IEEE Spectrum is reporting that researchers, Deji Akinwande and Nanshu Lu at the University of Texas at Austin, have developed a bio-integrated health sensor that can be applied to the skin like a temporary “tattoo” to take measurements of vitals signs. Utilizing graphene, the tattoo has a significantly smaller form factor than conventional sensor equipment. It is graphene’s unique characteristics that lends the material to the flexible electronic tattoo. Its one atom thick structure allows it to be flexible enough to move with the skin while its mechanical resilience allows it to withstand damage from the stretching and compression the tattoo would undergo. Plus, being conductive makes it a perfect material for a minimalist and non-invasive vitals monitoring system.
The researchers start by depositing an atom thick layer of graphene onto a sheet of copper. In the next step, the graphene is coated with a stretchy base layer polymer and the copper is etched off. Once the copper is removed, the graphene sheet is placed on a temporary dissolvable tattoo paper for future application to the skin. The graphene is then carved into electrodes and the spiral connections that bridge the gap between each graphene island. The shape and flexibility of the graphene tattoo allow it to conform to the tiny ridges and valleys that cover our skin to make a more intimate contact with the surface and the sensor. This complete contact between the sensor and skin essentially removes the need for adhesives.
The sensor is applied by placing the temporary tattoo paper carrying the graphene onto the skin and adding water. The sensor is held in place by electrostatic forces strong enough to adhere the one atom thick circuitry. The lack of adhesive, combined with the intimate connection of the 0.3 nm thick circuitry, allow the device to take high quality measurements.
These graphene tattoos can measure electrical signals from the heart, muscles, and brain as well as measure skin temperature and hydration levels. The researchers tested the device by taking various measurements including EKG, EEG, EMG, skin temperature, and hydration. The quality of data collected by the “temporary” electronic tattoo was comparable to larger conventional devices.
The future looks bright for these two scientist and their temporary graphene tattoo. The uses for this type of bio-integrated technology are limitless, creating the potential to make less obstructive and more portable health and vital measuring devices.
Via: IEEE Spectrum…