This Low-Cost, Graphene Device Could Help Monitor a Baby’s Health

Physicists have developed a graphene-based liquid that can sense tiny changes in breathing and heart rate


This graphene-filled tube is sensitive to the slightest movements.
(University of Sussex)

By

Emily Matchar

smithsonian.com

When sick babies are in the hospital, they lay amidst an often-overwhelming nest of wires—monitors to measure breathing, heart rate, blood oxygen, temperature and more. Feeding, dressing or even picking up a baby wearing these devices can be tricky. But researchers at the University of Sussex in the UK could potentially provide a wire-free solution, either via a tiny Fitbit-like bracelet or with tubes sewn into a baby’s clothing.

The team of physicists has developed a liquid made from an emulsion of graphene, water and oil. Graphene is a nanomaterial made from carbon atoms. It’s become the darling of materials scientists in recent years because of its strength, flexibility, electrical conductivity and—importantly—its affordability. The team put the graphene emulsion inside a tiny tube. When the tube was stretched ever so slightly, the conductivity of the emulsion changed. The prototype device is so sensitive it can detect subtle bodily movements, like breathing and pulse rates.

The researchers suspect the tiny graphene-filled tube could be a cheap, unobtrusive monitor for sick babies and for adults with breathing problems, such as sleep apnea. It could also be sold as a baby product to parents worried about SIDS (Sudden Infant Death Syndrome), potentially in the form of a wearable suit to monitor a baby’s vital signs. Beyond these applications, it’s quite possible it could also be used to create a more advanced generation of wearables for both amateur and professional athletes. 

Alan Dalton, the project’s lead researcher, says the development of this technology started off as a curiosity. «If you think about mixing oil and water (i.e. vinegar) when making a salad dressing, the two liquids will always separate over time. It’s quite well known that adding soap-like molecules or certain fine powders to oil and water can stop them from separating,» he says. «What we wanted to know was whether graphene could achieve the same effect. Not only did we discover that this does indeed work, but we also observed that the liquid structures we were able to make were electrically conducting.»

The research was described in a paper published last month in the journal Nanoscale.


A micrograph of the graphene, water and oil emulsion developed by the University of Sussex team.

(University of Sussex)

“What’s quite exciting about this new type of conductive liquid is how sensitive it is to being stretched,» said physicist Matthew Large, the first author on the paper, in a university press release. »The sensitivity of this new kind of strain sensor is actually much higher than a lot of existing technologies, and it is the most sensitive liquid-based device ever reported, by quite a significant margin.»

The team created the graphene-filled tube after hearing a call from the Bill and Melinda Gates Foundation for scientists to create affordable wearable technologies to monitor babies in low-resource environments. A monitor based on the team’s technology would require no expensive materials or special knowledge and could easily be shipped to remote locations. The researchers are currently working with a commercial partner to develop products for market in the next several years. 

“This research describes a novel way of measuring ‘strain’ or movement,” says David King, a pediatrician and lecturer in pediatrics at the University of Sheffield in the UK. “They have extrapolated their findings to suggest this may be useful to measure vital signs either directly or remotely in a more sensitive way.”

It’s difficult to know how this will work, though, since no devices have been manufactured yet, King says. And he strongly cautions against the idea that this device—or any device—could be used to prevent SIDS.

“The premise that measuring vital signs [will] reduce the incidence of SIDS is unsupported by current evidence,” he says.

Interestingly, Dalton sees this technology as having applications beyond health. 

«The ability to measure very small stretches or vibrations could be incredibly useful,» he says. «Think about detecting shifts in the structure of tall buildings or bridges; or being able to deploy vast numbers of sensors looking for the vibrations associated with geological events.»

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