A team of scientists at the University of Montreal, Canada, have successfully turned a programmable DNA into a thermometer that is 20,000 times smaller than a human hair.  This scientific advance – world’s smallest thermometer may significantly aid our understanding of natural and human-designed nanotechnologies by enabling to measure the temperature at the nanoscale.

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

“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,” Prof. Alexis Vallee-Belisle, a researcher from the University of Montreal, said in a news release.

“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,” Vallee-Belisle noted.

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,” explained co-author Dr. David Gareau. “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,” added Arnaud Desrosiers, co-author of this study.

“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,” Vallee-Belisle said.

These nanoscale thermometers open many exciting avenues in the emerging field of nanotechnology, and may even help us to better understand molecular biology.

The study was published online in the journal Nano Letters.