title: Extension of a DNA molecule by local heating with a laser.
abstract: Thermal convection and thermophoresis induced by mum-scale local heating are shown to elongate a single DNA molecule. An infrared laser used as a point heat source is converged into a dispersion solution of DNA molecules, which is observed under a fluorescent microscope. The thermal convection around the laser focus manifests as extensional flow for the long DNA chain. A simulation of thermal convection that reproduces the experimental condition provides numerical support for the stretching caused by thermal convection. This DNA elongation technique is a novel method for manipulating the intact single DNA molecules, and it can be applied to a "lab on a chip".
authors.affiliation: Department of Physics, Graduate School of Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kimura
mesh_terms: D004247:DNA / Q000737:chemistry*; D006361:Heating; D007834:Lasers; D008846:Micromanipulation / Q000379:methods*
chemical_list: D004247:DNA