Complex diffusion in biopolymer networks with added molecular crowding

Intra- and extracellular diffusion can depend sensitively on the environmental details. In general the diffusion is hindered and can be subdiffusive, varying heterogeneously due to molecular crowding and interactions with an immobile polymer network. We study the combined effects of polymer-hindrance and molecular crowding using particle tracking and correlation analyses applied to microspheres diffusing in Type I collagen with added polyethylene glycol.