[Cryobiology-- freeze preservation and storage of living cells and tissues].

BACKGROUND: Freeze preservation and prolonged storage of living cells and tissue fragments have been met with increasing interest in medicine during the recent years, for diagnostic, therapeutic as well as research purposes. METHODS: The main methods: Programmed freezing, where a gradual decrease of temperature, usually 1 degrees C per minute is used, and vitrification: rapid freezing transforms cells and liquids to a solid state. In both cases chemical substances and macromolecules are added to reduce the risk of deleterious crystal formation in water. Such frozen cells can be stored for more than 10 to 15 years and retrieved in a viable condition. RESULTS AND INTERPRETATION: At present such techniques are used in reproductive medicine, with storage of human embryos after in vitro fertilization. In addition, there cells are increasing used for other therapeutic purposes, from haemopoietic stem cells to tissue fragments from skin and joint cartilage. Large biobanks of living, frozen cells are now being established in several countries.