An Adiabatic Calorimetry Method to Determine the Thermodynamic Characteristics of Cryoprotectants

Аннотация

Abstract—The efficiency of cryoprotectants used to protect cells from damage is usually evaluated by the changes in vital cell parameters after a freezing–thawing cycle. Certain physical parameters, such as the glass transition temperature, viscosity, toxicity, and the minimum concentration necessary for vitrification, are known for several components of cryoprotectants. However, it is impossible to provide physicochemical characteristics for a medium that contains both penetrating and nonpenetrating cryoprotective agents. An adiabatic calorimetry method adapted to studying liquid media was used to describe the temperature dependence of the heat capacity and to find the temperatures of the phase transition and changes in the state of aggregation for a glycerol-containing solution, which is commonly used as a basic component of cryoprotectants, and for a commercial cryoprotectant. Changes in entropy and enthalpy in the commercial cryoprotectant were 1.5 times higher than in aqueous solutions of glycerol.