This talk will focus on electrochemical sensing with a single Au nanowire (NW) suspended in the center of a microfluidic channel such that the entire 3D surface-area is contact with continuous phase. The NWs were fabricated by nanoskiving, enabling facile preparation of millimeter-long wires via edge lithography. Suspending the detection element directly in the center of a microchannel facilitates most direct sensing due to immediate analyte transport. Moreover, signal amplification is higher compared to nanowires positioned at a channel wall. The current of CVs recorded with a single suspended NW increases with the rate of flow and the wire also functions as a hot-wire anemometr. The increase in CV current is sublinear and monotonic, as is the case for conventional microelectrodes. The limiting current levels off at comparatively low rates of flow due to highly efficient mass transport of ferrocene to the wire in the <i>center</i> of the channel. Even at stagnant flow the detected current is approximately 60% larger as compared to a nanowire placed at the bottom of the microchannel. This is the first report of suspended nanowires in a microchannel being used for electrochemical voltammetry under flow. The method opens up new possibilities for the integration of nanosized sensors in the center of the flow profile in microfluidic channels, thus enabling fast and accurate sensing.

Electrochemical sensing with a suspended single nanowire in a microfluidic channel

255th National Meeting (2018)

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