Partial hydrodynamic screening of confined linear and circular double-stranded DNA dynamics.

We performed experiments and simulations to investigate the influence of hydrodynamic interaction on the diffusion dynamics of circular and linear λ-DNA confined in nanoslits. Contrary to the common assumption that intrachain hydrodynamic interaction (HI) is completely screened when polymers are confined in channels with height h smaller than the radius of gyration R(g), it is found that the HI is partially screened and approaches complete screening only for R(g)≪h. For λ-DNA, the HI becomes nearly completely screened only when the channel height is smaller than the Kuhn length. In addition, the dynamics of linear and circular λ-DNA in very strong confinement is shown to be independent of the chain topology.