Polyethylene glycol (PEG) is widely used as a surface modification in biotechnology and biopharmaceuticals due to itsthe it’s inert, non-toxic, and water-soluble characteristics. We have conjugated PEG chains to the <i>Staphylococcus aureus</i> Protein A ligands of a commercial affinity chromatography resin to improve its performance in the purification of monoclonal antibodies. Under the expected operating conditions, PEG enthalpic interactions are minimal with other components in the system, allowing the PEG chains to create a steric exclusion barrier around the Protein A ligands. This barrier hinders the binding of undesired species, thus increasing resin selectivity and robustness with minimal sacrifice of antibody binding capacity and affinity. Utilizing Protein A resin monoPEGylated with 20 kDa PEG chains in the purification of monoclonal antibodies from clarified cell culture fluids, we have examined the clearance of host cell proteins, host cell DNA, and monoclonal antibody aggregate species relative to unmodified resin. Impurity levels were observed to decrease compared to the unmodified Protein A control, while minimally reducing monoclonal antibody affinity and capacity. Additionally, through the employment of fluorescently labelled PEG chains, the uniformity of PEGylation across the surface of the chromatography resin beads was analyzed and confirmed using microscopy methods.

PEGylation of protein A chromatography media ligands to exclude contaminants during monoclonal antibody purification

ACS Spring 2022

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