Fabrication of [email protected] Nanocomposite-Based Gel-Free Electrode to Acquire ECG Signal

Electrocardiogram (ECG) signals are widely used to interpret the heart’s electrical activity and are conventionally measured using gel-based ECG electrodes. In this study, Iron (II, III) oxide (FeO.Fe2O3) or (Fe3O4)–graphene nanoplatelets (GNP), designated as FG, was prepared in different compositions (1.5:1.5, 2:1, 3:0 wt/wt) and incorporated into polyvinylidene fluoride (PVDF) polymer via a solution mixing approach to develop PVDF@Fe3O4-GNP (PVDF@FG) polymer nanocomposites. These PVDF@FG suspensions were then cast onto bare Ag/AgCl electrodes to fabricate gel-free ECG electrodes. The nanocomposites (NC) and ECG electrodes were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy analysis, and impedance measurement techniques. The as-prepared gel-free electrodes were integrated with an Arduino microcontroller to acquire the ECG signals. Among the compositions tested, the PVDF@FG NC electrode with a 1.5:1.5 Fe3O4–GNP ratio exhibited superior conductivity and sensitivity, demonstrating a nominal signal-to-noise ratio. The ECG spectra revealed the enhanced R peak and increased R-R peak separation compared to bare Ag/AgCl electrodes, indicating improved signal acquisition with reduced noise. These findings suggest that the proposed gel-free ECG sensor is a promising alternative to conventional gel-based ECG electrodes, offering enhanced signal acquisition performance and reliability.