What is Stability and Durability in Vitrification?
Vitrification is a method used for cryopreservation of eggs and embryos. It involves an ultra-rapid cooling process that leads to a glass-like solidification without crystallization. To avoid intracellular crystals, before freezing, the embryos/eggs are exposed to cryoprotectant that draws out water out of their cells.
The three factors that affect the stability and durability in vitrification process are:
- Cooling and warming rates
- The composition of cryoprotectant solution
- The volume of cryoprotectant solution
Cell toxicity and osmotic pressure created by the high concentration of cryoprotectant solution is one of the main risks associated with the vitrification process. In order to limit this, the exposure time of the eggs/embryos in the cryoprotectant solution must be reduced or the cooling rate must be increased by decreasing the sample volume.
This can be achieved by specially designed storage devices that would allow rapid cooling and also reduce the amount of solution surrounding the embryos or the eggs. Thus the durability and stability in vitrification of embryos and gametes can be maintained.
An innovative method of vitrification implemented these days is by using sealed pulled straws that reduces the risk of any contamination during the vitrification process and also maintain a high cooling rate in liquid nitrogen slush.