Researchers Develop the World’s Smallest Programmable DNA Nanothermometer

A programmable DNA thermometer, 20,000 times smaller than a strand of human hair, has been developed by researchers at the University of Montreal. This scientific discovery was recently reported in Nano Letters, and is likely to help the understanding of both human designed and natural nanotechnologies by carrying out temperature measurement at the nanoscale.

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The fact that the DNA molecules encoding DNA molecules are capable of unfolding when heated was discovered 60 years ago.

In recent years, biochemists also discovered that biomolecules such as proteins or RNA (a molecule similar to DNA) are employed as nanothermometers in living organisms and report temperature variation by folding or unfolding. Inspired by those natural nanothermometers, which are typically 20,000x smaller than a human hair, we have created various DNA structures that can fold and unfold at specifically defined temperatures.

Prof. Alexis Vallée-Bélisle, University of Montreal

One of the key benefits of using DNA to develop molecular thermometers is that DNA chemistry is reasonably programmable and simple. "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," explains David Gareau, first author of the study. "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.

Arnaud Desrosiers, University of Montreal

All of these nanoscale thermometers make room for further inventions in the growing field of nanotechnology, and may also improve the understanding of molecular biology.

There are still many unanswered questions in biology. For example, we know that the temperature inside the human body is maintained at 37° C, but we have no idea whether there is a large temperature variation at the nanoscale inside each individual cell.

Prof. Alexis Vallée-Bélisle, University of Montreal

The team is currently concentrating on determining whether nanomotors and nanomachines naturally developed by nature over millions of years of evolution also overheat when working at high rate.

In the near future, we also envision that these DNA-based nanothermometers may be implemented in electronic-based devices in order to monitor local temperature variation at the nanoscale.

Prof. Alexis Vallée-Bélisle, University of Montreal

This research was supported by the Natural Sciences and Engineering Research Council of Canada. On April 27th 2016, Alexis Vallée-Bélisle of the University of Montreal's Department of Chemistry and Department of Biochemistry published "Programmable, quantitative, DNA-base nanothermometers," in Nano Letters.

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