This is a process that is used to preserve stem cell by cooling them at sub-zero
temperatures for future use. This process is also used in infertility treatments
to freeze sperms, embryos, and ova. The technique is still new and is yet to achieve
perfection, though is highly popular among scientists to preserve samples of their
research. It is used by hospitals and research institutes.
- Cryoprotectants- help in rapid freezing of the substance, turning
it into a glass like state that does not have any crystal like formation. They protect
the cells from getting killed and lower the freezing point. They also ensure that
there is no intra cellular or extra cellular ice formation. The concentration of
cryoprotectants is maintained based on the cells that have to be preserved. High
concentration may result in harmful chemical reactions.
- Liquid nitrogen- This is the main agent in which the samples
are stored. Since the boiling temperature of liquid nitrogen is extremely low (-195.8
º C), it is the perfect medium to carry out cryopreservation. Usually, the substances
are stored at 77 K or -196˚C. The rate at which cooling tales place has to be maintained
as improper cooling techniques can destroy the cells.
De-freezing or thawing is done rapidly using special techniques, so that the cells
do not get damaged. Post this, the cells get coaxed into differentiating into a
particular cell type and introduced into the patients body.