Characterization of a ceramic monolithic support for affinity protein chromatogrophy

Affinity chromatography is a process for the separation of biomolecules from complex mixtures. Its versatility, high selectivity and efficiency make it the most currently used method in the final stages of purification of pharmaceutical and food industries, where a high degree of purity is required. Conventional affinity chromatography uses packed beads as solid support and suffers of several limitations, such as high material costs, high operating costs, intraparticle diffusion as primary transport phenomenon and difficulties in column packing. Therefore, it is necessary to develop and characterize cheaper and more efficient materials as stationary phase for chromatographic separations. From this perspective, monolithic media have shown a significant potential. In this research project a new ceramic composite monolithic support, a cellular Al2TiO5 and Al2TiO5-Al2O3 composite monolith, has been experimentally characterized. First, several monolithic columns have been prepared, by polishing the material to obtain cylindrical samples of the desired height and dimensions. Then the columns have been characterized by calculating the main fluid dynamic parameters that govern the motion of a fluid in a porous material: permeability, porosity and axial dispersion coefficient. To this aim permeability tests and pulse tests have been performed. One column has been functionalized with epoxy groups, by linking 3-glycidoxypropyltrimethoxysilane (GPTMS). This step, called activation, creates active sites for the immobilization on the support of protein A, that on turn is used for the affinity adsorption of immunoglobulin-G. The number of active epoxy groups has been estimated by measuring the ability of the column to irreversibly bind the bovine serum albumin, BSA, in chromatographic experiments.