Measurement of critical osmotic pressure of biological cells (Minimum cell-to-volume ratio as an estimation of viability)

The critical osmotic pressure that can be endured by biological cells is me asured. Optimal parameters of the freezing process as well as the prefreezi ng process are restricted by the critical osmotic pressure, which can be tr anslated. into the critical normalized volume of the cell. Viability of the cells is measured after the cells are exposed to a certain osmotic pressur e, and the viability can he estimated from the viewpoint of biophysical fun ctions. In this study, endothelial cells and smooth muscle cells comprising porcine arteries are selected as samples. The viability of endothelial cel ls is estimated by a dye-exclusion test, and that of smooth muscle cells is estimated by measuring the contraction-relaxation rate. Optimal parameters of the freezing process as well as the prefreezing process can be obtained by estimating the normalized volume of the cell. The critical normalized v olume of cells can be estimated from the measured critical osmotic pressure .