Researchers in Ireland have developed a form of Silly Putty that, when applied to a person, can measure physiologic signs like respiratory rate and even the pulse waveform of an artery.
Health wearables can measure many different physiologic signs. Devices like the Apple Watch and Fitbit can measure your heart rate and movement. With AliveCor’s Kardia Band, the Apple Watch can capture single-lead EGGs. Many of these same sensors are being built into apparel like shoes and shirts as well.
A group of researchers in Ireland have now used a form of Silly Putty, something many of us remember from our childhood, to create a promising new sensor that could change how we think of health wearables. Describing it as Silly Putty is a bit of a stretch – they call it viscoelastic graphene-polymer nanocomposites in the Science paper describing the innovation. For the not material science scientists out there, the translation is that they added graphene to the type of material that makes up Silly Putty. Doing that created a material that can conduct electricity and, more importantly, the way it conducts electricity is exceptionally sensitive to pressure changes.
In their manuscript, they describe applying a small amount of this material over the carotid artery and show a pulse waveform they generated, complete with a dicrotic notch. They also show an example of the material being used to measure respiratory rate, with a tracing similar to what many of us see in the hospital from impedance-based respiratory sensors. These are just exploratory examples but demonstrate the potential of the substance to measure any physiologic sign associated with movement or a pressure change.
Many of the devices we’ve seen to date use miniaturize existing technology, like photoplethysmography or triaxial accelerometers, and build it into devices like smartphones or smartwatches. However, advances in material science and other fields could open entirely new ways to measure the physiologic signs we care about or perhaps discover even discover new ones.