Figure 3.
Effect of molecular crowding and excluded volume on microscale-volume viscosity. (a) The excluded volume comprises the space occupied by molecules (green) and the depletion layer surrounding them (gray). (b) Within a crowded solution, two molecules cannot occupy the same space, but their depletion layers can overlap. (c) The viscosity within the depletion layer (ηdl) surrounding a particle is between the pure-buffer (solvent system) viscosity (ηs) and the experimentally measured macroscopic viscosity (ηmacro).108