Engineered-Micelles: Alternative to Protein A Chromatography?

We introduce a new concept and a potentially general platform for antibody (Ab) purification that does not rely on chromatography nor specific ligands; rather, it makes use of detergent aggregates capable of efficiently capturing Ab`s while rejecting hydrophilic impurities. Captured Ab`s are then extracted from the aggregates in pure form (>95%) without co-extraction of hydrophobic impurities or aggregate dissolution. The aggregates studied consist of conjugated "Engineered-micelles" built from the nonionic detergent, Tween-20; the hydrophobic metal chelator, bathophenanthroline (batho) and Fe²⁺ ions. When tested in serum-free media with/without BSA (or HSA) as additives, human or mouse IgG’s were recovered at high overall yields (74-80%). Extraction of IgG’s with 7 different buffers at pH 3.8 sheds light on possible interactions between captured Ab`s and their surrounding detergent matrix. Extracted Ab’s preserve their secondary structure, specificity and monomeric character as determined by CD, ELISA and DLS, respectively. Possible integration of the approach within industrial-scale downstream processing of therapeutic grade mAb`s, will be discussed.