Graphene device monitors blood pressure continuously

A new blood pressure monitoring device made from graphene could help people keep better track of their cardiovascular health. The array of stick-on graphene sensors, dubbed graphene electronic tattoos, can measure blood pressure continuously over the course of hours. Data from this device would give doctors a better overall picture of blood pressure than using measurements from a blood pressure cuff taken a few times a day.

“Blood pressure provides a holistic view of our cardiovascular system,” says Roozbeh Jafari, a biomedical engineer at Texas A&M University who led the development of the new device along with Deji Akinwande of the University of Texas at Austin. By monitoring blood pressure over the course of hours, rather than in once- or twice-daily measurements, healthcare professionals can eliminate noise in their data—like blood pressure spikes caused by the stress of a doctor’s visit. Also, Jafari says, the graphene device is thin and weightless. It doesn’t squeeze like a traditional blood pressure cuff; it’s simply worn on the forearm (Nat. Nanotechnol. 2022, DOI: 10.1038/s41565-022-01145-w).

The first sphygmomanometer—the device that is the basis for modern blood pressure cuffs—was invented in 1881. While there have been improvements to the device, the technology is essentially the same, Jafari says. The new graphene-based device uses an entirely different process for monitoring blood flow.

Graphene—a material that consists of one or a few sheets of carbon atoms strung together like chicken wire—has the perfect properties for a blood pressure monitor, Jafari says. It can make close contact with skin and has ideal electronic properties. The graphene sensors used in the device were first reported in 2017 (ACS Nano, DOI: 10.1021/acsnano.7b02182). In the new blood pressure monitor, the carbon tattoos inject small electrical currents into the arm and then measure voltage, which correlates with changes in blood volume. The team developed a computer algorithm that translates those changes in blood volume to the traditional systolic and diastolic blood pressure measurements.

The search for a cuffless way to monitor blood-pressure has been a hot topic in recent years, says Tian-Ling Ren, who studies microelectronics at Tsinghua University. He calls the graphene-based device a step forward in this area. “This work will have a significant impact in the field of wearable health monitoring,” he says in an email.

Sheng Xu, who studies wearable electronics at the University of California San Diego, calls the work impressive. He adds that integrating some of the electronics that process the voltage signals into the graphene sensors would be valuable because it would reduce the number of wired connections to the device.

Jafari says the researchers are working on improving their prototype. They’ve filed a patent on the technology, which has been licensed to SpectroBeat.