Cryogenic freezing involves rapidly cooling biological material to very low temperatures, typically between -196°C and -140°C. At Acorn we achieve this by using specialized procedures and materials to protect the cells and use liquid nitrogen as a way to safely store the samples at these temperatures. 

To freeze the hair follicles, they are first immersed in a cryoprotective solution, which helps to prevent ice crystals from forming and damaging cells during the freezing process. The material is then cooled at a controlled rate using a highly specialized programmable freezing device. Once frozen, the cells only require liquid nitrogen to remain frozen. 

When it is time to thaw the biological material, it is carefully removed from storage and slowly warmed to room temperature. This process also is done with controlled rate to avoid any thermal shock.