This electronic tattoo can measure your blood pressure better than a smartwatch

Getting a new tattoo isn’t just about looking cool (or making a decision you’ll regret years later)—it can save your life, too. At least that’s the idea behind a new electronic tattoo that can continuously and unobtrusively measure blood pressure.

In an article published in the magazine on Monday nature nanotechnology, A team from the University of Texas at Austin and Texas A&M University has developed a device that attaches to the skin of the wrist and can be worn comfortably for up to 24 hours. It can continuously monitor blood pressure with incredible accuracy, potentially helping diagnose problems as they arise and informing the management of patients with serious heart conditions. Researchers hope it will pave the way for a blood pressure monitor that doesn’t require a cuff like a traditional bracelet.

“Blood pressure is an important reading,” 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 isn’t enough, and cuff-based solutions are cumbersome, uncomfortable, and impractical.

Photo illustration by The Daily Beast / Photos by University of Texas at Austin/Texas A&M University

When it comes to the world of blood pressure monitoring, a cuffless device is indeed the “holy grail,” Jafari said. That’s because cuffed devices are often uncomfortable to wear, and cardiac monitoring products like smartwatches tend to move around the wrist too much 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 placed directly over the arteries in a person’s wrists. Not only is it incredibly durable, but it’s also the thinnest material on earth. This makes it perfect for use in an e-tattoo as the wearer will not even feel it on their skin.

It is also applied just like a temporary tattoo: a piece of paper is placed over the wrist area, which is then dabbed with some water. After a few seconds the paper is removed and voila – you have a slick new cyberpunk tattoo. Unfortunately, it is not quite enough to measure the heart rate.

Photo illustration by The Daily Beast / Photos by University of Texas at Austin/Texas A&M University

“We have these circuits that we have to connect to the skin to get information about 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, there is that reliable and long-lasting bond with the skin.”

The circuits lead to a small electronics box that transmits the information to a computer that uses machine learning to generate the biometric data. The whole system works by sending an electrical current into the skin of your arm, which allows it to detect changes in the volume of the arteries in your arm, ie changes in blood pressure.

“You have blood pumping through the arteries,” Dmitry Kireev, a bioelectronics researcher at UT in Austin and co-author of the study, told The Daily Beast. “This will change the volume of the arteries and that’s what we’re recording.”

Photo illustration by The Daily Beast / Photos by University of Texas at Austin/Texas A&M University

Mind you, this is just a prototype. The team hopes to continue refining the system so it can be adapted to smartwatches for much more accurate blood pressure readings. That would be a massive improvement over current smartwatch tech, which relies on an optical system to detect your heart rate – which is problematic for a number of reasons.

For one, the optical system relies on how light reflects off your skin, “but that light only penetrates so much,” Sel said. Even people with darker skin tones have a notoriously harder time with these systems.

The E-Tattoo could lay the groundwork for a commercial cuffless blood pressure monitor that would allow patients to recognize and send vital biometric data to their doctors without being connected to a cumbersome device. That data can include things like “muscle contractions, hydration, changes in tissue composition, or even respiration,” according to Sel.