Cryoprotectants, also known as cryoprotective agents (CPAs), are chemical compounds added to biological samples prior to freezing to protect cells, tissues, and organs from the damaging effects of cryogenic temperatures. Since the landmark discovery by Polge and colleagues in 1949 that glycerol dramatically increased the recovery of viable spermatozoa after freezing, numerous chemicals with cryoprotective properties have been identified. Cryoprotectants function by reducing ice crystal formation, moderating osmotic stress, and stabilizing cellular structures during the freeze–thaw cycle, making them indispensable across biobanking, cell therapy manufacturing, and reproductive medicine.
Applications
Cryoprotectants are employed across a broad spectrum of biomedical applications. In reproductive medicine, glycerol and DMSO are used for sperm cryopreservation, while sucrose and trehalose are widely employed in oocyte and embryo vitrification protocols. In cell therapy manufacturing, cryoprotectants enable the preservation of CAR-T cells, mesenchymal stem cells, and pluripotent stem cells. In biobanking, cryoprotectants facilitate the long-term storage of cells and tissues at liquid nitrogen temperatures. In tissue engineering, cryoprotectants are used to preserve engineered tissues and organ constructs.
