Smart tattoo ink changes colour for dehydration, blood sugar

Imagine a tattoo that changed colour if your blood sugar levels rose or if you were dehydrated?

Skin art will soon be functional thanks to some clever researchers at Harvard Medical School and MIT.

The researchers have developed smart tattoo ink capable of monitoring health by changing colour to tell an athlete if she is dehydrated or a diabetic if his blood sugar rises.

The work paired biosensitive inks developed at Harvard with traditional tattoo artistry as a way to overcome some of the limitations of current biomedical monitoring devices.

“We were thinking: new technologies, what is the next generation after wearables?” said researcher Ali Yetisen. “And so we came up with the idea that we could incorporate biosensors in the skin.”

A drawback of current wearable monitoring devices is that they don’t seamlessly integrate with the body, Yetisen said. Short battery life is a concern and so is the need for wireless connectivity, neither of which is an issue with the simple, colour-based interface of biosensitive tattoo ink.

“We wanted to go beyond what is available through wearables today,” Yetisen said.

Fellow researcher Nan Jiang said the project, ‘Dermal Abyss’, was conducted as a proof of concept, and that further refinements — stabilising ink so designs don’t fade or diffuse into surrounding tissue — would be needed for a medical product.

The Dermal Abyss tattoo inks change colour according to the chemistry of the body’s interstitial fluid, which can be used as a surrogate for constituents of the blood. Inks developed so far change from green to brown as glucose concentration increases. The team also developed a green ink, viewable under blue light, that grows more intense as sodium concentration rises, an indication of dehydration. Researchers tattooed the inks onto segments of pig skin and noted how they changed colour or intensity in response to different biomarkers.

Jiang and Yetisen said that once the bugs are worked out, the applications for biologically sensitive ink are fairly broad. Inks, Yetisen said, could be incorporated into long-lasting tattoos for chronic conditions or into temporary designs for shorter-duration monitoring. Ink can even be invisible, Yetisen said, readable under only particular kinds of light. That light could come from something as ubiquitous as a smartphone.

Yetisen has already developed an app that can analyse a picture of a sensor and provide quantitative diagnostic results. While patients are an obvious potential market, Yetisen said the technology could be used in astronauts, for whom continuous health monitoring is desirable.

Wearable tattoo progressively changing colour to monitor dehydration and blood sugar. Image credits: ©Harvard Medical School

Originally published here.