A new approach keeps fluids from freezing at very low temperatures

<pre>A new approach keeps fluids from freezing at very low temperatures

Scientists from the Massachusetts Medical Technology Center (MGH-CEM) have developed a simple method of maintaining water and solutions based on water in a liquid state at temperatures well below the usual “freezing point” for very long periods of time. While they managed to do this with a volume of just a few ounces, their approach, described in Nature Communications, could once provide a safe, long-term preservation of blood cells, tissues and organs, and improve food safety.

“Water and Others aqueous solutions in the volumes that we meet every day, usually freeze when cooled below the freezing point of 0 degrees Celsius, “says Burke Usta, Ph.D. from MGH-CEM, co-author of the work. “Our approach, which we called” deep hypothermia, “is to cover the surface of such a liquid with a solution that does not mix with water, like mineral oil, to block the interaction between water and air. This surprisingly simple, practical and inexpensive approach of supercooling liquids for long periods can open up many methods of preserving food and medicine, and will also allow the carrying out of fundamental experiments that were not previously available. “

Is it possible to freeze organs for a long time?

In In most real environments, water and aqueous solutions start to freeze when the temperature reaches a level below zero, with ice crystals being formed arbitrarily where the liquids come into contact with air or various impurities in solution. The supercooling that allows the liquid to be maintained at a low temperature without crystallization can only be carried out with small volumes and for short periods of time using high-pressure equipment that is expensive and can damage tissues or other biological materials.

A decrease in the temperature of any biological material – in the process, for example, cold storage of perishable products and organs for transplantation – slow down metabolic and other reactions. Subcooling prolongs this slowing of metabolism without damage caused by the crystallization of ice. Scientists have found that sealing a surface of a small (1 ml) water sample with a hydrocarbon-based oil, such as mineral, olive or paraffin oil, can suppress ice formation at temperatures as low as -13 degrees during the week. During experiments with more complex oils and simple hydrocarbons, such as alcohols and alkanes, they managed to store 1 ml of water samples and cell suspensions supercooled to -20 degrees for 100 days and 100 ml samples for a week.

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