Optimization of silica-based media for antibody purification by protein A affinity chromatography.

Considering the large molecular size of IgG antibodies widely used for therapeutic applications, the pore size, pore volume and coupling density of silica-based media were optimized for the effective large-scale purification, using an antibody-protein A affinity system. Silica media, with average pore sizes from 70 nm to 140 nm and surface areas of 26-67 m(2)/g, were prepared and coupled with protein A. The static adsorption capacity and dynamic binding capacity of bovine and human IgG were measured at superficial liquid velocities ranging from 94 to 720 cm/h. The volumetric coefficient of mass transfer of the alkali-treated silica-based protein A media, with a pore size of 110 nm, was four times higher than the values for cross-linked agarose media and thus had high dynamic binding capacities at high superficial liquid velocities.