Cryopreservation is a process where cells or whole tissues are preserved by cooling to sub-zero temperatures.
At Coriell, cell lines are stored in sealed Pyrex vials at -316 degrees Fahrenheit liquid nitrogen. At this low temperature, any biological activity – including biochemical reactions that would lead to cell death – is effectively stopped, providing an indefinite longevity to cells. For establishing and biobanking a cell line, the following steps are critical:
- The process begins when a blood sample from a subject with a genetic disease arrives at Coriell.
- The specimen is labeled with a barcode tracking number and information about the specimen is recorded in Coriell’s database. At least two technicians check each step for accuracy. A sample of the specimen is removed and its DNA tested for later reference.
- The blood sample is spun through a centrifuge to separate it into its different parts. White blood cells are removed with a pipette and placed in a flask along with a growth-enhancing solution. The flask is then incubated at body temperature and the cells are allowed to grow from three weeks to three months.
- The cells are checked throughout the culturing process to ensure they are growing properly.
- The cells are then transferred into three or four larger flasks and allowed to continue growing.
- After a week, they are placed in a large vessel and allowed to grow for another three to four days. The vessels are kept in racks that turn slowly to facilitate cell growth.
- The cells are placed in glass ampules along with cryo-preservative. Each ampule holds about 1 million cells. For quality control purposes, DNA from the cells is verified against the sample taken when the blood first arrived.
- The tops of the ampules are then sealed with a flame, so that the cells can be submerged in liquid nitrogen.
- Six ampules are snapped into a thin metal frame called a “cane.” Each cane holds cells taken from the same individual.
- Before being immersed in a cryogenic storage tank filled with liquid nitrogen, the cells are cooled down in one of three controlled-rate freezers. The samples are cooled down this way to prevent them from being damaged.
- Canes are put into numbered canisters in a tank filled with liquid nitrogen. Each canister can house 20 canes; each tank can hold up to 306 canisters. When filled to capacity, each Coriell tank holds 6,120 canes, up to 36,720 ampules. Each of Coriell’s 100 tanks is preserving millions of cells indefinitely.
- Researchers around the world search Coriell’s online database, which contains more than 800 genetic diseases. When a sample is requested, it is retrieved, thawed, quality checked, and shipped within days. Coriell ships approximately 8,000 cell cultures and 100,000 DNA specimens each year.