A controlled rate freezer is a programmable cryopreservation device that lowers the temperature of biological samples at a precisely defined and reproducible rate — typically between -1°C and -3°C per minute for the slow-cooling protocols most commonly used in IVF and andrology. The device allows the operator to programme a specific cooling curve that matches the protocol requirements for the sample type being cryopreserved.
The controlled cooling rate is designed to allow water to exit the cell osmotically during the slow temperature drop, reducing the formation of intracellular ice that causes mechanical cell damage. At the rates used in slow-cooling protocols, the cell has time to equilibrate with the external cryoprotectant solution as the temperature drops, minimising osmotic stress alongside ice formation risk.
Controlled rate freezers are most commonly used in IVF laboratories for sperm banking, where slow-cooling remains the standard cryopreservation approach for most andrology units. They are also used for red blood cell cryopreservation and for certain cell lines in research settings where vitrification is not the appropriate method. Cryolab supplies the CBS DigitCool range of controlled rate freezers. Contact Cryolab to discuss the right model for your programme’s cooling protocol requirements.
