Blood pressure is one of the most important indicators of heart health, but it is difficult to measure frequently and reliably outside of a clinical setting. For decades, cuff-based devices that constrict around the arm to provide a reading have been the gold standard. But now, researchers from the University of Texas at Austin and Texas A&M University have developed an electronic tattoo that can be worn comfortably on the wrist for hours and provides continuous blood pressure readings with an accuracy that surpasses nearly any options available on the market today.
“Blood pressure is the most important vital sign you can measure, but the methods of doing it passively outside the clinic, without a cuff, are very limited,” said Deji Akinwande, a professor in the Department of Electrical and Computer Engineering at UT. Austin and one of the co-leaders of the project, which is documented in a new article published today in Nature Nanotechnology†
High blood pressure can lead to serious heart disease if left untreated. It can be difficult to capture with a traditional blood pressure monitor because it measures just a moment in time, a single data point.
“Taking irregular blood pressure readings has many limitations and does not provide insight into exactly how our bodies function,” said Roozbeh Jafari, professor of biomedical engineering, informatics and electrical engineering at Texas A&M and the other co-leader of the project.
The continuous monitoring of the e-tattoo allows blood pressure measurements in all kinds of situations: in times of high stress, while sleeping, exercising, etc. It can provide thousands of measurements more than any device to date.
Mobile health monitoring has made great strides in recent years, thanks mainly to technology such as smartwatches. These devices use metal sensors that get readings from LED light sources shining through the skin.
However, leading smartwatches are not yet ready for blood pressure measurement. That’s because the watches slip around the wrist and can be far from arteries, making it difficult to provide accurate readings. And the light-based readings may falter in dark-skinned people and/or larger wrists.
Graphene is one of the strongest and thinnest materials available, and it is a key ingredient in the e-tattoo. It is similar to graphite found in pencils, but the atoms are arranged precisely in thin layers.
E-tattoos make sense as a mobile blood pressure measurement vehicle because they are housed in a sticky, stretchy material that encases the sensors and is comfortable to wear for long periods of time and does not shift.
“The sensor for the tattoo is weightless and unobtrusive. You put it there, you don’t even see it and it doesn’t move,” Jafari said. “You need the sensor to stay in the same place because if you happen to move it, the readings will be different.”
The device measures its readings by shooting an electrical current into the skin and then analyzing the body’s response, known as bioimpedance. There is a relationship between bioimpedance and changes in blood pressure related to changes in blood volume. However, the correlation is not particularly clear, so the team had to machine learning model to analyze the connection to get accurate blood pressure readings.
In medicine, cuffless blood pressure monitoring is the “holy grail,” Jafari said, but there is no viable solution on the market yet. It’s part of a bigger push in medicine to use technology to detach patients from machines while collecting more data wherever they are so they can move from room to room, clinic to clinic and still receive personalized care .
“All of this data could help create a digital twin to human bodyto predict and show how it might respond and respond to treatments over time,” Akinwande said.
Roozbeh Jafari, Cuffless Continuous Monitoring of Arterial Blood Pressure via Graphene Bioimpedance Tattoos, Nature Nanotechnology (2022). DOI: 10.1038/s41565-022-01145-w† www.nature.com/articles/s41565/022-01145-w
University of Texas at Austin
Quote: Blood pressure e-tattoo promises continuous, mobile monitoring (2022, June 20) retrieved June 20, 2022 from https://phys.org/news/2022-06-blood-pressure-e-tattoo-mobile.html
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