Light-Scattering Studies of Aggregation [and Discussion]

We discuss dynamic and static light-scattering measurements made during slow (reaction-limited) aggregation of model colloids and immune complex forming proteins. Analysis of the results leads to an understanding of the random aggregates formed in terms of a fractal geometry and measurement of the fractal dimension. Differences in the measured fractal dimensions of the model and protein systems are discussed. The aggregation appears to follow 'Smoluchowski-like' kinetics as measured by a near linear growth of the low-angle light scattering with time. However, the dynamic light-scattering results support a simple power-law model for the aggregate distribution and allow an estimate of this power law to be made.