Devitrification Thresholds and Warming Rates of Reproductive Cells

Special attention during the manipulation, storage, and transport of vitrified samples is of paramount importance since warming increases the risk of devitrification or recrystallization, which causes cell death. Devitrification is the phenomenon where ice is formed during warming; the glass transition temperature (Tg) of the medium is essential for the knowledge of thermal transitions during clinical activities. Mathematical modeling can be used to analyze complex thermal phenomena; it can be applied to evaluate critical cooling and warming times, new storage designs, and inventory procedures prior to exposing real-life samples. A multidisciplinary approach to determine time-temperature histories of vitrification devices allowed the prediction of devitrification thresholds and how these may affect storage and handling conditions of the samples. The complex equations that govern the energy transfer of samples in a Dewar tank and the temperature profile inside the tank under different conditions showed that devitrification can be achieved causing a harmful situation. These results were validated with in vitro embryo development using a bovine model; therefore, they reinforce the importance of exercising extreme cautions while handling vitrified material during routine laboratory procedures such as identification, confirmation, and inventory keeping.