Ionic Passivation and Oxidation Dynamics for Enhanced Viability of Copper-Based On-Skin Bioelectrodes in Biological Environments

Abstract

The integration of bioelectronic devices with the skin is a promising strategy for personalized healthcare monitoring and diagnostics. On-skin bioelectrodes hold great potential for the real-time tracking of physiological parameters. However, per-sistent challenges of stability and reliability have instigated exploration beyond conventional noble metals. This study focuses on the ionic passivation and oxidation dynamics of copper-based on-skin thin-film bioelectrodes. Through parylene chemical vapor deposition, we harness a controlled thin film of parylene insulation to counter the intrinsic susceptibility of copper to oxidation in the ionic environment. The results represent the relationship among the parylene insulation thickness, copper oxidation, and electrode impedance over temporal intervals. Comparative analyses indicate that the short-term stability of the copper electrode is comparable to that of the gold electrode. Therefore, we propose a cost-effective strategy for fabricating copper-based on-skin bioelectrodes by introducing enhanced ionic stability within a discernible operational timeframe. This study enriches our understanding of on-skin bioelectronics and affordable material choices for practical use in wearable healthcare devices. © 2023, Korean Sensors Society. All rights reserved.