Graphene “Tattoos” May Be the Future of Blood Pressure Monitoring

A new electronic “tattoo” may be the future of blood pressure monitoring. Researchers have developed a graphene-based e-tattoo that measures blood pressure continuously and has several advantages over the traditional blood pressure cuff, also known as a sphygmomanometer. 

Researchers at Texas A&M University and the University of Texas at Austin developed the new device and published their findings in Nature Nanotechnology. In the experiment, researchers attached an array of stick-on graphene sensors to the forearms of participants. Graphene is a single layer of carbon atoms arranged like chicken wire and has high electricity conducting properties, according to Roozbeh Jafari, a biomedical engineer at Texas A&M who led the development of the new device.

The graphene sticker device uses a method called bioimpedance, which is the response of a living organism to an externally applied electric current. Bioimpedance has an indirect correlation with blood pressure that the new models can calculate, and the researchers developed a computer algorithm that translates those changes to traditional systolic and diastolic blood pressure measurements.

For 300 minutes - a period tenfold longer than any reported in previous studies using e-tattoos - the devices were able to accurately measure the arterial blood pressure of participants. The devices recorded participants’ blood pressure continuously and non-invasively, with an accuracy of 0.2 ± 4.5 mm Hg for diastolic pressures and 0.2 ± 5.8 mm Hg for systolic pressures, a performance equivalent to Grade A classification.

Previously, similar e-tattoo devices have been used to measure the vital signs and muscle responses of people with degenerative diseases. Based on those successes, researchers wanted to use the device to measure blood pressure, given its potential advantages. 

Sphygmomanometers are large and bulky, and when they squeeze a patient’s arm to measure blood pressure, they can cause discomfort. They also are not always accurate, as they give only a tiny snapshot into a person’s cardiovascular situation. A single instance of measuring blood pressure may not be representative of someone’s overall cardiac health, especially because patients’ blood pressure may be affected by their current mood or by the stress of being in a doctor’s office.

Some technology companies, such as those that manufacture smartwatches and fitness trackers, have also tried to use electronic signals to measure blood pressure and heart rate, and although they are non-invasive, they are not always accurate. The devices can move around on a person’s wrist and do not always have software sophisticated enough to give accurate reports of blood pressure or heart rate over an extended period of time.

The lightweight and non-invasive e-tattoo provides a longer view of blood pressure. It also allows patients to perform their everyday activities, giving physicians a more accurate picture of how a patient’s heart reacts to real-life stressors.

“Continuous monitoring of arterial blood pressure (BP) in non-clinical (ambulatory) settings is essential for understanding numerous health conditions, including cardiovascular diseases. Besides their importance in medical diagnosis, ambulatory BP monitoring platforms can advance disease correlation with individual behaviour, daily habits and lifestyle, potentially enabling analysis of root causes, prognosis and disease prevention,” the authors stated.

The researchers have already filed a patent on the technology, which has been licensed to SpectroBeat. They hope to continue honing the device so patients can wear it for longer periods of time, which would give physicians insight into how blood pressure changes during eating, sleeping and exercising. This long-term data would also enable physicians to determine what is and isn't working, particularly for patients with chronic diseases.