Human embryonic stem cells (hESCs) are pluripotent cells derived from the embryo at the blastocyst stage. Their embryonic origin confers upon them the capacity to proliferate indefinitely in vitro while maintaining the capacity to differentiate into a large variety of cell types. Based on these properties of self-renewal and pluripotency, hESCs represent a unique source to generate a large quantity of certain specialized cell types with clinical interest for transplantation-based therapy. However, hESCs are usually grown in culture conditions using fetal bovine serum and mouse embryonic fibroblasts, two components that are not compatible with clinical applications. Consequently, the possibility to expand hESCs in serum-free and in feeder-free culture conditions is becoming a major challenge to deliver the clinical promises of hESCs. Here, we describe the basic principles of growing hESCs in a chemically defined medium (CDM) devoid of serum and feeders.
