Medical research: Measuring blood pressure with an electronic tattoo

An electronic tattoo made of graphene is said to help measure blood pressure. A team from Texas has tested the scientific method.

A research team from the Universities of Texas at Austin and Texas A&M has developed an electronic tattoo that can provide continuous blood pressure measurements. Its accuracy is said to surpass options available on the market.

In addition, the tattoo is said to fit comfortably on the wrist. And here's where it quickly becomes apparent: this is not a tattoo you'd get from a tattoo artist. "The sensor for the tattoo is weightless and unobtrusive. You place it there. You don't even see it," Roozbeh Jafari describes him. He is a professor of biomedical engineering, computer science and electrical engineering at Texas A&M and co-leader of the project.

A strange electronic tattoo

An e-tattoo is well suited for mobile blood pressure monitoring, according to the University of Texas site. It's in a sticky, stretchy material that encases the sensors. And it's said to be comfortable to wear over a long period of time.

The e-tattoo is made of a material called graphene, which is similar to the graphite found in our pencils. However, its atoms are precisely arranged in thin layers, making graphene one of the strongest and thinnest materials.

Unlike smartwatches, which can also be used to measure blood pressure, the electronic tattoos do not slip. The research team's criticism: smartwatches may be far from the arteries, making accurate readings difficult. Those with a larger wrist or darker skin color also could get faulty and faltering data from the light-based measurement, they said.

"Blood pressure is the most important vital sign you can measure, but the methods to measure it outside the clinic passively without a cuff, are very limited," explains Deji Akinwande. He is the project's co-leader and a professor in the Department of Electrical and Computer Engineering at UT Austin.

Here's how blood pressure measurement works with an electronic tattoo

The e-tattoo measurement is done by shooting an electric current into the skin. After the small jolt of electricity, the body's response is analyzed using bioimpedance measurement. In this process, the body composition of a person is analyzed by recording individual values such as water, body cell mass and fat.

As soon as the blood volume changes, the blood pressure also changes. There is a weak correlation between blood pressure changes and bioimpedance, which the research team first had to study by using artificial intelligence. They then succeeded in obtaining blood pressure values that are even more accurate than almost all measurement options available on the market today.

The research results were published in the journal Nature Nanotechnology on June 20, 2022, under the title Continuous cuffless monitoring of arterial blood pressure via graphene bioimpedance tattoos.

This method can provide blood pressure data in almost all circumstances, whether during stressful times, exercise, or sleep. However, the study involved only seven subjects who wore the electronic tattoo for more than 300 minutes - not exactly representative. Whether the technology will be suitable for mass use remains to be seen.