Frostbite happens when your body is exposed to such cold temperatures that blood cannot make it to the extremities. This results in ice crystallization, irreparably shredding cells and destroying tissue. While scientists need to use cold temperatures to preserve biological tissues, they must be careful to avoid the formation of these damaging ice crystals. Boris Rubinsky’s laboratory in the mechanical and bioengineering departments has developed an approach called isochoric vitrification which allows for sample preservation without ice crystallization.

Ice takes up more volume than liquid water—think of how a frozen bottle of water bulges in the freezer. Isochoric vitrification leverages this thermodynamic relationship by keeping the sample volume constant using a rigid aluminum chamber. The chamber is plunged into a liquid nitrogen bath and the temperature drops. The volume of the sample cannot increase, thus preventing ice crystal formation and preserving the sample in a glasslike state.

The team partnered with the Smithsonian’s National Zoo and Conservation Biology Institute and the Hawaii Institute of Marine Biology to apply this technique to coral sample preservation. Coral bleaching, caused by rising water temperatures linked to climate change, is wiping out coral reefs. To prevent the loss of coral genetic diversity, scientists aim to preserve corals in the hopes that they can be reintroduced to reefs. Existing cryopreservation techniques for coral conservation require collecting coral sperm and larvae during spawning events that occur only once a year, while isochoric vitrification of tissue would allow freezing of coral year-round.

Currently, Rubinsky is also exploring the possibility of applying isochoric vitrification techniques to organ transplantation, hoping to extend the shelf life for organ donations that currently are only viable outside of the body for a few hours. Pushing these limits with isochoric vitrification techniques would enable organs to stay viable for longer, allowing for more time to find a match, potentially saving lives.