DNA strings turned into world's tiniest thermometer

Now, you will be able to take a temperature in a hard-to-reach spot as a team of researchers has created the world's smallest thermometer from DNA.

The University of Montreal researchers created a programmable DNA thermometer that is 20,000x smaller than a human hair. This scientific advance may significantly aid our understanding of natural and human designed nanotechnologies by enabling to measure temperature at the nanoscale.

Over 60 years ago, researchers 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," said senior author Alexis Vallee-Belisle.

Vallee-Belisle noted, "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."

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 first author 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 co-author Arnaud Desrosiers.

The study is reported in the journal Nano Letters.