. A quicker phase change is known to diminish
ice crystal size, causing the formation of intracellular crystals which does
not favor the viability of frozen suspended cells. Ultrasound-assisted irradiation
at higher temperatures (−2 and −4 °C), on the other hand, increased
the viability of the cells significantly. Ultrasound irradiation (for
4 min from −2 °C for MRS or −4 °C for MRS with 5% DMSO) during
the phase change stage of the freezing process further increased the viability
of the cells while reducing the freezing time