Nonequilibrium transport of rigid macromolecules in periodically constricted geometries.

We consider theoretically the dynamics of short duplex DNA during high-field electrophoresis through a periodic array of narrow slits and deep wells (a nanofilter), where the slit depth is less than the contour length of the essentially rigid DNA strand. In contrast with the known behavior under weak fields, we predict that the larger chains will elute first under strong electric fields via "torque-assisted escape" from the wells. This contradicts the maxim that separations must be performed close to equilibrium, and opens the way for enhanced nanofluidic separations of DNA based upon their out-of-equilibrium transport properties.