Fig. (9) Cell survival as a function of cooling rate due to intracellular ice formation (IIF) only (➀), freeze concentration induced cell dehydration (solute effect) only (➁), and the combination of the two factors (➂ and ➃): During slow-freezing, the solute effect and IIF determines cell survival at low and high cooling rates, respectively; the combined effect of IIF and freeze concentration (i.e., solute effect) results in the classical inverted U curve of cell survival vs. cooling rate and an optimal cooling rate (CRSF) is observable for slow-freezing; the optimal cooling rate is cell type and also cryoprotectant concentration dependent; and when the cooling rate is higher than a critical cooling rate (CRV), cells are vitrified without freezing (or ice formation) and high cell survival ensues. Figure reprinted from reference [53] with permission from Xiaoming He (the author).