About a third of all deaths in the U.S. could be prevented or substantially delayed by organ transplantation, according to a 2015 report from the U.S. military. The main bottleneck is that there is no practical way to preserve organs for more than a few hours. If you try to freeze a whole organ, water within and between cells forms ice crystals that cause the cells to rupture.
Researchers are currently hunting for chemical solutions that might prevent these ice crystals from forming, thus allowing organs to be safely banked at subzero temperatures for days or even longer.
Carlos Baiz, assistant professor of chemistry at the University of Texas at Austin, is examining one such "cryoprotectant", called dimethyl sulfoxide (DMSO). Earlier research showed that DMSO does prevent water from forming ice crystals, but it's toxic to cells. Baiz is trying to understand what makes DMSO toxic and how its toxicity is altered when combined with other substances. Ultimately, he'd like to find a substance or combination of substances with the benefits of DMSO, but not the drawbacks.
He and his team used a technique called infrared absorption spectroscopy to study how DMSO and water interact in a solution, specifically what kinds of hydrogen bonds form between the two substances. Baiz believes those hydrogen bonds might hold the key to understanding how DMSO damages cells.
Reporting this week in the journal Angewandte Chemie, he and his team found very different hydrogen bonding interactions than those predicted by computer models. Their empirical findings will help scientists develop molecular models and perhaps make better predictions about what substances could prevent ice crystal formation without being toxic to cells.
Interestingly, earlier research has shown that when you combine DMSO with formamide, together they are less toxic to cells than either by themselves, yet still too toxic to use in humans. Baiz plans to repeat his experiment, but this time including formamide in a range of concentrations to better understand how all three (DMSO, formamide and water) interact.
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