Complex effects of molecular topology on diffusion in entangled biopolymer blends

By combining single-molecule tracking with bond-fluctuation model simulations, we show that diffusion is intricately linked to molecular topology in blends of entangled linear and ring biopolymers, namely DNA. Most notably, we find a previously unreported non-monotonic dependence of the self-diffusion coefficient for linear DNA on the fraction of linear DNA comprising the ring-linear blend, which we argue arises from a second-order effect of ring DNA molecules being threaded by varying numbers of linear DNA molecules. Results address several debated issues regarding molecular dynamics in biopolymer blends, which can be used to develop novel tunable biomaterials.