| Abstrakt: |
BACKGROUND: Multimodal ion exchangers, containing ligands combining charged and hydrophobic moieties, exhibit enhanced separation compared to monomodal ion exchangers under low loading conditions. Commercial applications often require high protein loads and such conditions have not been investigated extensively, especially for multimodal anion exchangers. This work compares protein adsorption and separation by frontal chromatography for a commercial monomodal (Nuvia HP‐Q) and two multimodal anion exchangers (Nuvia aPrime and Capto Adhere) using bovine serum albumin (BSA) monomer and dimer as a model. RESULTS: Greater dimer–monomer selectivity is observed for Nuvia aPrime and Capto Adhere than for Nuvia HP‐Q at low protein loads. However, binary adsorption isotherms at high protein loads show higher binding capacity and greater selectivity for Nuvia HP‐Q, despite having the same ligand density. Higher salt concentrations reduce the binding strength in all cases, but this reduction is less pronounced for the multimodal resins. As a result, selectivity increases for the latter at higher salt concentrations. Confocal laser scanning microscopy shows that, during co‐adsorption, displacement of the monomer by the dimer occurs for each resin. However, displacement becomes very slow for the multimodal resins during sequential adsorption. The multimodal resins give poorer separation by frontal chromatography, accompanied by low recovery and substantial on‐column formation of protein aggregates. CONCLUSION: The selectivity of multimodal anion exchangers for separation of the model proteins studied varies with salt concentration and protein load. At high protein loads, multimodal resins can result in on‐column aggregate formation negatively impacting the kinetics of competitive binding and separation. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR] |
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