Swapping ‘heavy’ water for regular water should allow scientists to use transmission electron microscopy (TEM) to observe biological materials in water using for longer before damage occurs.

Although a powerful technology for studying molecules in dry or frozen states, the high-energy electron beams used in TEM to probe molecules in water generate an electric charge that breaks chemical bonds and damage specimens.

Now, a team of scientists at the Institute for Basic Sciences has used a form of water called heavy water (D₂O), which contains deuterium instead of hydrogen, when using TEM to observe fragile biological molecules. Furthermore, they encapsulated the samples in a tiny pocket between two graphene sheets to protect them from the electrical charge produced by TEM.

The scientists found that organic molecules dissolved in D₂O lasted 2 to 5 times longer than those dissolved in water.