Flexible non-contact electrodes for minimizing artifacts in electrocardiograms measurement during motion

The Electrocardiogram (ECG) is a critical physiological indicator that contains abundant information about human heart activities. It is a challenge to measure ECG signals, which is susceptible to interference from various types of noise. Generally, the signals are often detected by wet electrodes needing moist conductive gel to reduce the skin-electrode interface impedance, which could cause discomfort of the user and even lead to distortion of the signals due to the drying of conductive gel. In this study, a non-contact electrode that does not need any conductive gel nor ohmic connection with the skin was presented to apply high-quality physiological signals. It was made up of flexible printed circuits materials and the surface signal can be obtained by the principle of capacitive coupling. The results showed that the proposed non-contact electrode could acquire high-quality ECG compared to wet Ag/AgCl electrode. The correlation coefficient of the ECG waveforms was as high as 98.10% in the quiet state and 90.80% in the motion state between standard electrode and our non-contact electrode. The electrode was capable of obtaining good ECG signals even when the subject was walking at a speed up to 6 km/h. This pilot study suggests that the proposed flexible non-contact electrode would be a potential tool for long-term healthcare monitoring for patients and physiological signal measurements for athletes.