Franks F, Mathias S F, Galfre P, Webster S D, Brown D
Cryobiology. 1983 Jun;20(3):298-309. doi: 10.1016/0011-2240(83)90018-4.
DSC has been employed to study the effect of cooling on a range of cells under exclusion of extracellular ice and in the absence of chemical cryoprotectants. In contrast to earlier reports, all the cells studied were found to freeze at temperatures above that indicated for homogeneous nucleation of ice in undercooled liquid water. In the case of human erythrocytes this temperature difference was only 0.5 degrees, but for yeast cells and cells of plant origin the difference amounted to congruent to 9 degrees. Nucleation of ice within the cell (or at the cell wall/membrane) must therefore be initiated by a heterogeneous mechanism. A kinetic analysis of the temperature dependence of nucleation shows the rates to be consistent with the dimensions of the plant cells (or organelles), if these were to be the active nucleators. However, the nucleation kinetics of human erythrocytes are extremely temperature sensitive, and the kinetic parameters only differ by small, though significant, extents from those of the suspension medium. Possible nucleation mechanisms are discussed in terms of the experimental data and the cell dimensions. Finally, one of the underlying assumptions of the kinetic analysis, i.e., that ice growth must be rapid compared to nucleation, has been tested and validated by freeze-fracture electron microscopy.
差示扫描量热法已被用于研究在排除细胞外冰且不存在化学冷冻保护剂的情况下，冷却对一系列细胞的影响。与早期报告不同的是，研究发现所有细胞均在高于过冷液态水中冰的均匀成核温度下冻结。就人类红细胞而言，该温度差仅为0.5摄氏度，但对于酵母细胞和植物来源的细胞，该差值达9摄氏度左右。因此，细胞内（或细胞壁/细胞膜处）的冰成核必定是由非均匀机制引发的。对成核温度依赖性的动力学分析表明，如果植物细胞（或细胞器）是活性成核剂，那么成核速率与植物细胞（或细胞器）的尺寸相符。然而，人类红细胞的成核动力学对温度极为敏感，其动力学参数与悬浮介质的动力学参数相比，虽差异不大，但仍具有显著性。根据实验数据和细胞尺寸对可能的成核机制进行了讨论。最后，通过冷冻断裂电子显微镜对动力学分析的一个基本假设，即冰生长速率必须比成核速率快，进行了检验和验证。
