Observation of thawing process for cryopreservation in milliscale cell

The purpose of this study is to investigate a method of thawing a milliscale biological cell used for cryopreservation. The rewarming system was equipped with a heater and copper block immersed in liquid nitrogen (-196°C), and regulated the warming rate of the test section from 0.1 to 100°C/min over the temperature range -196 to 0°C. A killifish embryo was placed at the tip of the test section (a truncated cone) with a drop of 15% dimethylsulfoxide-water and cooled to -196°C. To avoid recrystallization, it was rewarmed at a rate of 100°C/min to -7°C and at various rates from -7 to 6°C. After thawing, the morphology of the embryo was observed. As a result, a warming rate of 0.3°C/min was found to be optimum for morphological preservation. The warming rate should be rapid up to the extracellular melting point and slow during thawing.