Development and Application of Cryoprotectants

Cryopreservation involves the preservation of biological materials, including cells, embryos, tissues, and organs, at ultra-low temperatures (in a state of suspended animation), for a long period of time, and in a way that allows them to be restored whenever required. Freezing of biological samples is generally accompanied by numerous undesirable outcomes such as intra- and extracellular freezing damage and osmotic stress. To prevent these adverse effects, cryoprotective agents (CPAs) are added to biological materials before freezing. Over the years, a number of CPAs have been identified and developed and have been employed successfully for numerous applications. Here, we review the history and development of cryoprotectants and the current understanding of the cryopreservation process. We conclude with a discussion about the application of cryopreservation for various clinical and academic studies.