Long-term perfusion processes are increasingly used to intensify upstream operations, but robust implementation at large scale remains challenging. Alternating tangential flow filtration (ATF) has been the primary choice for cell retention due to its perceived ease of scalability. However, at manufacturing scale ATF can limit process performance due to filtration constraints, limited flexibility for further optimization, and high cost. In addition, our single-use upstream (USP) platform requires single-use cell retention devices that can be seamlessly connected to single-use bioreactors, while supporting harvest targets of up to 4000 L per day from a 2000 L perfusion bioreactor.

Our objective was to identify and characterize scalable, single-use–compatible, and cost-effective alternatives to ATF for cell retention in perfusion processes. We evaluated high-performance tangential flow filtration (HPTFF) and reverse tangential flow filtration (rTFF) across multiple scales. HPTFF was tested at 3.5–25 L working volume, while rTFF was assessed from 3.5 L up to 200 L. Performance was characterized in terms of cell retention efficiency, filtration behavior, ability to reach the required harvest rates, and impact on perfusion stability, product quantity, and product quality. In collaboration with Levitronix®, we developed an rTFF cart at 200 L scale and operated it over several days to evaluate long-term robustness under intensified perfusion conditions.

Our results highlight the key opportunities and remaining challenges associated with HPTFF and rTFF as single-use–compatible alternatives to ATF.