A conductive-modified sponge-based PVA physiological saline hydrogel semi-dry electrode for high-quality noninvasive electrophysiological signal recording

With the growing demand for noninvasive monitoring of electrophysiological signals for healthcare and medical diagnostics, the development of flexible and sensitive biosensors has become increasingly important. This work reports a polyurethane/nickel sponge with a PVA/PEDOT:PSS electrode (PuNiPPE) for noninvasive electrophysiological signal recording. The PuNiPPE is constructed on a polyurethane sponge substrate that undergoes surface conductive modification through chemical nickel plating and is filled with a PVA physiological hydrogel incorporating PEDOT:PSS. This design endows PuNiPPE with exceptional flexibility, allowing it to closely adhere to the skin and achieve high-quality signal acquisition. The electrode demonstrates high electrical conductivity and a sustained release mechanism of physiological saline, resulting in low impedance (2829.3 Ω at 1000 Hz) and enhanced electrical stability. In practical applications, PuNiPPE outperforms commercial electrodes in signal-to-noise ratio (SNR), with 23 dB compared to 17 dB, suggesting that PuNiPPE could be a promising solution for improving the efficiency and reliability of wearable biosensors in electrophysiological monitoring.