The use of color-changing dye can potentially detect changes in each of the three biomarkers — glucose, albumin, or pH — in the body’s interstitial fluid, which transports oxygen and glucose between cells. The albumin sensor is a yellow dye that turns green in the presence of albumin, the changing concentration of glucose causes the sensor’s pigment to go from yellow to dark green, and the pH sensors ranges from yellow to blue at normal levels, researchers said. So far, the tattoos have only been tested on pig skin and are not ready for human use, according to the researchers....