(311a) Colloidal Model Applied to Viscosity of Dilute to Semi-Dilute Protein Suspensions

Recently, colloidal models with short range attractive and long range repulsive (SALR) interactions have been applied to biological systems such as protein suspensions. The combination of attractions and repulsions can lead to interesting phase behavior (e.g. gels) and dynamic behavior. In this talk, we focus on dilute to semi-dilute suspensions that are solutions (not gels) but for which the viscosity is not well-modeled by conventional colloidal models. In this range of concentrations, pairwise interactions of the proteins dominate the viscous response. We will show how the coupling of attractions and repulsions can explain some experimental observations of viscosity. This connection is particularly important for therapeutic proteins in which it is desired to have low viscosity at high protein concentration.