Evaluation of Materials for the Design and Development of Sustainable Low-Cost Single-Use Electrode Leads for Wearable Medical Devices

Wearable medical devices have revolutionized continuous health monitoring, offering real-time data collection and enhanced patient care. Among the crucial components, electrode leads significantly influence bio-signal fidelity. However, their sustainability and affordability, especially as single-use items, pose notable challenges due to environmental concerns and cost implications. Screen-printed multilayer Single-Use Electrode Leads (SUEL) fabricated from environmentally friendly cellulose-based substrates, carbon-based ink materials, and compatible dielectric inks is one step towards sustainability. Material selection is based on set requirements for conductivity and biocompatibility. Selected paper substrates showed good tensile strength (3380-4367 psi), good yield strength (2250-2430 psi), and average maximum strain (3.0-4.4%). Also, carbon inks demonstrate good printability and feasibility for bio-signal data acquisition. Fabricated test vehicles without encapsulation showed sheet resistance of 14-16 Ω/sq/mil, while encapsulated test vehicles showed increased sheet resistance which was minimized by heat press treatment. Heat press treatment resulted in a noteworthy reduction in resistivity and a substantial decrease in contact resistance. Electromechanical tests reveal robust performance, with conductivity improving over bending cycles. Encapsulation studies and compatibility assessments ensure optimal material pairs for wearable devices.