Ionic liquid regenerated cellulose membrane electroless plated by silver layer for ECG signal monitoring

Abstract

Nowadays, more and more attention has been paid to flexible electrodes, which can be used to make wearable devices so as to monitor health signals, such as those in ECG, EMG and EEG. However, the contact impedance of many membrane electrodes is high due to the bad fit between the sensors and the skin, or the poor sensitivity caused by low conductivity. Therefore, we fabricated a skin-like conductive electrode via electroless silver plating on the surface of regenerated cellulose membrane, which was prepared from the cellulose dissolved in ionic liquid [Bmim]Cl. The as-prepared biocompatible electrodes with low skin-electrode contact impedance can be used as a dry electrode for a long time. Its impedance at 700 Hz is only 8 kΩ/cm2 and the conductivity reaches 252 s/cm. After 5 h of wearing, the electrode-skin contact impedance at 700 Hz is only 10 kΩ/cm2 when 0.20 mol/L AgNO3 is used. In short, the prepared electrode can not only ensure stable and clear ECG signals but also can greatly reduce electrode–skin contact impedance when used for long-term health monitoring.