Highly Transparent Metal Nanowire Microelectrodes for Simultaneous Electrophysiology and Optophysiology
Open AccessElectrophysiology has remained the principal technique for measuring and understanding physiological activity in a wide variety of biological applications. Cell specific characterizations rely on reliable microscale recording networks; however, the standard electrophysiological recording technology lacks precise information on which cell populations contribute to measured signals. The advent of optogenetics within the last two decades has enabled new methods that allow highly specific modulative cell control via light-gated ion channels. With these advances in optics and genetics, there has been sparked research interest in device technology that enable simultaneous activation and observation of targeted proteins with high spatiotemporal fidelity. Standard microelectrode arrays create a fundamental challenge for optical integration as the opaque metal generates optical shadows between tissues and light sources. In addition, severe light-induced electrical artifacts from opaque metal electrodes distort the recorded signals. Transparent conducting electrodes (TCEs) present a solution to this problem by enabling efficient light delivery through the electrodes for co-localized optogenetics and electrophysiology. Traditionally, doped metallic oxides such as indium tin oxide (ITO) are used for a variety of optoelectronic applications due to their high electrical conductivity and high optical transparency. However, they are prone to numerous mechanical deficiencies and are a relatively expensive material. Other materials that have been explored as potential substitutes have their own drawbacks in performance and transmittance. In this paper, we present silver nanowire based microelectrodes and interconnects on flexible substrates as a facilitative optogenetic bio-interface. Compared to other TCEs, silver nanowires possess superior properties including low electrical impedance, high transparency, and exceptional mechanical flexibility. Specifically, we demonstrate a base nanowire film with normalized impedance of 7.2 Ω cm2 and transparency of 65%. Using photolithography, the nanowire electrodes can be further patterned into a grid structure with varying dimensions that give a normalized impedance range of 14.3 Ω cm2 – 68 Ω cm2 and transmittance from 77 – 94%. The nanowire recording electrodes also show excellent flexible stability, showing no significant deterioration in performance after 2000 bending cycles. Systematic optical characterizations reveal negligible light-induced artifacts and ex vivo bio recording highlight the nanowire electrode as an effective transparent recording electrode alternative. Together, this work provides a versatile approach for constructing flexible bioelectronic interfaces with potential for both electrical and optical interrogation of bioelectrical signals in a broad range of biomedical applications
- All rights reserved
Notice to Authors
If you are the author of this work and you have any questions about the information on this page, please use the Contact form to get in touch with us.
| Thumbnail | Title | Date Uploaded | Visibility | Actions |
|---|---|---|---|---|
|
|
Boyajian_gwu_0075M_14947.pdf | 2019-12-17 | Open Access |
|