Effect of common cryoprotectants on critical warming rates and ice formation in aqueous solutions

Abstract

Ice formation on warming is of comparable or greater importance to ice formation on cooling in determining survival of cryopreserved samples. Critical warming rates required for ice-free warming of vitrified aqueous solutions of glycerol, dimethyl sulfoxide, ethylene glycol, polyethylene glycol 200 and sucrose have been measured for warming rates of order 10 to 104 K/s. Critical warming rates are typically one to three orders of magnitude larger than critical cooling rates. Warming rates vary strongly with cooling rates, perhaps due to the presence of small ice fractions in nominally vitrified samples. Critical warming and cooling rate data spanning orders of magnitude in rates provide rigorous tests of ice nucleation and growth models and their assumed input parameters. Current models with current best estimates for input parameters provide a reasonable account of critical warming rates for glycerol solutions at high concentrations/low rates, but overestimate both critical warming and cooling rates by orders of magnitude at lower concentrations and larger rates. In vitrification protocols, minimizing concentrations of potentially damaging cryoprotectants while minimizing ice formation will require ultrafast warming rates, as well as fast cooling rates to minimize the required warming rates.

Preparation of Scalable Silica‐Coated Iron Oxide Nanoparticles for Nanowarming

“…[7,8] However, even if this is achieved, rewarming requires a much faster critical warming rate (CWR), such as 50 °C min −1 for VS55 [8c] to avoid devitrification (i.e., ice formation during the rewarming). [9] Convective heating by immersion in a warm water bath is adequate for samples with volumes below 3 mL and cells in suspension or small tissues in a cryovial or cryobag. However, convective warming is often too slow to achieve needed CWR in larger samples (>3 mL) due to the inability to quickly warm the center of the sample, thereby leading to devitrification.…”

Cryoprotectant-free cryopreservation of mammalian cells by superflash freezing

“…5 and Movie S4 and summarized together with the cooling and survival rates in Table 1. The estimated warming rates were approximately three to four times higher than the corresponding cooling rates, whereas the critical warming rates of several solutions were reported to be one to three orders of magnitude higher than the CCR (32). The critical warming rate for cells (CWR cell ) was estimated to be 10 5°C /s, which is one order of magnitude higher than CCR cell .…”

Benefits and Constraints of Vitrification Technologies for Cryopreservation of Bovine in vitro Fertilized Embryos

“…Recent studies have considered the role of warming rates in determining the fate of vitrified cells [18,22]. According to Hopkins et al [23] differences in warming rates are correlated directly with prior cooling rate because of the accumulation of tiny ice fragments in vitrified cells. A faster cooling rate is required for a corresponding warming rate to block recrystallization [22].…”