K. J. Krause, K. Mathwig, B. Wolfrum and S. G. Lemay
Brownian motion in electrochemical nanodevices
The European Physical Journal Special Topics 223 (2014) 3156.
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Diffusion dominates mass transport in most electrochemical systems. In classical experimental systems on the micrometer scale or larger, this is adequately described at the mean-field level. However, nanoscale detection devices are being developed in which a handful or even single molecules can be detected. Brownian dynamics become manifest in these systems via the associated fluctuations in electrochemical signals. Here we describe the state of the art of these electrochemical nanodevices, paying particular attention to the role of Brownian dynamics and emphasizing areas in which theoretical understanding remains limited.

S. Sarkar, K. Mathwig, S. Kang, A. F. Nieuwenhuis and S. G. Lemay
Electrochemical Nanofluidic Assays in the Absence of Reference Electrode
Proceedings of the 18th International Conference on Miniaturized Systems for Chemistry and Life Science, San Antonio, USA, Oct. 26 – 30 (2014) 2122.
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Implementing a reliable reference electrode in miniaturized electrochemical sensors is challenging. Here, we present an alternative approach, based on redox cycling within a nanogap sensor consisting of two parallel electrodes, in which the reference electrode is omitted altogether. We show that on disconnection of the reference electrode, the solution potential floats to a certain value, which is explored theoretically and experimentally in order to quantitatively predict the potential. The obtained results are in good agreement with the theoretically reconstituted results.