Abstract
Human pluripotent stem cells (PSCs) provide an unlimited cell source for cell therapies and disease modeling. Despite their enormous power, technical aspects have hampered reproducibility. Here, we describe a modification of PSC workflows that eliminates a major variable for nearly all PSC experiments: the quality and quantity of the PSC starting material. Most labs continually passage PSCs and use small quantities after expansion, but the "just-in-time" nature of these experiments means that quality control rarely happens before use. Lack of quality control could compromise PSC quality, sterility, and genetic integrity, which creates a variable that might affect results. This method, called CryoPause, banks PSCs as single-use, cryopreserved vials that can be thawed and immediately used in experiments. Each CryoPause bank provides a consistent source of PSCs that can be pre-validated before use to reduce the possibility that high levels of spontaneous differentiation, contamination, or genetic integrity will compromise an experiment.