Cellulose-<i>graft</i>-polyethyleneamidoamine Anion-Exchange Nanofiber Membranes for Simultaneous Protein Adsorption and Virus Filtration

Abstract

Development of bioseparation media that can perform separations based on both ion exchange and size exclusion provide a transformative technology to purify therapeutic proteins with fewer operations in downstream processing. Thus, in this study, we have developed cellulose-graft-polyethyleneamidoamine (CL-g-PEAA) anion-exchange nanofiber membrane adsorbers with a narrow effective pore size distribution using redox polymerization. Structural characterization illustrated the functionalization of each nanofiber of the CL-g-PEAA membrane adsorbers with three-dimensional nanolayers of amidoamine functionality. The ion-exchange separation efficiency of the CL-g-PEAA anion-exchange membranes, evaluated using bovine serum albumin (BSA), exhibited an excellent static adsorption of 239 mg/g of nanofibers. The BSA dynamic binding capacity in flow through mode at 10% breakthrough of these membranes was 69 mg/g (corresponding to a volume capacity of 31 g/L) with an approximate residence time of 8 s. Meanwhile, CL-g-PEAA membranes have shown 80–100% rejection for model bead particles of various sizes (200, 100, and 40 nm), which illustrated the potential in removing viruses, microbial agents, and cellular debris from the harvested cell culture fluid (HCCF) during downstream processing. Overall performance of the CL-g-PEAA membranes illustrated that undesired impurities (viruses, host cell proteins, and DNA) in HCCF could be removed in a single step by an anion-exchange membranes with ion-exchange and size-exclusion-based separation mechanisms.