Hybrid magnetic systems for the purification of biopharmaceuticals

Monoclonal antibodies are used as therapeutic agents worldwide and have a great market demand. However, the downstream processing of these biopharmaceuticals represents between 50-80% of the total manufacturing costs and therefore new methods which are less expensive but also efficient are needed. The aim of this work was to develop a non-chromatographic method for the purification of antibodies from cell culture supernatants by process integration of two methods, namely aqueous two-phase extraction (ATPE) and magnetic fishing. The behavior of a new aqueous two-phase systems (ATPS) was investigated by varying the NaCl concentration and the molecular weight of a polymer. This study allowed to select the composition of the systems that would be used in the study of the partition of bovine serum albumin (BSA) used as a model contaminant and immunoglobulin G (IgG). Simultaneously, magnetic particles (MNPs) with 2 different coatings were synthesized and assessed for protein binding. One of the particles was selected due to the easier synthesis and the high affinity and selectivity towards human IgG. Furthermore, one system was chosen as the most suitable magnetic aqueous two phase fishing system (MATPFS) to recover IgG. The control studies, which consisted of using separately the ATPE and magnetic fishing to purify IgG from a cell culture supernatant, presented low values of yield and purity when compared with the results obtained by combining these two methods