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Researchers Use DNA to Create World’s Smallest Thermometer

A team of scientists at the University of Montreal, Canada, has created a DNA-based nanothermometer that is 20,000 times smaller than a human hair.

Scientists in Canada have developed DNA-based thermometers that allow to measure temperature at the nanoscale. Image credit: Kotkoa.

Scientists in Canada have developed DNA-based thermometers that allow to measure temperature at the nanoscale. Image credit: Kotkoa.

More than six decades ago, biochemists discovered that the DNA molecules that encode our genetic information can unfold when heated.

In recent years, they also discovered that biomolecules such as proteins or RNA are employed as nanothermometers in living organisms and report temperature variation by folding or unfolding.

“Inspired by those natural nanothermometers, which are typically 20,000 times smaller than a human hair, we have created various DNA structures that can fold and unfold at specifically defined temperatures,” said lead author Prof. Alexis Vallée-Bélisle, from the Laboratory of Biosensors and Nanomachines and the Department of Biochemistry and Molecular Medicine at the University of Montreal.

One of the main advantages of using DNA to engineer molecular thermometers is that DNA chemistry is relatively simple and programmable.

“DNA is made from four different monomer molecules called nucleotides: nucleotide A binds weakly to nucleotide T, whereas nucleotide C binds strongly to nucleotide G,” said co-author Dr. David Gareau from the University of Montreal’s Laboratory of Biosensors and Nanomachines.

“Using these simple design rules we are able to create DNA structures that fold and unfold at a specifically desired temperature.”

“By adding optical reporters to these DNA structures, we can therefore create 5 nm-wide thermometers that produce an easily detectable signal as a function of temperature,” said co-author Dr. Arnaud Desrosiers.

These nanothermometers open many avenues in the emerging field of nanotechnology, and may even help researchers to better understand molecular biology.

“There are still many unanswered questions in biology,” said Prof. Vallée-Bélisle.

“For example, we know that the temperature inside the human body is maintained at 98.6 degrees Fahrenheit (37 degrees Celsius), but we have no idea whether there is a large temperature variation at the nanoscale inside each individual cell.”

This research was published online April 8, 2016 in the journal Nano Letters.

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David Gareau et al. Programmable Quantitative DNA Nanothermometers. Nano Lett., published online April 8, 2016; doi: 10.1021/acs.nanolett.6b00156