Pluripotent stem cells have great potential for use in regenerative medicine and are an important tool for understanding developmental and disease mechanisms. Unfortunately, properly characterizing these cells in order to maintain experimental consistency is proving to be a time-consuming and difficult task. The defining characteristics of pluripotent stem cells, which include embryonic stem (ES) cells and induced pluripotent stem (iPS) cells, are straightforward: their ability to self-renew and differentiate into ectoderm, mesoderm, and endoderm germ layers. What makes characterization challenging is that heterogeneity within a given stem cell population can cause variability in the differentiation into important downstream lineages, such as cardiomyocytes and hepatocytes.
To account for this high level of functional variation, verifying the pluripotency of stem cells—from the generation of a new cell line through its expansion for an experiment—is crucial. The most widely accepted method for determining whether a population of cells is truly pluripotent is the teratoma assay, that is, verifying in vivo a cell population’s ability to differentiate into each of the three germ layers via teratoma formation in mice. This method is time-consuming and costly, but failing to properly verify the cells can prove even more costly. Time and resources spent expanding stem cells are wasted if the resulting population is not functionally pluripotent. To address these difficulties, R&D Systems has developed new tools that aid in the verification of stem cell pluripotency during derivation, maintenance, and expansion.