MIT and Harvard researchers have created color-changing tattoos that could, in the future, track your pH, glucose, and sodium levels. DermalAbyss replaces typical tattoo ink with biosensors, which respond to changes in the skin’s interstitial fluid that surrounds tissue cells. It’s currently a proof-of-concept, and has only been tested on pig skin. But researchers envision that one day, diabetics could get a biosensor tattoo to monitor their glucose levels without daily finger prick tests. Watch our video to see how the biosensor tattoo works.