Theoretical Estimation of the Optimum Cooling Rate of a Cell Suspension at Linear Freezing Modes Based on a Two Factor Theory of Cryodamage.

BACKGROUND: According to the two-factor theory cryodamage arises from intracellular crystallization and solution effects due to freeze concentration. OBJECTIVE: The study aims to evaluate the contribution of two types of cryodamages that are related to extra- and intracellular crystallization. METHODS: The probability of intracellular crystal formation during cooling of cell suspension in cryoprotective solution has been determined based on general thermodynamics theory. RESULTS: According to the obtained correlations and taking into account of the individual characteristics of yeast cells and murine enterocytes, the optimal cooling rates during freezing of these cells in cryoprotectant solutions were determined. CONCLUSION: The proposed algorithm for the estimation of the optimal cooling rates at linear freezing mode of a particular cellular suspension can be utilized to develope methods for cryopreservation of different cell suspensions.

DEVELOPMENT OF A MODEL TO INVESTIGATE RED BLOOD CELL SURFACE CHARACTERISTICS AFTER CRYOPRESERVATION.

BACKGROUND: Maintaining cell surface properties after freezing and thawing, characterized in particular by the surface potential and associated with it cell ability to intercellular adhesion, could be used as a characteristic of successful cryopreservation. OBJECTIVE: This study was conducted to research applying different erythrocytes freezing modes and analyses the regimes cryopreservation effect on the cell surface charge and adhesion to microorganisms. MATERIALS AND METHODS: Human erythrocytes frozen by three modes. In order to determine adhesion index was used dried bacterial cells of S. thermophilus. The surface charge of erythrocytes was evaluated using Alcian blue cationic dye. RESULTS: The results showed the significant decrease in the lactobacillus adhesion to erythrocytes frozen glycerol and 1,2-propanediol. After erythrocytes were freezen with glycerol and 1,2-propanediol, the cationic dye binding to erythrocytes significantly reduced. AB binding to erythrocytes frozen with PEG-1500 does not differ from control data. CONCLUSION: Erythrocytes frozen with PEG-1500 mantained surface properties after thawing better, compared to erythrocytes cryopreserved by other methods.