Evaluation and Prediction of Protein Binding to Multi-Modal Anion Exchange Chromatographic Systems

While recent advances in multi-modal chromatography have shown significant potential for protein purification, there is a significant need to establish a deeper understanding of the nature of selectivity in these systems. In this paper, a set of proteins with a wide range of physicochemical properties (e.g. size, shape, surface area, charge and hydrophobicity) was employed to investigate affinity and selectivity in multimodal chromatographic systems. Batch and column experiments were carried out under a range of mobile phase conditions (e.g. pH, salt, mobile phase modifiers) to determine selectivity trends and to identify unique binding behavior. The selectivities achieved with these multi-modal materials were then compared to those obtained with traditional IEX and HIC chromatographic systems, Finally, quantitative structure property relationship (QSPR) models were developed using novel molecular descriptors developed for multimodal ligands to predict the binding affinity of proteins to multi-modal resins under a wide range of conditions. The fundamental insights from this work will improve our understanding of the binding mechanisms in multimodal chromatography and will facilitate the prediction of retention behavior in multi-modal chromatographic systems.