Progress and challenges in large-scale expansion of human pluripotent stem cells

The constant supply of high cell numbers generated by defined, robust, and economically viable culture processes is indispensable for the envisioned application of human pluripotent stem cells (hPSCs) and their progenies for drug discovery and regenerative medicine. To achieve required cell numbers and to reduce process-related risks such as cell transformation, relative short batch-like production processes at industry- and clinically-relevant scale(s) must be developed and optimized. Here, we will review recent progress in the large-scale expansion of hPSCs with particular focus on suspension culture, which represents a universal strategy for controlled mass cell production. Another focus of the paper relates to bioreactor-based approaches, including technical aspects of bioreactor technologies and operation modes. Lastly, we will discuss current challenges of hPSC process engineering for enabling the transition from early stage process development to fully optimized hPSC production scale operation, a mandatory step for hPSCs’ industrial and clinical translation.