustering of microparticles

Abstract
We have developed a method of manipulating single DNA molecules for application in single-molecule analysis. Using a bead cluster formed by laser trapping, the technique allows single DNA molecules to be manipulated at any point on the molecule without the need for prior chemical modification as in DNA-bead complex techniques. We describe the method and the characteristics of cluster formation, and present examples of actual DNA molecule manipulation.