Cord Blood Preservation
The Freezing Process
After the stem cells have been processed, the production of cord blood preservation begins. However, this must be done slowly and carefully in order not to damage the stem cells.
How it Happens
Before the umbilical blood is frozen, it will first be introduced to a solution to help prevent it from being damaged while frozen. This solution is referred to as the cryopreservation solvent or cryoprotectant.
Once the blood has received this, it will begin to slowly be frozen. Freezing it gradually is used as another preventative measure in guarding the cells against damage.
Once the blood is frozen to a temperature of -196 degrees Celsius, it is transferred to a permanent storage freezer. While in this freezer, it will remain frozen through the use of either liquid or vapor nitrogen.
There are two different types of freezers commonly used in the preservation of cord blood stem cells.
The first is the "BioArchive" freezer. This machine not only freezes the blood, but also inventories it and manages up to 3,626 blood bags. It has a robotic arm that will retrieve the specified blood sample when required. This ensures that no other samples are disturbed or exposed to warmer temperatures.
The second freezer system is the ï¿½dewarsï¿½ which is the most commonly used freezing system in the USA. This unit is basically a well-insulated container with a lid. Because the lid needs to be opened every time a sample goes in or out of the freezer, there is a risk of the other samples being compromised. However, to help guard against this, temperatures on these freezer units are vigorously maintained and monitored.
Inside the Freezer
Cord blood cell samples are either stored in bags or vials inside the freezers. Most cord blood banks will use only one type of storage since the bags or vials need to be evenly spaced on the racks inside the freezer. Therefore, the racks tend to be equipped to accommodate only one type of storage container. However, a few banks do use both bags and vials to store the cord blood. They have separate freezer units for each type of storage.
A stem cellsï¿½ viability in the freezer has yet to be definitely determined. Some scientists are conservative and put its freezer life at 10 years while most others say 15 years. Many are hoping and expecting the stem cells will be viable for up to 20 years, but studies have yet to conclusively determine this.