Potential of boronic acid functionalized magnetic particles in the adsorption of human antibodies under mammalian cell culture conditions

In this work, we systematically evaluated the potential of using boronic acid functionalized magnetic particles in the capturing of human immunoglobulin G under typical mammalian cell culture conditions. For comparison, Protein A coated magnetic particles were also used. The binding pH was found to significantly influence the adsorption isotherms of boronic acid particles with the higher capacities (0.216 g IgG/g support) being observed at pH 7.4. Comparatively, this value was 0.109 g IgG/g support, for Protein A particles under the same conditions. Both particles revealed very fast adsorption kinetics with more than 70% of the maximum binding capacity being achieved in a few seconds. The effect of glucose and lactate, which are known to interact with boronic acid, was evaluated. For glucose, the binding capacity was significantly influenced by the pH and decreased as pH increased. At pH 9.5, a 70% lower binding capacity was observed for glucose concentrations as low as 0.5 g/l. The effect of lactate was less pronounced and almost pH independent reaching at most 20% decrease in binding capacity. Nevertheless, the effect of both molecules was always lower at pH 7.4. The optimization of the elution conditions enabled complete recovery of bound IgG from boronic acid particles using 50 mM Tris–HCl, 200 mM sorbitol, 200 mM NaCl at pH 8.5.