Researchers at Tokyo University say that they have developed a micro-thin thermal sensor that can be attached directly to the skin.

Embedded in an ultra-fine film, this device is designed to measure temperatures between 25 and 50° Celsius — a range that includes that of the human body.

The findings (made in collaboration with the University of Texas) were published in the Proceedings of the National Academy of Sciences journal.

Professor Takao Someya, who heads a research team at the University of Tokyo, said that the sensors — made of graphite and a semi-crystalline acrylate polymer — are about one quarter the thickness of a human hair. “They can be attached to adhesive plasters and used to monitor body temperature.

For example, a plaster applied directly to a wound or after surgery could warn of infection by detecting local changes in temperature due to inflammation.

By putting it on the skin of a baby, you can easily check the infant’s body temperature. Alternatively, measuring changes in body temperature over a large area could help in the development of more comfortable sports clothing.”

He added that the device could be commercialised for practical use in as little as three years.

The team tested the sensor by placing it directly on the lung of a rat. Research associate Tomoyuki Yokota said: “The device successfully measured cyclic changes in lung temperature of just 0.1° Celsius as the animal breathed.”