Getting a new tattoo isn’t only about looking cool (or making a decision you’ll regret years later)—it could also save your life. At least, that’s the idea behind a new electronic tattoo that can continuously and unobtrusively measure your blood pressure.
In a paper published Monday in the journal Nature Nanotechnology, a team from the University of Texas at Austin and Texas A&M University developed a device that can attach to the skin of the wrist and be worn comfortably for up to 24 hours. It can continuously monitor blood pressure with incredible accuracy, potentially helping diagnosis arising and inform the treatment of patients with serious heart conditions. Researchers hope that it will pave the way for a blood pressure monitor that doesn’t require a cuff device like a traditional armband.
“Blood pressure is an important metric,” Roozbeh Jafari, a professor of biomedical engineering at Texas A&M and co-author of the study, told The Daily Beast. “It gives us a holistic view of the entire cardiovascular system. But if you want to measure it, just one or a few measurements a day is not enough, and cuff-based solutions are inconvenient, uncomfortable, and impractical.
In fact, when it comes to the world of blood pressure monitoring, having a cuffless device is the “holy grail,” Jafari said. That’s because cuffed devices are often uncomfortable to wear, and heart monitoring products like smartwatches also tend to move around the wrist too much to be able to provide accurate data.
That’s why the Texas team turned to graphene—a material similar to graphite pencils—to create a tattoo that can be applied directly over a person’s arteries in their wrists. Not only is it incredibly durable, but it’s also the thinnest material in the world. This makes it perfect to be used in an e-tattoo as it allows the wearer to not even feel it on their skin.
It’s also applied exactly like a temporary tattoo: A piece of paper is placed over the spot on your wrist, which is then dabbed with a small amount of water. After a few seconds, the paper is removed, and voila—you have a slick new cyberpunk tattoo. Unfortunately, though, it’s not quite enough to measure your heart rate yet.
“We have these circuits that we need to connect to the skin to get the information about the blood pressure,” Kaan Sel, an electrical and computer engineering researcher at Texas A&M and co-author of the study, told The Daily Beast. “The tattoo is the interface. Once the tattoos are transferred, it gives that reliable and long-term connection with the skin.”
The circuits lead to a small box of electronics that transmits the information to a computer, which uses machine learning to produce the biometric data. The whole system works by sending an electrical current into the skin of your arm that allows it to detect changes in the volume of the arteries in your arm, ie, changes in blood pressure.
“You have blood that pumps through the arteries,” Dmitry Kireev, a bioelectronics researcher at UT at Austin and co-author of the study, told The Daily Beast. “This will change the volume of the arteries and this is what we pick up.”
Mind you, that’s just a prototype. The team hopes to further refine the system so it can be adapted to smartwatches, to allow for much more accurate blood pressure readings. That would represent a massive improvement over current smartwatch tech that relies on an optical system to detect your heart rate—which is problematic for a number of reasons.
For one, the optical system is based on the light reflection off your skin “but that light only penetrates so much,” Sel said. Those with darker skin tones also have a notoriously more difficult time with those systems.
The e-tattoo could lay the groundwork for a commercial cuff-less blood pressure monitor that’ll allow the patients to be able to detect and send vital biometric data to their doctors without having to be tethered to a cumbersome machine. This data can include things like “muscle contractions, hydration, tissue composition changes, or even breathing,” according to Sel.