This research employs chromatographic studies with and ligand and protein libraries to provide insights into the design of novel chromatographic systems.
High throughput and bench top chromatography are employed to study the retention behavior of various separation systems and separation problems. NMR and covalent labelling/enzymatic digest/mass spectrometry are used to determine preferred binding domains of proteins interacting with various chromatographic surfaces.
Nuclear Magnetic Resonance (NMR) is widely employed for protein structure determination and measuring protein-target interactions. In our studies, two dimensional heteronuclear single quantum correlation (HSQC) experiments are employed to study the interactions of proteins with ion exchange and multimodal (MM) chromatographic ligands in solution.
During the production of IgG-like bispecific antibodies numerous product related impurities are formed. These impurities have similar surface properties to the desired product. As a consequence, single mode chromatography lacks the selectivity required to achieve both high yield and high purity of the product bsAb. Mixed mode chromatography has demonstrated improved selectivity relative to single mode resins like IEX and HIC.
Orthogonal separation by chromatography is crucial to an effective downstream purification process for biotherapeutics. Heuristically, chromatographic steps that employ different modalities of interaction, such as ion exchange (IEX) or hydrophobic interaction (HIC), are believed to be orthogonal. However, the degree of orthogonal separation is seldom quantified, which may overlook opportunities for synergistic separation across different chromatographic resin pairs or sequences.
We are developing novel multimodal ligand libraries in order to better understand the relationship between ligand chemistry and preferred chromatographic behaviors such as separability and peak shape. These ligands are based on small molecule and short peptide frameworks. These ligands are synthesized and evaluated, the results of which are used to inspire the generation of future, enriched libraries.