MU INACTVTD EMBRYONIC FEEDERS 1 ML，A24903，Invitrogen

Mouse embryonic fibroblasts (MEFs) are used as a feeder layer when culturing mouse and human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). They are isolated from mouse (strain ICR) embryos. The cells are expanded and inactivated by γ irradiation and cryopreserved. Prior to cryopreservation, the cells are tested for viability (>80% post-thaw viability), verified for growth arrest by plating inactivated cells at low density and monitoring for foci of cell growth after 14 days in culture, and also tested for their ability to support growth of mouse embryonic stem cells (mESCs), human embryonic stem cells (hESCs), and marker expression (Oct 4).