Diffusion of a single semiflexible charged polymer

The diffusion of charged semiflexible polymers is studied by hydrodynamic simulations. The salt-dependent diffusion constant exhibits a shallow minimum at a screening length comparable to the polymer length. Fluorescence correlation spectroscopy data for 394 bp ds-DNA fragments confirm the relative insensitivity of diffusion over a wide range of salt concentrations. A scaling expression for the diffusion constant of a neutral semiflexible chain encompassing the rod, the intermediate ideal and the asymptotic swollen regime is constructed.