These Color Changing Tattoos Could Save Lives

For millions who struggle with blood sugar issues or dehydration, tracking those changes can be difficult. Harvard researchers partnered with MIT engineers to create a tattoo that could tell people exactly what's wrong. 

The engineers developed biosensitive tattoo inks that solve a lot of the problems of current wearable devices. Ali Yetisen, a postdoctoral fellow at Massachusettes General Hospital, said the idea came from looking into a future beyond modern wearables. Short battery life and wireless connectivity to a device hinder those who need constant monitoring services. 

Nan Jiang is a postdoc fellow at Harvard Medical School and called the project "Dermal Abyss." The proof-of-concept inks change colors based on the body's interstitial fluid. According to researchers, interstitial fluid doubles as an indicator for internal measures. The team created different inks for different issues. Green inks get more intense as the body's sodium concentration increases. That indicates dehydration. A green ink also changes to brown as glucose concentrations rise. 

"The purpose of the work is to light the imagination of biotechnologists and stimulate public support for such efforts," Jiang said. "These questions of how technology impacts our lives must be considered as carefully as the design of the molecular sensors patients may someday carry embedded in their skin."

Both Jiang and Yetisen hoped the inks could have a really broad range of applications. Yetisen even noted that the tattoo ink could be adapted for long-lasting wear on people with chronic conditions. They're also working on tattoo ink that would be invisible except for under particular kinds of light. 

The biosensor ink would be visible and give wearers a general understanding of their body's warning signs. However, Yetisen developed an additional app to analyze a picture of the sensor and provide comprehensive diagnostics. The ink could even one day be used on astronauts who consistently need monitoring. 

Jiang also noted that the project could bring forth discussion about the ethics of visible wearables. For example, where is the line drawn regarding the safety of medical records when someone wishes to have their information literally tattooed on their skin?