Tattoos can hold a lot of different meanings. Throughout history, they've been used to communicate status, culture, identity and nowadays merely for fashion. But in the future they could also have functional, medical benefits. Scientists in Germany have developed colour-changing tattoos that could allow diabetic patients and people with other conditions to monitor their health simply by looking at their skin.
The researchers used injectable pigments that change colour when pH, glucose or albumin levels change in the body. The development could allow art and science to be combined, blending tattoo artistry with medical advances. Reddit is abuzz with talk about the possibilities, but for now some significant hurdles remain (if you're looking for inspiration, see our pick of the best free tattoo fonts).
Chemical engineer Ali Yetisen and a team at the Technical University of Munich first described their functional colour-changing intradermal tattoos in a research article back in 2019. They made tattoos that adapt to changing levels of pH, glucose and albumin in the blood, with the idea being to allow patients to track their own health without needing any extra device. The idea has been picked up on the Reddit, with many wanting to know we'll start to see the technology used in practice.
The researchers chose to study three biomarkers that play big roles in predicting changes in our bodies. Monitoring glucose levels is vital for diabetics while pH changes can signal kidney and lung problems and albumin levels can identify kidney, liver and heart issues. Each of the three tattoos used a different pigment that was affected by changes in the biomarker, with the one used to monitor glucose starting yellow and turning a dark green if glucose levels rose.
The levels of concentration could be assessed simply by looking at a photo of the tattoo, potentially saving a lot of time in communication between doctors and patients. Another potential benefit is that in theory, the tattoos could be applied in any form, allowing the patient to choose a tattoo that matched their taste, although it would probably have to be fairly simple and located somewhere they can easily see it.
People commenting on Reddit's r/BeAmazed channel are, well, amazed. "just met someone that has a massive amount of allergies and physical issues, and simple things like this would make their life sooo much easier," one person wrote this week. "As someone who was diagnosed with end stage kidney disease this summer, being able to monitor albumin without a blood test would be a huge benefit," another person added. Not everyone is convinced about the pigments used though. "They can start working on making it not look like mold!" one person suggested.
Several issues mean that it will be some time before the technique becomes a practical reality, though. For one, the researchers only tested the technique on pig skin. Secondly, only one the tattoo to monitor pH was reversible. Even more problematically, only the pH sensor can shift repeatedly. The albumin and glucose tattoos can only change once, meaning that once they've changed, you'd have a permanent tattoo that no longer has any function.
However, the scientists hope to find ways to make all the tattoos reversible using synthetic receptors. They also believe it might be possible to eventually create tattoos that can monitor levels of hydration, electrolytes and more. This will presumably be at least several years away, but you might want to start thinking about ideas with our pick of the best tattoo designs.