Fractal aggregates induced by antigen-antibody interaction

We report measurements on the aggregation processes in a colloidal suspensi on of polystyrene particles covered with F(ab')(2) (immunoglobulin IgG frag ment) in the presence of CRP antigen (C-reactive protein) performed by stat ic and dynamic light scattering. To study the cluster morphology of aggrega tes, the fractal dimension is obtained from the dependence of the scattered intensity on the scattering wavenumber. The fractal dimension values so de termined were higher than those predicted by irreversible aggregation simul ation models and then closer to those obtained by reversible clustering mod els.