The multiparametric effects of hydrodynamic environments on stem cell culture.

Stem cells possess the unique capacity to differentiate into many clinically relevant somatic cell types, making them a promising cell source for tissue engineering applications and regenerative medicine therapies. However, in order for the therapeutic promise of stem cells to be fully realized, scalable approaches to efficiently direct differentiation must be developed. Traditionally, suspension culture systems are employed for the scale-up manufacturing of biologics via bioprocessing systems that heavily rely upon various types of bioreactors. However, in contrast to conventional bench-scale static cultures, large-scale suspension cultures impart complex hydrodynamic forces on cells and aggregates due to fluid mixing conditions. Stem cells are exquisitely sensitive to environmental perturbations, thus motivating the need for a more systematic understanding of the effects of hydrodynamic environments on stem cell expansion and differentiation. This article discusses the interdependent relationships between stem cell aggregation, metabolism, and phenotype in the context of hydrodynamic culture environments. Ultimately, an improved understanding of the multifactorial response of stem cells to mixed culture conditions will enable the design of bioreactors and bioprocessing systems for scalable directed differentiation approaches.