Continuously monitoring the biopotential signals such as the electrocardiogram (ECG) of a person can provide vital information for diagnosis and treatment. Electrodes are usually mounted onto the skin to detect the biopotential signals, and the popular electrodes are made of Ag/AgCl gel electrolyte today. Although the Ag/AgCl gel electrodes can give rise to high-quality signal on patients at rest in the clinic setting, they are not suitable for continuous healthcare monitoring for the long term. High motion artifacts can be observed during body movement that affects the contact between the Ag/AgCl gel electrodes and skin. The liquid's vaporization in the Ag/AgCl gel electrodes can increase noise or even generate fault signals.
Dry electrodes can overcome the problems related to the Ag/AgCl gel electrodes for healthcare monitoring. Though various dry electrodes were reported in the literature, their performance is not good enough for long term healthcare monitoring. The problems include motion artifacts during body movement, skin irritation, and toxicity of the materials.
Recently a team at the National University of Singapore (NUS) developed high-performance dry electrodes for biopotential monitoring. The dry electrodes are made of bio-compatible intrinsically conducting polymers with additives. Because they can have high conductivity, high mechanical stretchability, and self adhesiveness to the skin, they can always give rise to high-quality biopotential signals. For more information, please refer to their recent publication at Nature Communications.
The ECG's noise on a volunteer at rest is even lower than the standard Ag/AgCl gel electrodes. In addition, the ECG signals are hardly affected by body movements. They demonstrated the application of their dry electrodes for long-term healthcare monitoring. They also demonstrated the dry electrode's application for electromyogram (EMG) and electroencephalogram (EEG). The dry electrodes were tested on patients in the clinic as well.
The paper can be found and downloaded at https://rdcu.be/b7kK0.