Xeno-free culture medium does not contain fetal bovine serum but uses human blood serum or platelet lysates instead.
One hurdle to clinical applications of human embryonic stem cells and human iPS cells is the elimination of possible contamination with animal components which may introduce pathogens and cause immune rejection after transplantation. Mouse embryonic fibroblasts (MEFs) are commonly used as a feeder layer of growth-arrested cells which secrete factors that maintain the overlying stem cells in an undifferentiated state. Feeder layers of human origin include human foreskin fibroblasts, human dermal fibroblasts and amniotic mesenchymal. Other cell culture components allow the culturing of human stem cells without feeder cells, such as Matrigel and Geltrex but these products are not xeno-free because they contain extracts from mice.
Cell biomaterials have been developed for feeder-free and xeno-free conditions such as dishes coated with recombinant extracellular matrices (ECM) proteins. Completely synthetic dishes have also been developed for human pluripotent stem cells. The elasticity of cell culture matrices is important for maintaining pluripotency.
CELLstart is a xeno-free substrate for attachment and expansion of human embryonic, mesenchymal, and neural stem cells offered by ThermoFischer Scientific.
