Product sieving of mAb and its high molecular weight species in different modes of ATF and TFF perfusion cell cultures

Abstract

BACKGROUND: Tangential flow filtration (TFF) systems are widely used cell retention devices in perfusion cultures, but significant challenges occur with their prolonged operation. A well-known and common issue includes membrane fouling, which leads to reduced permeate flow and increased product retention. The fouling behavior in hollow fibers have been studied widely and the application of alternating flow profiles, cell lysis, shear stress, and membrane pore size have been found to be major contributors to this phenomenon. RESULTS: In this work, different process set ups and conditions were tested using magnetic levitation pumps for low shear TFF systems in small-scale perfusion bioreactors (200 mL). A novel concept based on the application of reverse flow across the hollow fiber using two magnetically levitating pumps was validated with a Chinese Hamster Ovary cells (CHO) cell line producing a recombinant monoclonal antibody. Product sieving could be improved by 30% when a dynamic recirculation flow was applied. Furthermore, minimal product retention was achieved by reversing the flow of two alternating pumps with short cycle times. Besides this, a correlation was found between the passage of high molecular weight species to the harvest stream of the perfusion process and the flow direction, as well as the degree of product sieving. CONCLUSION: TFF with a reverse flow is a valuable alternative to an alternating tangential flow (ATF) system for overcoming antibody retention and it can be used at various scales and at a constant bioreactor volume. The comparison of ATF and TFF showed differences in product yield and purity and is, therefore, an important point for process design. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).