Alexis Vallée-Bélisle, David Gareau, and Arnaud Desrosiers, Université de Montréal, Québec, Canada, have designed a thermometer which is 5 nm thick and capable of measuring temperature variations of 0.05 °C.

If DNA is heated, it unfolds a little bit. Through targeted structural modifications of the base sequence or via addition of inexpensive DNA stabilizers, the researchers have produced DNA molecules whose length increases linearly and reliably in the temperature range between 30 and 85 °C. By measuring the length by means of optical sensors, this reveals the temperature of the DNA solution.

The researchers tested the nanothermometer in a polymerase chain reactions (PCR) device and demonstrated the fast response time (ms–s), reversibility, robustness, and efficiency of these programmable DNA thermometers. According to the researchers they are suitable for real-time temperature monitoring in vicinity of enzymes, in vivo or in nano- or microfluidic devices where local temperatures at nanoscale may be important.

• Programmable Quantitative DNA Nanothermometers,
  David Gareau, Arnaud Desrosiers, Alexis Vallée-Bélisle,
  Nano Lett. 2016.
  DOI: 10.1021/acs.nanolett.6b00156