Biosensor tattoo monitors sweat to gauge physical exertion

Wearable electronics like the FitBit (see disclosure) allow people to track physical activity like never before. But accelerometers and altimeters can only tell the wearer so much.
Researchers at the University of California-San Diego have developed a sensor that is applied to the skin like a temporary tattoo. Once in place, it monitors chemicals in the wearer’s sweat to gauge physical exertion. They published their results in Analytical Chemistry this month (subscription required).
The body produces an acid called lactate during intense physical activity. If you’ve ever felt your muscles burn while running, that was lactate building up. The more it builds up, the more your body releases it in sweat.
Right now, the best way to monitor for lactate involves a finger prick. It is commonly used for athletes engaging in high-intensity activities, but they have to stop regularly to collect a blood sample. Researchers have developed noninvasive testing techniques like a patch that collects sweat, but the patch still has to be brought to a lab for analysis.
The tattoo is both noninvasive and immediate. The sensor is screen-printed onto the adhesive part and flexible enough to withstand repeated movement.
The UC-San Diego researchers now want to make the tattoo’s electrical components smaller and improve how data is processed and wirelessly transmitted. They also want to test the tattoo with a broader range of people. While they envision it being an important tool for athletes and military personel, it could also be useful for the general public. They founded Electrozyme to begin commercializing the tattoos.
Temporary tattoos are emerging as options to monitor many different areas of health. In 2011, University of Illinois researchers developed a tattoo that measures muscle and nerve activity. It can also be a applied to the vocal cords to sense speech. Since then, they’ve developed way to directly print sensor electronics onto the skin, making them thinner and more comfortable.  Motorola also showcased a temporary tattoo this year that can be used as a physical password. As these tiny sensors become more stable, maybe we will see them begin to be integrated into wearable electronics.
Disclosure: Fitbit is backed by True Ventures, a venture capital firm that is an investor in the parent company of this blog, GigaOM. Om Malik, founder of GigaOM, is also a venture partner at True.