Dry electrode made from carbon nanotubes for continuous recording of bio-signals

Health monitoring devices have received attention from individual users and clinicians. For example, the wet-type silver/silver chloride (Ag/AgCl) electrode is used to record bio-signals such as electrocardiogram (ECG) and electromyogram (EMG). However, when used for long durations, an Ag/AgCl electrode with an electrolyte gel causes signal distortion and degradation and can irritate the skin. In this study, we developed a dry-type self-adhesive electrode composed of a mixture of carbon nanotubes and adhesive-polydimethylsiloxane. This electrode can be attached to the skin by creating a vacuum between the epidermal and electrode surfaces, allowing for long-term recording of bio-signals without side effects. We analyzed the electrical and mechanical characteristics and verified the performance of the proposed electrode compared to that of an Ag/AgCl electrode by conducting ECG and EMG measurements. Moreover, the composite electrode was attached to the skin for one week, and no skin irritation, itchiness, or remarkable degradation of the bio-signals such as ECG was observed. This electrode enables long-term health monitoring of patients with chronic conditions. Additionally, this comfortable electrode can be applied to a wearable device, including for bio-signal detection.