Controlling blood pressure is very important, especially for people with cardiovascular diseases and those who are a bit older. However, the devices that do that – known as sphygmomanometers – are often bulky, require inflatable cuffs, and cannot produce continuous results. Research might have found an alternative, and it is truly cutting edge.
As reported in Nature Nanotechnology, a team from Texas has devised an electronic tattoo (e-tattoo) made by sticking graphene to the skin. Graphene is an electrical conductor and can be used to transmit a small, safe electrical current that measures the body's bioimpedance, a measurement related to blood pressure.
"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, said in a statement.
"The sensor for the tattoo is weightless and unobtrusive. You place it there. You don't even see it, and it doesn't move," said Roozbeh Jafari, a professor of biomedical engineering, computer science, and electrical engineering at Texas A&M and the other co-leader of the project. "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."
Measuring bioimpedance is an intriguing approach, but doesn’t translate easily to arterial blood pressure. The team had to train a machine-learning algorithm to work out the precise connection and deliver readings with low uncertainty.
The monitoring device was placed above the sticky e-tattoo and could collect data for over five hours, 10 times longer than in previous studies. Being untethered means that blood pressure can be tracked in a variety of scenarios without causing any trouble, like when a person is sleeping or exercising.
"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.
The tech is still not ready, but it is a real and exciting possibility. Graphene is a material made of a layer of carbon a single atom thick. Its incredible properties have been lauded for years, but many promising technologies based on it are still in development, with challenges on how to make them work in the real world.