Anyone who grew up in the 1990s might remember the short-lived craze for colour-changing T-shirts, which revealed the wearer's hot and sweaty armpits to the world. But while the clothing may have fallen out of fashion, similar technology is now proving to have surprising new applications. Using chemicals that change colour in the presence of water, researchers have developed a highly precise sensor that can reveal the traces of sweat left by human pores. These 'maps' show the water left by sweat pores in three different prints from the same finger of one person (coloured red, yellow and blue), overlaid to show the accuracy of the technique. As well as potentially being useful for analysing fingerprints, the technique could also help to diagnose diseases where the sweat pores stop working – a condition known as hypohidrosis – which can be extremely dangerous and lead to heat stroke or even death.
Written by Kat Arney