Researchers have developed an electronic tattoo that delivers continuous blood pressure monitoring at high accuracy.

Blood pressure is the most vital indicator of heart health, and although there is a range of monitoring devices, it remains difficult to reliably measure outside of a clinical setting. Researchers at The University of Texas at Austin and Texas A&M University have developed an electronic tattoo that could change the face of blood pressure monitoring forever.

“Blood pressure is the most important vital sign you can measure, but the methods to do it outside of the clinic passively, 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.

The findings are published in Nature Nanotechnology.

Designing the electronic tattoo

The electronic tattoo continuously monitors blood pressure, meaning that measurements can be taken at all points of time: in stressful situations, during sleep, and throughout exercise, for example. The electronic tattoo delivers more measurements than any other available device.

Electronic tattoos are the ideal candidate for blood pressure monitoring outside a clinical setting due to their material make-up. Graphene is the key ingredient as one of the strongest and thinnest materials in existence; it perfectly shapes around the wrist. The device encases sensors that can be comfortably worn for long periods and stick perfectly to the skin.

“The sensor for the tattoo is weightless and unobtrusive. You place 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 around, the measurements are going to be different.”

How does the device take measurements?

The electronic tattoo takes measurements by shooting an electrical current into the skin and then analyses the body’s response, known as bioimpedance. This is monitored due to the strong correlation between bioimpedance and changes in blood pressure. Despite this, the correlation is not apparent, leading the researchers to create a machine learning model that analyses the relationship to get accurate blood pressure readings.

In medicine, cuff-less blood pressure monitoring is the “holy grail,” Jafari said, but there is not a viable solution on the market yet. The electronic tattoo development is part of a larger push in medicine to use technology to release patients from machines with equipment that continues to collect accurate data in all settings.

“All this data can help create a digital twin to model the human body, to predict and show how it might react and respond to treatments over time,” Akinwande said.