A Review of the Material Characteristics, Antifreeze Mechanisms, and Applications of Cryoprotectants (CPAs)

Abstract

Cryopreservation has been a key technology in medical science, food preservation, and many other fields. In a freezing process, the formation of ice crystals may cause significant damage to the frozen samples. In order to reduce the damage, many cryoprotectants (CPAs) have been developed and added in cryopreservation processes for reduced ice volume, decreased ice size, proper ice shaping, and cell protection. According to the material characteristics, the CPAs are either impermeable (i.e., antifreeze protein, polyampholytes, and polyvinyl alcohol) or permeable (i.e., dimethyl sulfoxide, proline, and glycerol) to cell membranes. The typical CPAs are introduced in this work with their material characteristics, antifreeze mechanisms, and applications. Antifreeze mechanisms for different CPAs involve molecular adsorption on the ice surface, hydrogen bonding to ice, bending the ice surface, lowering the freezing point, inhibiting ice recrystallization, protecting cell membranes, reducing dehydration of cells, and breaking hydrogen bonds among ice crystals to reduce the size of ice crystals. In practice, different CPAs can be used together with their cryopreservation properties functioning synergetically. This study reviews the recent applications of CPAs in food, biology and medicine, and agriculture. Future works for CPAs are suggested in improving efficiency, revealing mechanisms, broadening application, and finding new CPAs.

Exploring the application and mechanism of sodium hyaluronate in cryopreservation of red blood cells

“…During the thawing process, small ice crystals will disappear and large ice crystals will grow up. It is known as ice recrystallization and is in line with the Ostwald ripening [ 37 ]. The large ice crystals formed by recrystallization are fatal to cells.…”

Antifreeze Proteins: Novel Applications and Navigation towards Their Clinical Application in Cryobanking

“…The extensive clinical application of AFPs has also been hindered by toxicity and immunogenic responses [ 7 ] as seen in the diminished survival of human embryonic liver and kidney cells after AFP treatment [ 162 , 163 ]. Another problem is the formation of sharp bipyramidal extracellular ice when a high AFP concentration is applied [ 115 ], which would be detrimental during cryopreservation via vitrification.…”

“…or impermeable (polyvinyl alcohol (PVA), polyampholytes, trehalose, sucrose, graphene oxide, etc.) based on whether they can cross cell membranes [ 7 ]. There is a limit to which CPAs can be used owing majorly to toxicity and adverse reactions [ 8 ].…”

Novel synergistic freezing methods and technologies for enhanced food product quality: A critical review

“…A. Raymond et al., 2007; Xiao et al., 2010), plants (Baskaran et al., 2021), arthropods (Kristiansen et al., 2011), and fish (Devries & Wohlschlag, 1969). These proteins restricted the enlargement of ice to a specific size for a long time by keeping the melting point and freezing point (Baskaran et al., 2021; Davies, 2014; Liou et al., 2000; X. Liu et al., 2021). Under this mechanism, a row of impurity molecules completely blocked a step, thus, forcing the crystal to grow in a two‐dimensional nucleation mode, which is a very slow process (Chen et al., 2020; Devries & Wohlschlag, 1969; Graether et al., 2000).…”