Medical sensor is temporary skin tattoo

A medical sensor that attaches to the skin like a temporary tattoo could help doctors detect metabolic problems, researchers at the University of Toronto say. The sensor that comes in a thin, flexible package shaped like a smiley face could also help coaches fine-tune athlete's training routines, they said. The sensor can detect changes in the skin's pH levels in response to metabolic stress from exertion during exercise, but can also give clues to underlying metabolic diseases such as Addison's disease, a university release said Monday Existing devices to accomplish this can be bulky or hard to keep adhered to sweating skin, researchers said, which led them to develop a sensor using standard screen printing techniques and commercially available transfer tattoo paper. "We wanted a design that could conceal the electrodes," said doctoral candidate Vinci Hung, who helped create the new sensor. "We also wanted to showcase the variety of designs that can be accomplished with this fabrication technique." In the "Happy face" sensor, the "eyes" function as the working and reference electrodes while the "ears" are contacts for a measurement device to connect to.