Shedding New Light

“We found a new way that the universe works that we didn’t understand before,” says Matthew Liptak, chemist and co-head of an exciting new study, published in Nature Chemistry. Scientists from University of Vermont and Dartmouth College have discovered a new way that molecules light up.

Credit: University of Vermont

The organic light sources are called molecular rotors, naturally-occurring proteins with an elongated, twisted structure. Now, the proteins naturally vibrate, and when placed in a thick solution with high viscosity, it’s expected that the vibration will be limited. “[They] can sense viscosity within a cell,” Liptak says.

What makes this discovery profound is that the molecular rotors’ behavior totally defies a long-standing rule of chemistry called Kasha’s Rule. In 1950, the famed chemist of the same name established that a luminescent molecule will emit light at a constant intensity, regardless of the energy directed to it. In other words, a molecule subjected to higher energy would just become hotter, not any brighter. But this isn’t the case with Liptak and his team’s discovery: the more that the energy of the rotors are suppressed, the brighter and more energetic is the luminescence observed. The researchers coined this behavior as Suppression of Kasha’s Rule (SOKR).

Shedding Light on Future Discoveries

“The compound we found is very bright, and due to its viscosity sensitivity, may have a multitude of applications,” says Morgan Cousins, co-author on the new study. This new discovery may be the light that applications like cellular study need. The differences in viscosity, or the “thickness” of liquid, of subcellular components could be harnessed to reveal previously unseen behavior. Currently, the molecules are not safe for human use, but the scientists are currently hunting for similar bio-compatible compounds. As explains, this discovery could have some applications in medical science, especially diagnostics. Should bio-compatible organisms be found, they can be incorporated with medical dyes to conduct testing in ways never before conceived.

It’s clear that the universe is still bursting to the seams of undiscovered brilliance. What we’ve solidified as a natural rule before could still so easily be broken—a curious little molecule lighting up our perspective showed us just that.

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