Extracellular Vesicle Collection from Human Stem Cells Grown in Suspension Bioreactors.

Extracellular vesicles (EVs) are particles with 100-1000 nm sizes which are secreted by cells for intercellular communication. Meanwhile, studies have found that EVs secreted by human stem cells carry similar characteristics (microRNAs, proteins, metabolites, etc.) from their cell counterpart. Thus, EVs derived from stem cells, especially human induced pluripotent stem cells (hiPSCs) and human mesenchymal stromal/stem cells (hMSCs) are promising candidates for cell-free therapy. However, conventional planar culture is insufficient to produce a large amount of cells or EVs to satisfy clinical requirements. In this chapter, we described feasible approaches to harvest EVs secreted by lineage-specific hiPSCs and undifferentiated hMSCs in suspension bioreactors. Differentiation of hiPSCs to cortical organoids can be performed in suspension bioreactors and the corresponding EVs can be isolated and purified. This scale-up protocol can be applied to a majority of stem cell types with EV collection thus provides useful information for both experimental and biomanufacturing purposes.