Flexible and Transparent Metal Nanowire Microelectrode Arrays and Interconnects for Electrophysiology, Optogenetics, and Optical Mapping

Transparent microelectrodes have recently emerged as a promising approach for crosstalk-free multifunctional electrical and optical biointerfacing. High-performance flexible platforms that allow seamless integration with soft tissue systems for such applications are urgently needed. Here, silver nanowires (Ag NWs)-based transparent microelectrode arrays (MEAs) and interconnects are designed to meet this demand. The nanowire networks exhibit a high optical transparency >90.0% at 550 nm, and superior mechanical stability up to 100,000 bending cycles at 5 mm radius. The Ag NWs microelectrodes preserve low normalized electrochemical impedance of 3.4–15 Ω cm² at 1 kHz, and the interconnects demonstrate excellent sheet resistance (R_sh) of 4.1–25 Ω sq⁻¹. In vivo histological analysis reveals that the Ag NWs structures are biocompatible. Studies on Langendorff-perfused mouse and rat hearts demonstrate that the Ag NWs MEAs enable high-fidelity real-time monitoring of heart rhythm during co-localized optogenetic pacing and optical mapping. This proof-of-concept work illustrates that the solution-processed, transparent, and flexible Ag NWs structures are a promising candidate for the next-generation of large-area multifunctional biointerfaces for interrogating complex biological systems in basic and translational research.