Liquid graphene sensor could save lives of babies

11 January 2018

A newly developed technology could better track infant health metrics such as pulse and breathing rate, than existing devices which are cumbersome. The new technology uses conducting liquid emulsions, which have been detailed in a paper published yesterday in the Nanoscale journal from the Royal Society of Chemistry. The technology draws inspiration from the Bill and Melinda Gates Foundation's plea for cheap wearable tech that can track the health of babies.

University of Sussex researchers have developed a sensor that could someday keep babies from dying of sudden infant death syndrome (SIDS). The sensor takes the form of a flexible rubber tube filled with a solution of water, oil and particles of graphene.

The one-atom-thick graphene sheet of linked carbon atoms, is highly electrically conductive, which means the solution also conducts electricity, although its conductivity changes when the tube is stretched by even a tiny amount. The change can be detected, which indicates that movement (such as the rising and falling of a breathing person's chest) is occurring.

"What we've done is similar to how you might make a salad dressing; by shaking together water and oil, you make tiny droplets of one liquid floating in the other because the two don't mix," explains lead researcher Dr Matthew Large, reported. "Normally, the droplets would all collect together and the liquids separate over time We've resolved this by putting graphene in. The graphene, which is an atom thick, sits at the surface of the droplets and stops them from coalescing."

"When the graphene particles are assembled around the liquid droplets, electrons can hop from one particle to the next; this is why the whole liquid is conductive," he added. "When we stretch our sensors we squeeze and deform the droplets; this moves the graphene particles further apart and makes it much harder for the electrons to hop across the system."

Sensors can be attached to sleeping babies in the form a fitness tracker-like band or integrated into their clothing which could monitor the infants' heartbeat and respiration, causing an alarm to sound if either stopped.

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