Media and microcarrier surface must be optimized when transitioning mesenchymal stem/stromal cell expansion to stirred tank bioreactors

Background The long-term outlook for regenerative medicine predicts an increased need for high quality materials that are compatible with the limited number of downstream processing steps required for cell-based therapies. Large scale manufacturing of adherent-dependent cell types necessitates movement away from planar culture and toward technologies such as stirred tank bioreactors where suspension culture using microcarriers is enabled [1]. Microcarriers are available in a variety of base materials including glass, polystyrene or dextran, and have been coated or derivatized to carry charge, peptides or extracellular matrix proteins such as collagen that may be animal-derived. Cell culture medium may also contain animal-derived components. Fetal bovine serum (FBS) in particular is associated with regulatory, supply, and consistency challenges [2]. Eliminating this commonly-used reagent will require thorough evaluation of animal originfree materials for compatibility with cell therapy applications. Here, we evaluated growth of human mesenchymal stem/stromal cells (MSCs) with a variety of microcarriers and cell culture media formulations. Not only was a wide range of performance observed between the microcarriers and media screened, but positive performance in static culture was not necessarily predictive of that under agitated conditions.