ABSTRACT
Acknowledgments ...................................................................................................................... 310 References .................................................................................................................................. 311
Flocculation and stability of protein-functionalized colloidal particles play an important role especially in life sciences. Examples thereof are immunoassays, where antibodies act as occulating agents for antigen-covered particles and vice versa [1], and aggregation of micelles that may contain in their membranes different proteins of biological interest [2,3]. Even when these functionalized particles are dispersed in physiological uid, they may aggregate due to the formation of protein “bridges” [4]. Since other aggregation mechanisms, such as electrolyte-induced coagulation or weak occulation, may also take place, cluster formation becomes the result of the interplay of these effects. It is, however, still not completely clear how the different experimental conditions affect the aggregation mechanisms and the structure of the resulting clusters. Hence, occulation of protein-functionalized particles is a highly complex process that shows some analogies with what is known as “bridging occulation” [5,6]. Nevertheless, it cannot be classi ed as such in a stricter sense. Moreover, pure
bridging occulation is not as thoroughly understood as electrolyte-induced coagulation and there are still several aspects that are of indubitable interest for modern research such as the aggregation kinetics [7,8], the in uence of the occulating agent’s nature [9,10], the structure of the aggregates formed [11,12], and the forces that lead to polymer adsorption and their nal conformation [13]. For this reason, we focus our attention on the kinetic aspects of the occulation process and the structural properties of the clusters formed. Both aspects, aggregation kinetics and cluster morphology, are mainly a consequence of the interplay between particle diffusion and interparticle interaction. As several authors have stated, very little work has been reported on this subject so far [8-11].
