Why do bags crack and break after being frozen and thawed?
The Failure of Cryopreservation Bags To Breakage- The reason for freezing bag failure has not been widely recognized. Bags fail because of carbon dioxide. The products frozen are living cells that have been maintained in nutrient rich tissue culture media prior to freezing. The cells metabolize sugars and produce carbon dioxide, which is initially carbonic acid or completely dissolved carbon dioxide. As the culture of cells awaits freezing it is usually taken from an incubator or room temperature and cooled in a refrigerator or on ice in preparation for the addition of DMSO or other cryoprotectant. During this ‘cold incubation’ production of carbon dioxide continues, and at lower temperatures the media has greater solubility for carbon dioxide so the solution accumulates large amounts of dissolved carbon dioxide. Then the cryoprotectant is added to the cold solution. The reason for doing this cold is that the DMSO dilution has a very large exotherm and the osmolality goes above 2000 mi
