Researchers from the University of Texas at Austin have successfully demoed graphene tatoos capable of monitoring blood pressure from the wrist continously.
We are still waiting for blood pressure functionality to become a standard stable of fitness trackers and smartwatches. There are a number of technologies in development. However, we are not really expecting them to hit the mainstream at least for another year or two.
The future of blood pressure monitoring clearly lies with the wrist. But it may not need to be built into a wearable. Scientists have demonstrated that tatoos made with graphene can do this job continuously for days at a time.
“The graphene tattoo is weightless, it is invisible. You put it on and you forget about it,” says Deji Akinwande at the University of Texas at Austin.
The tech is quite different from the traditional thing which works by way of inflating cuffs. This captures readings by increasing pressure until no blood flow occurs through the artery. As the cuff deflates, this creates a detectable vibration in the arterial wall which can be used to calculate systolic and diastolic blood pressure.
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But these are one-time measurements so are not continuous. The other negative is that accuracy can suffer as it depends on the positioning of a person’s arm, or due to factors such as current level of stress or dehydration. Not to mention something called White Coat Hypertension. Or in English – some people experience hightened blood pressure whenever they take a reading in the doctor’s office.
The tattoo works around the clock
The tattoo, on the other hand, is much more convenient as it captures readings without you having to do a thing. Researchers say it has the ability to continously capture readings with “Grade A” accuracy as set by international standards.
As shown in the picture above, the tech consists of 12 tiny graphene strips which are printed in two rows along the two main forearm arteries. The outermost strips in each row ping electrical signals into the arm. The inner strips are where alterations in blood flow are detected as voltage changes.
University of Texas researchers have tested the tattoos on six people as they went about their day. The tech worked even when they were doing push-ups or plunged their arms into ice-cold water for a minute. Readings were also captured overnight without disturbing the volunteers’ sleep.
“We want to move towards measuring the blood pressure continuously and what I call passively, meaning that you don’t even know when your blood pressure is being measured,” said team member Roozbeh Jafari.
Granted, the participants were all healthy individuals with no blood pressure abnormalities. In the future, scientists want to use the tech to see if it works to the same degree of accuracy for people with elevated blood pressure.
The blood pressure tattoo is very much a demonstration of what can potentially be done. It is nowhere close to ending up in a product that can be used by hospitals or individuals. That’s because most of the hardware necessary to record and analyse the data needs to sit nearby and is connected by a wire. But once a wireless tech is integrated one could imagine this sort of technique being used in conjunction with a smartwatch which could act as the analysis hub.
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