(411e) Cross-Stream Migration of Polyelectrolytes Driven by a Pressure Gradient and An Electric Field

In dilute salt concentrations, DNA exhibits a transverse migration in the presence of a combined electric and pressure-driven-flow fields [1]. We propose that long-range hydrodynamic interactions generated by the electric field cause migration of a polyelectrolyte that is distorted from its equi- librium conformation by the local shear [2]. Moreover, we predict swelling of the polyelectrolyte at high electric fields due to internal dispersion, which significantly alters the migration profile. I describe a coarse-grained simulation of polyelectrolyte migration that includes hydrodynamic in- teractions from the imposed flow and electric fields. The model captures the observed migration of DNA molecules towards the center of the channel when the electric field and pressure gradient are concurrent and the migration towards the boundaries when the applied fields are in opposition. Results from simulations are compared with the experimentally observed migration profiles for various combinations of flow and electric field. [1] Zheng J.J. and Yeung E.S., Aust. J. Chem. 56, 149 (2003). [2] Butler J.E., Usta O.B., Kekre R. and Ladd A.J.C., Phys. Fluids 19, 113101 (pages 14)(2007).