The world’s smallest thermometer is 20,000 times smaller than a single human hair. Oh, and it’s made out of genetic material.

Researchers from the Laboratory of Biosensors and Nanomachines at the University of Montreal report that they’ve created a thermometer out of DNA in a recent article in the journal Nano Letters.

DNA molecules unfold in response to heat, so the researchers created DNA structures that would unfold and fold at very specific temperatures. Thus, the structure of the DNA strands can reveal data about the temperature. The thermometer has a range of 122°F, and when the temperature reaches certain levels, the tiny thermometer sends out light-based signals.

The finding could one day be used to measure temperature in nanotechnology or even to monitor changes in temperature between individual cells in the human body.

[h/t Gizmag]