Transparent and Stretchable Au─Ag Nanowire Recording Microelectrode Arrays

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Transparent microelectrodes enable simultaneous electrical and optical monitoring of biological activity.
• Existing transparent microelectrodes face challenges in achieving mechanical stretchability, optical transparency, electrochemical performance, and chemical stability for soft tissue interfacing.

Purpose of the Study:

• To design and fabricate novel transparent microelectrode arrays (MEAs) with enhanced properties for biomedical applications.
• To address the limitations of current transparent microelectrodes in terms of stretchability, transparency, and stability.

Main Methods:

• Development of microelectrode arrays (MEAs) using gold-coated silver nanowires (Au─Ag NWs).
• Characterization of MEAs for optical transparency, electrochemical impedance, chemical stability, and electromechanical performance under cyclic stretching.
• Evaluation of MEA conformability to curvilinear surfaces for cardiac mapping.

Main Results:

• MEAs achieved >80% optical transparency at 550 nm and low normalized 1 kHz electrochemical impedance (1.2-7.5 Ω cm²).
• The gold coating enhanced chemical stability and reduced electrochemical impedance.
• MEAs demonstrated stable performance after oxygen plasma exposure and 600 cycles of 20% strain stretching.
• MEAs conformed to curved surfaces for simultaneous electrophysiological and optical mapping of cardiac function.

Conclusions:

• Stretchable transparent Au─Ag NW MEAs offer a promising solution for high-fidelity, conformal interfacing with soft tissues.
• These MEAs exhibit superior performance compared to existing alternatives, particularly for dynamic mechanical conditions.
• The developed MEAs are suitable for diverse biomedical science and engineering applications, including cardiac monitoring.