title: Polarization effects in flow cytometric DNA sizing.
abstract: We have investigated the influence of the polarization direction of excitation light on DNA sizing results obtained by a flow cytometric technique. We found strong fluorescence anisotropy of the fluorescent signal from lambda DNA stained with the bis-intercalating dye TOTO-1. Small fragments of DNA are less sensitive to polarization than larger pieces. This effect is more pronounced at faster flow speeds. These observations show a noticeable orientation of the DNA molecules introduced by the shear forces in the flow system. The data are consistent with an angle between the transition moment of fluorescence of TOTO-1, and the long axis of DNA is approximately 62 degrees .
authors.affiliation: Department of Applied Physics, Applied Optics Group, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Agronskaia
authors.forename: J M
authors.initials: JM
authors.lastname: Schins
authors.forename: B G
authors.initials: BG
authors.lastname: de Grooth
authors.forename: J
authors.initials: J
authors.lastname: Greve