Key takeaways

 Researchers have developed new tattoo inks that change color in response to diverse signals.

 The group’s prototypes include tattoos that only appear when they’re exposed to sunlight and that turn on and off at certain temperatures.

 Once they undergo safety testing, such tattoos also could alert people to changes in their blood chemistry or help doctors diagnose illness.

When a pair of tourists hiking the Alps stumbled across the frozen remains of the mummy Ötzi in 1991 they also, unknowingly, discovered the oldest known examples of tattoos in history. The 5,300-year-old body, more famously known as the Iceman, has 61 tattoos arranged in patterns of straight lines scratched across his skin.

What amazes CU Boulder chemist Carson Bruns about those dyes, however, isn’t their age. It’s what they’re made of. 

“They’re made of the same stuff that our tattoos are made of,” said Bruns, of CU Boulder’s ATLAS Institute. “It blows my mind that we haven’t updated this technology in so long.”

Bruns wants to change that. He’s designing a line of “tech tattoos” that don’t just look cool: They might also help to keep you healthy one day—alerting people when they run a fever or even allowing doctors to diagnose medical conditions without expensive blood tests.

“When you think about what a tattoo is, it’s just a bunch of particles that sit in your skin,” said Bruns, also an assistant professor in the Department of Mechanical Engineering. “Our thought is: What if we use nanotechnology to give these particles some function?”

The pursuit of tattoos that do more merges two of Bruns’ passions: nanotechnology and art. During his free time, the scientist paints and has even dabbled in tattooing skin himself.

It blows my mind that we haven’t updated this technology in so long.” –Carson Bruns

His first tech tattoo inks include “solar freckles,” or tattoos that are only visible when exposed to sunlight. He said that such body art might one day give people a heads up when their sunscreen has worn off. And he has developed an ink that turns on and off at different temperatures—potentially allowing people to carry around their own, built-in thermometers.

You may not see these designs in your local tattoo parlor for several years—they will need to undergo rigorous safety testing first.

But they also represent something new for the age-old craft of body art: tattoos that would make Ötzi sit up and take notice.

Originally published Dec. 4, 2018

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