Soft Gel-free ECG electrodes based on Biocompatible Coconut-Oil and Carbon Black

Recent developments in telemedicine have caused significant interest in the prolonged monitoring of bioelectric signals. This drives the search for easy-to-use, biocompatible, and environmentally friendly alternatives to conventional resistive wet electrodes. Here we demonstrate the use of Coconut-Oil and Carbon Black based stretchable dry electrodes to monitor electrophysiological signals without the need for conductive gels. The developed material is embedded into an elastomer matrix, exhibits a specific resistance rho of 33.2 +/- 12.3 Omega m, high conformability, and a stretchability up to 1500%. The realised epidermal electrodes were used to record Electrocardiographic (ECG) signals in a 3-lead configuration and compared to commercial wet electrodes. Even after being elongated by 100% for 100 stretch/release cycles, a reliable recording of the QRS-complex is demonstrated without the need for any contact enhancing or skin irritating substances, proving its potential use in long term ECG monitoring applications.