Cryopreservation

Cell lines are stored by cryopreservation. A cryoprotective agent (dimethyl sulfoxide, DMSO) is added to the culture . The freezing medium in which the cells are also stored is indicated for each individual cell line. In general, we use 7 volumes medium, 2 volumes fetal bovine serum, and 1 volume DMSO.
Frozen ampoules are stored in liquid nitrogen (LN2) at -196 ̊C. Cell viability in LN2 is maintained over a very long time (>10 years or more), provided, of course, that ampoules are continuously exposed to the gas or liquid phases.