Green solvent-based highly permeable PES membranes for virus filtration in bioprocesses

초록

In the downstream processing of mammalian cell-based biotherapeutics, virus filters play an indispensable role in ensuring product purity and viral safety. As only a few commercial filters have dominated the virus filtration market for decades, there is strong demand for alternative or new virus filters with high flux, throughput, and removal efficiency, in line with market growth and advances in biotechnology. This study focuses on the development of a highly permeable virus filtration membrane with a bi-continuous pore structure, fabricated using a green solvent (gamma-butyrolactone) based phase separation process. The optimal composition of the green solvent-based dope solution was determined using Hansen solubility parameter analysis, enabling the formation of a macrovoid-free, sponge-like structure essential for effective virus capture. Membrane fabrication was carried out using pilot-scale roll-to-roll equipment under controlled environmental conditions to minimize defects and performance variability. A comprehensive study involving membrane preparation, characterization, and virus challenge testing was conducted to validate the membrane's exceptional permeability and virus removal efficiency. The optimized polyether sulfone (PES) virus filters demonstrated a narrow pore size distribution, high virus removal capacity (>7 log reduction value, LRV), and outstanding permeation flux (900 LMH/bar for a single layer and 450 LMH/bar for bi-layers), which is 2-20 times higher than that of commercial virus filters. The results indicate that these high-throughput virus filters can significantly reduce virus filtration costs and processing times.

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