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Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. [1] At low temperatures (typically −80 °C (−112 °F) or −196 °C (−321 °F) using liquid nitrogen ) any cell metabolism which might cause damage to the biological ...
At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of microorganisms, plants (cold hardiness), and animals, both invertebrates and vertebrates (including hibernation), 2) cryopreservation of cells, tissues, gametes, and embryos of animal and human origin for (medical) purposes of long-term storage by cooling to temperatures below the freezing point of water.
There are two common techniques of cryopreservation: slow freezing and vitrification. Slow freezing helps eliminate the risk of intracellular ice crystals. [16] If ice crystals form in the cells, there can be damage or destruction of genetic material. Vitrification is the process of freezing without the formation of ice crystals. [17]
Cryofixation is a technique for fixation or stabilisation of biological materials as the first step in specimen preparation for the electron microscopy and cryo-electron microscopy. [1]
Cryopreservation itself has always played a central role in assisted reproductive technology. With the first cryopreservation of sperm in 1953 and of embryos twenty five years later, these techniques have become routine. Dr. Christopher Chen of Singapore reported the world's first pregnancy in 1986 using previously frozen oocytes. [2]
A cryoprotectant is a substance used to protect biological tissue from freezing damage (i.e. that due to ice formation). Arctic and Antarctic insects, fish and amphibians create cryoprotectants (antifreeze compounds and antifreeze proteins) in their bodies to minimize freezing damage during cold winter periods.
The use of cryopreservation agents is also key to the freezing process. A common cryoprotection agent used is 10% solution of DMSO, which acts to protect the cells from the rupturing caused by ice crystals during freezing and during thawing. DMSO has been observed to be toxic to cells, and requires dilution after the cells are thawed. [8]
There are two general approaches for RBC cryopreservation, referred to as the high- and the low-glycerol method. Glycerol serves as cryoprotectant in both. The high-glycerol method uses 40% weight/volume glycerol, a slow freezing rate (1–3 °C per minute) and allows storage of the frozen red blood cells in common mechanical −60–80 °C ...