This study investigates the freezing behavior of rat hepatocytes under different physical and chemical conditions using thermodynamic models and cryomicroscopic observations. Comparisions were made between freshly isolated cells and cells cultured between two layers of collagen gel. Parameters which describe the freezing behavior of hepatocytes under various conditions (i.e. water permeability coefficients and ice-nucleation parameters) were obtained. The water permeability was determined to be 9.3 and 1.27 μm/min-atm at 0°C for isolated and cultured hepatocytes, respectively. The temperature dependence of the water permeability in the range of 0° to -10°C was given by an Arrhenius relationship with an activation energy of 81 and 18 kcal/mole for isolated and cultured hepatocytes, respectively. With respect to intracellular ice formation, the kinetic parameters describing the addition of water molecules to the ice-nucleation site were 110 × 108 1/m2s for isolated hepatocytes and 54 × 108 1/m2s for cultured hepatocytes; the thermodynamic value for the energy barrier to ice-nucleation was 1.4 × 109 K5 for isolated cells and 0.3 × 109 K5 for cultured cells. The values of the nucleation parameters suggest that the ice-nucleation is catalyzed heterogeneously for both isolated and cultured hepatocytes. These model parameters were used in the theoretical model to predict the freezing behavior and the predictions were compared to experimental observations. The results from this study suggest that an intact extracellular matrix has a significant effect on the freezing behavior of hepatocytes.
|Original language||English (US)|
|Number of pages||2|
|Journal||Annals of Biomedical Engineering|
|State||Published - Dec 1 1991|
|Event||1991 Annual Fall Meeting of the Biomedical Engineering Society - Charlottesville, VA, USA|
Duration: Oct 12 1991 → Oct 14 1991