Current Developments in the Stable Production of Human Induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) are considered to be ideal and promising cell sources for various applications such as regenerative medicine and drug screening. However, effective mass production systems for the stable supply of desired numbers of iPSCs are yet to be developed. This review introduces the various approaches that are currently available for stable iPSC production. We start by discussing the limiting factors to be controlled during iPSC culture, such as nutrient supply, waste removal, and oxygen availability. We then introduce recent investigations on iPSC culture systems based on adhesion, suspension, and scaffolds. We also discuss the downstream processes that follow the culture process, such as filling and freezing processes, which limit the production scale due to decreased cell viability during suspension in cryopreservation medium. Finally, we summarize the possibility of the stable mass production of iPSCs and highlight the limitations that remain to be overcome. We suggest that multidisciplinary investigations are essential to understand the different factors that influence cell growth and quality in order to obtain an optimal and stable iPSC mass production system. (C) 2021 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company.