Nowadays, tattoos have gradually become a fashion, even art. But if I tell you, in addition to good looks, your tattoo can monitor blood sugar, heart, kidney, and other physical data. Do you believe it?
Perhaps you, like me, would think of the "Female Jobs" Elizabeth Holmes, a Silicon Valley scam that can complete more than 300 blood tests by fingertips.
But the health monitoring device in the form of tattoos is no longer a sci-fi concept, but a achievable thing. Replacing existing wearables, even smartphones, with electronic skin is the direction that many scientists are working on, and there have been some exciting breakthroughs.
How do you monitor health from changes in tattoo color?
Recently, German scientists have developed a special "tattoo ink" that changes color with changes in glucose, albumin, and pH in the human body. These changes in color allow patients and doctors to monitor diabetes and kidney disease in real-time.
The study was led by Ali Yetisen, a chemical engineer at the Technical University of Munich, Germany. According to a paper published in the authoritative journal 《Angewandte Chemie》, the ink penetrates the skin in much the same way as general tattoo ink, but the formula is similar. The ingredients are very different.
Researchers say this is a technology that combines tattoo art with biometric colorimetric sensors. A typical tattoo is to inject ink directly into the dermis, allowing the pigment to permanently adhere to the skin. Scientists inject three different colorimetric sensors into the skin. This part of the skin changes color when biological indicators such as pH change.
Each sensor is responsible for monitoring a biological indicator, and the color changes are different due to different recipes.
When the body's pH changes from acidic to alkaline, the tattoo changes from yellow to blue. The sensor that monitors albumin is itself a yellow dye that turns green once it binds to albumin. The blood sugar rises from yellow to dark green.
Why choose these three indicators for monitoring? Researchers say this is because many of the problems in the human body are often fed back through these indicators. Hyperglycemia can lead to diabetes, while decreased albumin levels can mean liver and kidney failure, and high pH can cause acidosis and alkalosis.
In order to make it easier for patients and doctors to understand the meaning of these tattoo color changes, the researchers developed an app. As long as you take a tattoo with your mobile phone, the app can analyze the corresponding health indicators.
At present, researchers have tested "color-changing tattoos" on pigskins, but they have not been tested in humans. The next step for the researchers is to test the effects of living animals to see if they cause some adverse reactions.
The advantage of this technology over existing health monitoring methods is that sensors can be placed directly into specific locations in the body, recording changes in metabolites in real-time, regardless of space and time constraints.
Ali Yetisen believes that this “color-changing tattoo” can permanently monitor patients with simple, low-cost technology. With the development of colorimetric biosensors, the indicators of monitoring can be extended to record electrolytes, pathogen concentrations, or patients in the future. The degree of dehydration, etc.
In fact, two years ago, MIT published a "color-changing tattoo" study, which also used three kinds of nano-scale biosensors instead of tattoo ink to inject into the skin to monitor the PH value, blood glucose, and sodium concentrations. And also has been released with a video of "color-changing tattoos" on the hands, but this is just a concept video.
Although this technology needs more tests to be able to really enter the market, in recent years based on biosensor-based tattoo-type electronic skin, it has made many breakthroughs, and even hope to achieve mass production.
The development of electronic tattoos may be faster than you think.
In addition to "color-changing tattoos", there are more electronic tattoos using skin-like flexible sensors. The appeal of these electronic tattoos is not only continuous monitoring but also don’t need needles for non-invasive monitoring.
A study published by the Tsinghua University team in the journal Science Advances in 2017 showed a new way to monitor non-invasive blood glucose, using a device similar to a tattoo sticker to complete blood glucose monitoring without puncturing fingers.
It uses a counter ion electroosmosis technique to apply a small electric field to the surface of the skin and uses the generated ion current to allow the blood glucose of the subcutaneous tissue fluid to permeate to the surface of the skin. Finally, it is accurately measured by a 3.8 micron thick ultra-thin flexible biosensor.
The breakthrough in this technology is the integration of complex monitoring systems on a skin-like flexible biosensor with a thickness of only 3.8 microns, which involves the intersection of mechanics, materials, chemistry, biochemistry, electronics and many other disciplines.