Large-Scale Culture of 3D Aggregates of Human Pluripotent Stem Cells
Large-scale culture of human pluripotent stem cells (PSCs), including embryonic (ESCs) and induced pluripotent stem cells (iPSCs), will be essential for enabling stem cell therapies, which typically require 108–109 cells/patient. Three-dimensional (3D) cultivation affords higher cell densities and more efficient utilization of medium and factors. Stem cells cultured as aggregates in stirred-suspension bioreactors (SSBs) experience a well-mixed environment that can be monitored and controlled for variables such as dissolved O2 (DO), pH and nutrient concentrations. While human PSCs can be expanded and differentiated in SSBs on microcarriers or after encapsulation, we will focus in this chapter on aspects pertinent to the cultivation of human PSCs as aggregates. These topics include the requirements of human PSC pluripotency and genomic stability, various vessel designs for 3D culture of stem cells, culture parameters, different culture media, and feeding strategies. As the need for stem cell therapeutics intensifies, robust methodologies and technologies for the scalable cultivation of human PSCs will come into sharp focus along with a better understanding of stem cell physiology in the context of bioprocessing.