Definition - What does Cryoprotectant mean?
A cryoprotectant is a chemical compound that prevents damage to cells during freezing, thereby maintaining its viability. Cryoprotectants are used during cryopreservation techniques, a method of cooling and storing eggs, embryos, and sperm.
The use of cryoprotectants ensures that the eggs, embryos, or sperm are not damaged during the freezing process and are preserved for future pregnancy attempts.chr
FertilitySmarts explains Cryoprotectant
After the retrieval of the eggs/sperm or embryos, they are rinsed, incubated, and prepped for freezing. During the freezing process, the temperature drops from 37 degrees Celsius where most cells are biologically active to -196 degrees Celsius or -321 degrees Fahrenheit in liquid nitrogen. At this low temperature, biological activity stops— including the processes that lead to the degradation of DNA and cell death.
Some of the problems that occur with freezing biological tissue are the formation of ice crystals, membrane damage, and osmotic shock which will lead to the death of the cell. Cryoprotectants help the cells to survive both the cooling and the thawing process.
There are two types: permeating cryoprotectants spread throughout the membrane of the cell forming bonds with water molecules to prevent ice crystals from forming and non-permeating cryoprotectants that remain outside of the cell and work by drawing free water from inside the cell, out thereby dehydrating it.
Once the gametes or embryos have been frozen, they can be stored for an extended period of time.