What is Cryopreservation?
Do you remember watching science fiction movies like “Avatar” and “Interstellar,” in which the characters were put to sleep in futuristic pods, allowing self-preservation for many years? While this concept sounds absurdly fictional, it’s actually not so distant from reality. Known as cryopreservation, this process preserves the structure of biological material, like cells and tissues, by cooling them down to very low temperatures.
You may think that accomplishing such a mindblowing feat is impossible. After all, how could the brain possibly survive such conditions? However, scientists have been attempting to turn this fascinating concept into a reality.
Until now, the main challenge with freezing brain tissues was the cooling and warming process. When frozen, the sample typically sustains damage caused by the formation of ice crystals, which results in the displacement or penetration of the brain tissue’s nanostructure, thus disrupting important cellular processes. It also leads to osmotic injury, which is the rate of water transport, such as rapid rehydration.
Simply put, so far, traditional freezing methods have failed to preserve neural structure and function. This caused scientists and researchers alike to hit a dead end in the research process. However, just like navigating a maze, innovators have discovered a new path that allows them to bypass this “dead-end:” vitrification.
Above: A technician withdrawing deep-frozen cells for in vitro culture at a laboratory of a German pharmaceutical company. Image courtesy of Britannica.
What is Vitrification?
Vitrification is a method that preserves the tissue sample in a state similar to that of glass. By cooling the liquids at a fast rate, it prevents the formation of destructive ice crystals.
In a study conducted by Alexander German, a neurologist at the University of Erlangen–Nuremberg in Germany, and his colleagues, the researchers tested to see if the brain could regain function after a complete pause of molecular mobility (essentially, in a frozen/vitreous state). They first tested their hypothesis on some slices of mouse brains, specifically the hippocampus, which is responsible for memory and spatial navigation. They treated these brain slices in a solution of cryopreservation chemicals before using liquid nitrogen to cool them down to -196º C. The researchers kept these samples in a freezer for up to a week.
Did their method work? Well, after thawing the samples, the scientists were able to observe that the tissues retained their core functions, including synaptic transmission (communication) and neuronal excitability (response to electrical stimuli). However, the most important result for future studies is long-term potentiation, which is key in maintaining memory and learning abilities.
Above: Recovery of synaptic functions after slice vitrification and rewarming. Image courtesy of PNAS.
Future Potential
Now that we have established that such important cognitive functions can survive cryopreservation, what does this mean for the future? This new method of preservation would allow neural tissue to be transported to various locations, even allowing its use across time. This could help improve reproducibility, allowing researchers to work with consistent data, and potentially reduce the use of animals in research. Second, cryopreservation could be useful for structural studies, allowing the tissue to be analyzed without causing any changes in its structure.
However, the ultimate goal is cryomedicine, which would improve the preservation of organs and other complex tissues to be used for transplantation. Vitrification may also allow for new methods in protecting the nervous system from disease or other injuries. While there is still a long way to go in the path towards fully developing cryopreservation as a means to prevent aging or achieve immortality, what we have accomplished so far is still very exciting and has much potential for further research. Who knows…we just might make the trip to Pandora a reality.
Written by Aryahi Dhar, this article was selected as a winner of our 2026 High School Science Communication Challenge. From Cary, NC, Dhar is a student at Enloe High School.