**Table 4.**

*Cooling and warming rates of different vitrification methods.* 

(1) viscosity of the CPA solution; (2) cooling rate; and (3) sample volume. Thus, a delicate balance must be maintained among these factors to achieve successful vitrification [1]. Vitrification can be achieved with a CPA concentration of 5–7 M and a cooling rate of approximately 2500°C/min [28]. A major advantage of vitrification is the low risk of freezing injury, thereby ensuring a sufficiently high cell survival rate.
