A single-cluster light scattering study of fast-aggregating protein-coated polymer colloids

Abstract

We show how single-cluster light scattering may be used to study the aggregation kinetics of surface-modified colloidal particles. The surface characteristics of the particles were modified by adsorbing different amounts of bovine serum albumin (BSA). All aggregation measurements were performed at high salt concentration and at the protein’s isoelectric point. Single-cluster light scattering was employed to determine how different amounts of BSA adhered on the particle surface affect the aggregation mechanism. The results obtained show that the cluster size distributions scale independently of the degree of surface coverage. It was found that the BSA molecules drastically change the time evolution of the number-average cluster size. Nevertheless, the homogeneity parameter remains practically zero at all degrees of surface coverage and, hence, the aggregation regime is diffusion-like.