Chitosan and Alginate Based Conductive Gels for Electroencephalography: Comparative In Vitro Characterization of Fifteen Formulations

Abstract

Electroencephalography (EEG) relies on conductive gels for effective electrode–skin contact, but conventional gels dehydrate, leave residue, and are not biodegradable. This study developed marine-derived gels from chitosan, sodium alginate, and chitosan–alginate hybrids, with selected formulations reinforced with montmorillonite. Of 35 formulations, 15 homogeneous gels were characterized for physicochemical and electrical properties. Gel-only impedance decreased from 85–230 kΩ at ~20 Hz to 21–80 kΩ at 1 kHz, with phase angles shifting toward increasingly resistive behavior. ALG-6*, a montmorillonite-containing alginate gel, combined the highest viscosity, lowest contact angle, and favorable interfacial impedance, and was provisionally prioritized pending biocompatibility and EEG signal-quality testing.