Electromyography (EMG) is regularly used to assess muscle activity in patients, but it’s not effective for long term monitoring and high fidelity applications because it relies on gelled electrodes to work. Dry electrodes are not effective enough at creating a consistent electrical connection with the skin, but now researchers at Tel Aviv University in Israel developed new dry electrodes that are able to record high quality EMG while being comfortable for the wearer.
The researchers made a tattoo-like device that is able to continuously perform electromyography on the muscles of the face and hand. The new electrodes consist of a carbon ink screen printed onto a soft, flexible material. Because they have high conductivity while staying adhered to the skin during movement, the conductive gel becomes unnecessary.Besides studying muscle activity, the researchers believe the new electrodes can lead to novel brain-machine interfaces, muscle diagnostics, rehab, and gaming applications.
According to the study Temporary-tattoo for Long-Term High Fidelity Biopotential Recordings from Scientific Reports, “The electrodes were realized using screen-printing of carbon ink on a soft support. The conformity of the electrodes helps establish direct contact with the skin, making the use of a gel superfluous. Plasma polymerized 3,4-ethylenedioxythiophene was used to enhance the impedance of the electrodes. Cyclic voltammetry measurements revealed an increase in electrode capacitance by a factor of up to 100 in wet conditions. Impedance measurements show a reduction factor of 10 in electrode impedance on human skin. The suitability of the electrodes for long-term electromyography recordings from the hand and from the face is demonstrated.”