Fig. 1.

Temperature profile of controlled-rate freezer (CRF) and isopropyl alcohol (IPA) containing cryopreservation containers. The CRF cryopreservation procedure for 2 × 10⁸ PBMC/ml was configured by the following program parameters: −10 °C/min to 0 °C, −1 °C/min to −12 °C, −4 °C/min to −20 °C, hold for 5 min at −20 °C (preventing the crystallization heat that may result in a slight temperature increase at this stage), −1 °C/min to −40 °C, −3 °C/min to −80 °C, hold for 6 min at −80 °C. IPA freezing reached a temperature of −42 °C after 60 min. The rate of temperature decline in the IPA containers constantly decreased, reaching −80 °C finally after 300 min