Flexible and Transparent Agnws-Based Microelectrode Arrays and Interconnects for Multifunctional Electrical and Optical Biointerfacing

Abstract

Transparent microelectrode provides a promising approach combining electrophysiology and optogenetics for multi-functional biointerfacing. Flexible platforms with high performance which can achieve seamlessly integrating with soft tissue systems are highly needed. Herein, we demonstrate silver nanowires (Ag NWs)-based transparent microelectrode arrays (MEAs) and interconnects to meet this demand by using an innovative photolithography-based solution-processing technique. The resulting microelectrodes exhibit a high transparency of 76.1-90.0% over the visible spectrum, and low normalized electrochemical impedance of 3.4-15 Ω cm2 at 1 kHz which is comparable to that of opaque solid Ag films (12.4 Ω cm2). 93% transparency at 550 nm can be achieved through patterning the nanowire networks. Additionally, the microelectrodes possess excellent sheet resistance of 11-25 Ω sq−1, superior mechanical stability for 100,000 bending cycles at 5 mm radius, and chemical stability after 30-day soaking at 37 oC. In vivo histology study reveals the biocompatibility of the device. Studies on rat and transgenic mouse hearts show the ability of Ag NWs MEAs to optical mapping with negligible light-induced artifacts and real-time monitoring of heart rhythm under simultaneously optogenetic pacing with high-fidelity, respectively. This work illustrates that the Ag NWs-based platform can serve as a promising candidate for the next-generation of large-scale multi-functional biointerfaces for biological and biomedical research. Figure 1