Synth-a-Freeze® is a defined, liquid cryopreservation medium containing 10% dimethylsulfoxide (DMSO) without antibiotics, antimycotics, hormones, growthfactors, serum or protein and buffered with HEPES and sodium bicarbonate. Synth-a-Freeze is intended for freezing and storing a variety of mammalian cell types including human keratinocytes, embryonic stem cells, neural stem cells and mesenchymal stem cells. It should not be used for melanocytes.