As reported on April 27, the world's smallest thermometer has been created by researchers. The most interesting feature of this thermometer is that it is made out of DNA. This DNA made thermometer can be used to check the temperature of even the smallest human cells.

The research was published online in the journal Nano Letters on April 8. According to Sci News, this nano thermometer is 20,000 times smaller than one human hair. Researchers from the Montreal University developed this tiny thermometer based on the way the RNA (a long-chain molecule similar to DNA) folds and unfolds in varying temperatures. The team carefully customized the thermometer design based on the unique DNA structure.

DNA is made up of four different nucleotides (monomer molecules), wherein the nucleotide A binds to nucleotide T weakly while nucleotide C binds to nucleotide G strongly. The relatively simple and programmable DNA chemistry served as an advantage in making molecular thermometers. The result of this research is a 5-nanometer-wide structure that can be used to determine temperatures.

Several decades ago, it was discovered that DNA molecules can unfold when heated. In the recent years, it was also found that RNA or proteins are a kind of nano thermometers in living organisms, as they gave information about temperature variation by folding or unfolding. This inspired researchers to use DNA molecule to create the world's smallest thermometer, and they made extended thermometers that respond up to 50 °C temperature range. Considering the human body temperature maintained at 37 °C constant temperature, this thermometer temperature range is said to be very much enough.

The research team claims that these minute temperature probes can help understand what happens inside the human body more accurately. As per Professor Vallée-Bélisle, it is yet to be found out whether a large temperature variation takes place inside each individual cell at the nano scale level.