Dry Composite Electrodes with Carbon Nanotubes Additive for Biopotentials Measurements: ECG use case

Dominik Grochala1, Marcin Kajor2, Paweł Smoleń3, Piotr Augustyniak4, Krystian Gruszka5
1Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering, AGH University of Science and Technology, 2AGH, 3Smart Nanotechnologies S.A., 4AGH Univ. of Science and Technology, 5Department of Cardiology, Interventional Electrocardiology and Arterial Hypertension, Jagiellonian University Medical College


Abstract

Long term monitoring of patients health condition is a useful diagnostic method however it still remains challenging to apply. Prolonged electrocardiographic monitoring and early diagnosis of arrhythmias enables the introduction of appropriate treatment prolonging life expectancy . For example in patients with cryptogenic stroke correlation between the duration of ECG monitoring and paroxysmal atrial fibrillation is observed which allows treatment introduction to prevent ischemic stroke. On the other hand the market demand is focused on wearable solutions which do not require to stick electrodes to skin . This approach helps to avoid side effects such as skin irritation and increases patient's comfort in daily recordings. In this research we developed samples of material and evaluated them for suitability in electrophysiological measurements. Favorable conductive properties were achieved by polymer composite containing multi-walled carbon nanotubes and Ag nanoparticles. In addition, considering the prolonged measurement, we carried out microbiological tests according to ISO 22196 to analyze the antimicrobial properties of prepared samples. Combination of thermally-cured silicone resin and carbon nanotubes as a conductive nanoadditive allowed to obtain better mechanical properties than standard wet Ag/AgCl electrodes. ECG signals were recorded in limb leads configuration using M-TRACE Electrocardiograph device. As a reference standard metal electrodes were used. The examination was conducted in two variants: with and without conductive gel. The signals were then compared and approved by a professional physician as fully diagnostable. Comparing to reference electrodes, without gel higher amplitude (by 27%) and higher baseline noise (by 60%) with gel, sequentially 23% and 55% were observed in our studies. Influence of these factors needs further research with various skin types and weeklong records. The results showed that designed material features antimicrobial properties(against S. aureus, E. coli) and the tested electrodes can fully perform their diagnostic function although their properties may require minor tuning.