Visualization Study on Ice Formation in Water and Dimethyl Sulfoxide Solution

Abstract

Ice formation during freezing and rewarming processes is a key factor that affects the success rate of cell cryopreservation. The discovery of the formation and inhibition mechanism of ice crystals in various scenarios is highly significant for clinical applications, such as fertility treatments and assisted reproduction. A new cryomicroscopy system based on the instant contact method was developed, which achieved a cooling rate of up to 1600 K/min. The system was used to study the freezing process of pure water and dimethyl sulfoxide solution on a plate and in a circular channel under different supercooling conditions. The crystallization behavior of rat seminiferous tubules in pure water and 10% dimethyl sulfoxide solution was compared. Compared with pure water, the ice formation process of the dimethyl sulfoxide solution occurred more randomly at different positions on the plate with a slower growth rate. In the circular channel, the ice formed by pure water was mainly in the shape of a sharp needle, whose growth rate increased with the increase in the degree of supercooling. The ice formation outside the seminiferous tubules of rats was weakened by the addition of dimethyl sulfoxide; hence, the seminiferous tubules retained their physiological morphology.

Keywords

• cell cryopreservation
• ice formation
• cryoprotectant
• cryomicroscopy