Researchers from MIT and Harvard Medical School have developed a colour-changing tattoo that responds to changes in the body, such as blood sugar and sodium levels, and could be a revolutionary new way to monitor health. The project, called DermalAbyss, uses a tattoo made from a liquid infused with biosensors instead of traditional ink, turning human skin into an "interactive display." The team has developed three different kinds of inks that change colour in response to changes in interstitial fluid — the liquid that flows around and between our cells, and comprises 16 percent of our body weight. So far, the most interesting of the three inks can measure glucose levels, which change colour from blue to brown as blood sugar levels rise and could be used diabetics, who currently have to rely on blood tests throughout the day to monitor their glucose levels. To find out more go to DermalAbyss: Possibilities of Biosensors as a Tattooed Interface.