T. Šafarik, A. Karajić, S. Reculusa, P. N. Bartlett, N. Mano, A. Kuhn
Adv.Funct.Mater. 33 (2023) 2210638
Redox cycling (RC) is a powerful tool capable of amplifying faradaic currents in electroanalytical measurements, thus allowing an enhancement of sensitivity through fast multiple sequential oxidation and reduction reactions of a redox-active analyte. Present state-of-the-art RC devices are mostly based on planar electrode geometries either in 2D or 3D configurations, requiring cleanroom facilities and expensive microfabrication techniques. Here, we report the electrochemical elaboration and characterization of a three-dimensional coaxial macroporous twin-electrode, obtained by following a low-cost bottom-up approach. A nanoengineered highly organized porous material is the bases for the design of two threaded cylindrical porous gold microelectrodes with a gap in the micrometer range that can be fine-tuned. The potentials of the outer and inner electrodes are biased at values above and below the redox potential of the analyte so that a given molecule can participate several times in the electron exchange reaction by shuttling between both electrodes. The resulting signal amplification, combined with a straightforward synthesis strategy of the electrode architecture allows envisioning numerous (bio)electroanalytical applications.
