A novel filtration system for point of care washing of cellular therapy products

Abstract

The cell therapy industry would greatly benefit from a simple point of care solution to remove dimethylsulphoxide (DMSO) from small-volume thawed cell suspensions before injection. A novel dead-end filtration device has been designed and validated, which takes advantage of the higher density of thawed cell suspensions to remove the DMSO and protein impurities from the cell suspension without fouling the filter membrane. The filter was designed to avoid fluid circuits and minimize the surface area that is contacted by the cell suspension, thus reducing cell losses by design. The filtration process was established through optimization of the fluid flow configuration, backflush cycles and filter geometry. Overall, this novel filtration device allows for a 1 ml of thawed cryopreserved cell suspensions, containing 10 cells of a fetal lung fibroblast cell line (MRC-5), to be washed in less than 30 min. More than 95% of the DMSO and up to 94% of the albumin-fluorescein-isothiocyanate content can be removed while the viable cell recovery is higher than 80%. It is also demonstrated that this system can be used for bone marrow-derived human mesenchymal stem cells with more than 73% cell recovery and 85% DMSO reduction. This is the first time that a dead end (normal) filtration process has been used to successfully wash high-density human cell suspensions. In practice, this novel solid-liquid separation technology fills the need for small-volume washing in closed processing systems for cellular therapies. Copyright © 2016 John Wiley & Sons, Ltd.

Dimethyl Sulfoxide: A Central Player Since the Dawn of Cryobiology, is Efficacy Balanced by Toxicity?

“…Recently, Tostoes et al demonstrated the use of a novel filtration system for the removal of DMSO from cryopreserved small volume samples, containing 10 7 fetal lung fibroblasts or bone marrow MSCs [158]. The system resulted in the elimination of 85-95% of DMSO with more than 70% cell recovery.…”

Technical Considerations in the Freezing, Low-Temperature Storage and Thawing of Stem Cells for Cellular Therapies

“…However, these systems, based on continuous centrifugation or tangential flow filtration, are only suited to concentrating cells from large volumes upstream of the cryopreservation process. Automated washing system for removal of CPA and cellular debris have been described recently [75] but are not yet commercially available (www.closedcellsystems.com).…”