Giant Acceleration of DNA Diffusion in an Array of Entropic Barriers*

We investigate with experiments and computer simulations the non-equilibrium dynamics of DNA polymers crossing arrays of entropic barriers in nanofluidic devices in a pressure-driven flow. With increasing driving pressure, the effective diffusivity of DNA rises and then peaks at a value that is many times higher than the equilibrium diffusivity. This is an entropic manifestation of "giant acceleration of diffusion", a non-equilibrium dynamical phenomenon for which an analytical solution is available. The phenomenon is sensitive to the effective energy landscape, thus it offers a unique probe of entropic barriers in a system driven away from equilibrium.