By Stephen Beech via SWNS
Homemade “play-putty” can read the body’s vital electric signals.
The innovative material – dubbed “squishy circuits” – is able to monitor brain, heart, muscle and eye activity.
It could open a new field of flexible, cost-effective biometric sensors, say American scientists.
A new study by researchers at the University of Massachusetts Amherst, published in the journal Device, outlines the conductive properties of the material.
Study senior author Dr. Dmitry Kireev said: “Squishy circuits are literally child’s play putty, that is also conductive.”
He explained that the squishy circuits – whether homemade or store-bought – are made from flour, water, salt, cream of tartar and vegetable oil.
Dr. Kireev, Assistant Professor of biomedical engineering, said: “Salt is what makes it conductive.”
He says, as a child’s toy, the modeling clay is a malleable way to add lights to an art project by connecting them to a power source as a way to teach youngsters about circuits.
Now, Dr. Kireev and his team have shown that the material has more potential.
He said: “We used the squishy circuits as an interface to measure electricity or measure bioelectrical potentials from a human body.”
The team found that, compared to commercially available gel electrodes, the squishy circuits effectively captured various electrophysiology measurements: electroencephalogram (EEG) for brain activity, electrocardiogram (ECG) for heart recordings, electrooculogram (EOG) for tracking eye movement and electromyography (EMG) for muscle contraction.
Dr. Kireev said: “What makes one electrode material better than another in terms of the quality of the measurements is impedance,”
He explained that impedance is a measure that describes the quality of conductivity between two materials.
Dr. Kireev said: “The lower the impedance between the electrode and the tissue, the better the conductivity in between and the better your ability to measure those bioelectrical potentials.”
The study found that the impedance for the squishy circuit electrode was on a par with one of the commercially available gel electrodes and twice as good as a second comparison electrode.
Dr. Kireev says the new material is cheap as, even using pre-made putty, the cost per electrode was about one cent. Typical electrodes cost on average between $0.25 and $1.
He says the material is also resilient as it can be formed and reformed, molded to the contours of the skin, combined with more putty to make it bigger, reused and easily reconnected if it comes apart.
Dr. Kireev says other comparable state-of-the-art wearable bioelectronics have been made of carbon nanotubes, graphene, silver nanowires and organic polymers.
But, while highly conductive, those materials can be expensive, difficult to handle or make, and are single-use or fragile.
Dr. Kireev added: “It’s something you can do at home or in high school laboratories, for example, if needed.
“You can democratize these applications so it’s more widespread.”
