Mapping biocurrents at microsecond resolution at the single cell resolution requires the combination of optical imaging with innovative electrophysiological sensing techniques. Recently we developed transparent electrophysiology electrodes and interconnects made of gold (Au) nanomesh on flexible substrates to achieve such measurements. Compared to previously demonstrated indium tin oxide (ITO) and graphene electrodes, the ones from Au nanomesh possesses superior properties including low electrical impedance, high transparency, good cell viability, and superb flexibility. Specifically, we demonstrated a 15 nm thick Au nanomesh electrode with 8.14 Ω.cm2 normalized impedance, &gt;65% average transmittance over a 300 nm to 1100 nm window, and stability up to 300 bending cycles. To enable scaling of metal nanomesh microelectrodes to single cell size, we further demonstrated an innovative bilayer nanomesh approach while preserving the nanomesh advantage. Through electroplating of low-impedance coatings on gold nanomesh templates, we achieved impedance of ~30 kΩ and charge injection limit over 1 mC/cm2 for 80×80 µm2 microelectrodes, a 3.7× and 12.8× respective improvement compared to without coatings, while with similar transparency of ~70%. Systematic sheet resistance measurements, electrochemical impedance studies, optical characterization, mechanical bending tests, and cell studies highlight the capabilities of single and bi-layer nanomesh as a new transparent electrophysiology electrode and interconnect material. Together, these results set the stage for using nanomeshes under biological conditions and broad applications in biology and medicine.

Functional multilayer nanomeshes for advanced bio-recording and stimulating microelectrodes

256th National Meeting (2018)

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