(365d) Saturation of the Cross-Stream Migration of DNA Driven by a Pressure Gradient and An Electric Field

DNA exhibits a transverse migration across streamlines under
simultaneous electrophoresis and pressure-driven flow.  We have
proposed that the migration is driven by long-range hydrodynamic
interactions generated by the electric field acting upon the
polyelectrolyte, which is distorted from its equilibrium conformation
by the local shear.  A coarse-grained simulation that includes the
hydrodynamic interactions from the imposed flow and electric fields
captures the observed migration of DNA molecules.  This model also
predicts that the extent of migration saturates at a high field
strength when holding the flow rate constant.  Measurements of DNA in
a microfluidic channel confirm that this saturation, previously
unobserved, does exist. This finding provides additional evidence in
support of the model and the concept that hydrodynamic interactions
generated by an electric field acting on a polyelectrolyte are not
fully screened.