A team of chemists may have accomplished a phenomenal feat, as they've built the world's smallest thermometer with the help of DNA.
Researchers discovered over 60 years ago that DNA molecules that encode our genetic information can unfold when heated. Recently, scientists have also found that biomolecules, such as proteins or RNA, are used as nanothermometers in living organisms and report temperature variation by folding or unfolding.
In the latest study, the researchers decided to take a look at the features of DNA in order to create their own thermometer.
"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 David Gareau of the University of Montreal, first author of the study. "Using these simple design rules we were able to create DNA structures that fold and unfold at a specifically desired temperature."
The researchers not only created DNA structures, but they also added optical reporters to the structures. This, in turn, helped the scientists create thermometers that were a mere five nanometers wide. These tiny thermometers are about 20,000 times smaller than a human hair and can produce an easily detectable signal as a function of temperature.
While creating tiny thermometers is interesting, one may wonder exactly what they could be used for. In reality, these nanoscale thermometers actually open up many exciting avenues in the emerging field of nanotechnology.
So what avenues do they open? They could help us better understand molecular biology.
"There are still many unanswered questions in biology," said Alexis Vallee-Belisle, senior author of the new study. "For example, we know that the temperature inside the human body is maintained at 37 degrees Celsius, but we have no idea whether there is a large temperature variation at the nanoscale inside each individual cell."
One of the priorities the research team is to figure out whether nanomachines and nanomotors developed by nature over millions of years of evolution also overheat when they function at a high rate. This means that the tiny thermometers could be extremely useful when it comes to monitoring local temperature variation at the nanoscale.
The findings were published in the April 8 issue of the journal Nano Letters.
