Many cells can be preserved and remain viable by freezing. However, the conditions during freezing must be carefully controlled and monitored.
Electrolyte solutions, such as sodium chloride, are not good media in which to freeze cells because during freezing the
concentration will increase around the cells causing osmotic stress.
solution, such as a sugar solution, is better than an electrolyte solution, but sugars will only affect the extracellular electrolyte concentration and will not enter the cells.
An optimal type of freezing medium is one that is permeable to cells.
is one compound that is ideal for freezing cells. While the solution is hypertonic to cells and water leaves the cells, this solution will also enter cells at the same time to stabilize the internal and external cellular environment.