Magnetic aqueous two phase fishing: a hybrid process technology for antibody purification

The potential to combine aqueous two-phase extraction (ATPE) with magnetic separation was here investigated with the aim of developing a selective non-chromatographic method for the purification of antibodies from cell culture supernatants. Aqueous two-phase systems (ATPS) composed of polyethylene glycol (PEG) and dextran were supplemented with several surface modified magnetic particles (MPs) at distinct salt concentrations. The partition of pure human IgG in the upper and lower phases as well as the amount adsorbed at the MPs surface was investigated, indicating that MPs coated with dextran and gum Arabic established the lowest amount of non-specific interactions. The binding capacity of gum arabic coated particles modified with aminophenyl boronic acid (GA-APBA-MP) was were found to be excellent in combination with the ATPS system, yielding high yields of antibody recovery (92%) and purity (98%) from cell culture supernatants. The presence of MPs in the ATPS was found to speed up phase separation (from 40 to 25min), to consume a lower amount of MPs (half of the amount needed in magnetic fishing) and to increase the yield and purity of a mAb purified from a cell culture supernatant, when compared with ATPE or magnetic fishing processes alone.