Chemists in Canada have successfully built a programmable DNA thermometer – the smallest in the world at 20,000 times tinier than the human hair.

This breakthrough, harnessing man-made nanotechnology can potentially enable the measurement of temperatures at the nanoscale.

Researchers found over six decades earlier that DNA molecules which encode genetic information can unfold with heating. Recently, biochemistry experts also discovered that RNA and other biomolecules are used in nanothermometers in living creatures, indicating changes in temperature when they fold or unfold.

Such natural nanothermometers inspired the team from University of Montreal to create different DNA structures to fold and unfold at designated temperatures.

DNA proved beneficial in creating molecular thermometers as its chemistry is deemed simple as well as programmable – it is, for instance, made up of four nucleotides: nucleotide A for weakly binding to nucleotide T, and nucleotide C strongly binding to nucleotide G. Following these simple rules led to the success of the experiment.

“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 study author Arnaud Desrosiers.

DNA thermometers are seen to help fill gaps in molecular biology. According to senior author and professor Alexis Vallée-Bélisle, while human body temperature is kept at 37 degrees Celsius (98.6 Fahrenheit), it is unknown if a huge temperature variation is taking place at the nanoscale inside individual cells.

The team is foreseeing the thermometer’s role in electronic devices for tracking local, nanoscale-level temperature changes. They are also looking to study the potential overheating of natural nanomachines when they function at a high rate.

The findings are published in the Nano Letters journal.

The nanotechnology field itself is filled with exciting developments, such as the creation of a nanotechnology coating that could control the spread of potentially fatal, hard-to-kill superbugs or antibiotic-resistant microorganisms.

The discovery likely allows ordinary items such as door handles, telephones, and smartphones to be protected against these bacteria, which are feared to kill around 10 million individuals worldwide by 2050.

Photo: Miki Yoshihito | Flickr