What is cryopreservation?
Cryopreservation is the use of antifreeze (cryoprotectant) solutions and of cooling to very low temperature on humans, animals, organs or tissues for long-term storage − typically liquid nitrogen temperature (-196°C). If freezing can be avoided − as with vitrification − cryopreservation is not freezing.
Cryopreservation means preserving in a frozen condition. The best known cryopreservation is of semen. This is mostly done in case of cancer of the testicles before treatment of the cancer. Furthermore cryopreserved semen is used in donor insemination. It is also possible to freeze fertilised eggs after IVF or ICSI. If more embryo’s are left after an IVF or ICSI procedure they can be frozen and transferred another time. In this way there is more chance on a pregnancy while only one IVF or ICSI cycle is performed. For human oocytes cryopreservation is much more difficult. Only in very few experiments this is done successfully. The attention of researchers now is on developing a way to freeze ovarian tissue and after thawing, to obtain the oocytes in it. This procedure is not yet fully refined but when it is it can offer great opportunities in the future.
