Polarization effects in flow cytometric DNA sizing.
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 .
Agronskaia
A
A
Department of Applied Physics, Applied Optics Group, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Schins
J M
JM
de Grooth
B G
BG
Greve
J
J