Freezing is regarded as the best technique for long-term preserving of food, organs and even living organisms. As temperature drops, reactions slow down and microbial activity is reduced to a minimum. Although it is the technique of choice when it comes to preservation, cryopreservation poses several challenges. Water is the most common component of cells in living organisms and when temperature drops and water is turned into ice. That same component that is essential to live becomes deleterious. Water crystallization upon freezing disrupts cells in a way that is in many cases irrecoverable upon thawing, originating cell dead in living organism or organs. There are several solutions to minimize these effects such as the use of specific freeze time gradients to control the number and size of intracellular ice crystals or the use of cryoprotectants, promoting the amorphization of water thus avoiding in part or completely the crystallization process. The solution for more complex systems is the use of cryopreservant agents, however the need for high concentrations of cryopreservants are sometimes needed arising toxicity issues(1). Although cryopreservation is a high value market it lacks efficient solutions. The examples of implementation of this technique in industry are mainly in embryo, sperm and stem cell storage where a large number of cell dead upon thawing is acceptable(2).
The inspiration for the solution proposed in CryoDES comes from nature itself. Since the beginning of times that mankind has been mimicking nature in order to develop new technologies, products and solutions for everyday problems. This is especially true for pharmaceutic and food industries in the search for new, safer and better drugs and food additives. The same principle can be applied to cryopreservation. There are numerous examples of animals that survive in extreme temperature environments. Recent findings have reported the reason some living beings are able to withstand the huge thermal amplitude from winter to summer in their natural habitats. They are able to produce metabolites, which act as cryoprotectants, decreasing deeply the crystallization temperature of water, avoiding cell disrupture by the mechanical stresses caused by ice crystals and overcoming osmotic effects. These metabolites are mostly sugars, organic acids, choline derivatives or urea. These compounds have been defined as constituents from Natural Deep Eutectic Solvents (NADES) and present great potential for the development of cryoprotective agents. This will be the major focus of the workplan proposed. The interdisciplinary nature of the proposal couples biochemistry, physical-chemistry and thermodynamics to design a strategy able to overcome the drawbacks of cryopreservation by vitrification.