The dynamical behavior of the neutral polymer (dextran, $M_w=2\mathrm{}\times {10}^6)$ is investigated during DNA electrophoresis in a dilute solution. Using a fluorescence recovery after photobleaching setup, we measured the velocity of fluorescein-labeled dextran induced by the migration of the DNA. We found that each DNA molecule drags a large number of dextrans with it. We show that DNA-dextran interactions are not only binary but long range and indirect. We conclude that the DNA-dextran complex creates a hydrodynamic field that entrains polymers far from the DNA during electrophoresis.

• Received 7 November 2002

DOI:https://doi.org/10.1103/PhysRevE.67.051920