Expansion and characterization of mesenchymal stem cells and other anchorage-dependent cell types in fluoropolymer bags treated for adherent cell culture

Abstract

Background & Aim Modern cell based therapies continue to gain momentum as demonstrated by the growing number of clinical trials and cell therapy commercialization centers. A growing shift towards closed manufacturing systems to replace conventional functionally open systems such as tissue culture polystyrene (TCPS) flasks has prompted the development of various oxygen-permeable cell culture bags made from materials such as fluorinated ethylene propylene (FEP). However, hydrophobic materials such as untreated TCPS or FEP do not support adequately the growth of anchorage-dependent cells. For this reason, most TCPS vessels sold for adherent culture undergo plasma or liquid based surface treatments which increase surface wettability and cell adhesion. Unlike TCPS, the effect of FEP vessels treated for adherent culture on cell adhesion is poorly documented. This is a major obstacle for the production of anchorage-dependent cell based therapies in a closed setting. The objective of this study was to investigate the impact of the treated form of FEP on adherent cell cultures. Methods, Results & Conclusion Different types of anchorage-dependent cells, including mesenchymal stem cells (MSCs), mouse insulinoma 6 (MIN6) cells and human embryonic kidney (HEK) cells, were cultured in treated-FEP (VueLife® AC Series) bags and their biological properties were analyzed in comparison to cells seeded on untreated-FEP (VueLife® C Series) and/or treated-TCPS (Nunclon™ Delta-treated T-flasks). Light microscopy revealed that surface treatment enhanced adhesion on FEP, but final adherent cell yields after expansion remained lower than on treated-TCPS. Additionally, we observed that surface treatment of FEP did not affect the differentiation status of expanded MSCs or MIN6 populations. As expected, the removal of proteins from the medium or integrin inhibition reduced cell adhesion. Overall, our results demonstrate that a wide range of anchorage-dependent cells, including primary cells (MSCs) and immortalized cell lines (anchorage-dependent HEK cells, MIN6) can be successfully expanded in VueLife® AC bags. As an increasing number of adhesion cell based therapies are ready to enter the clinic, there is a pressing need to find the appropriate cell culture vessels and materials for better clinical outcomes.