抄録
To examine the cryoprotective role of glycerol in preserving frozen red blood cells, we used a differential scanning calorimeter (DSC) to study the thermal behavior of the clinically used glycerol-based cryoprotective solutions (complex system) as well as the glycerol-water (binary) system. We found two peculiar zones in which freezing occurs without the formation of ice crystals: an amorphous state (glycerol concentrations between 45% and 60% for the complex system and between 40% and 55% for the binary system) and a gelation state (for glycerol concentration greater than 60% for the complex system and 55% for the binary system). However, clinically used cryoprotectants are not used in either of these states, but are used in the zone with cryoprotectant concentration lower than that for which the amorphous state occurs. This attributes to an increase in the effective glycerol concentration inside and outside the cells because ice forms during freezing.
