Redox cycling in nanofluidic channels using interdigitated electrodes

Abstract

Amperometric detection is ideally suited for integration into micro-and nanofluidic systems as it directly yields an electrical signal and does not necessitate optical components. However, the range of systems to which it can be applied is constrained by the limited sensitivity and specificity of the method. These limitations can be partially alleviated through the use of redox cycling, in which multiple electrodes are employed to repeatedly reduce and oxidize analyte molecules and thereby amplify the detected signal. We have developed an interdigitated electrode device that is encased in a nanofluidic channel to provide a hundred-fold amplification of the amperometric signal from paracetamol. Due to the nanochannel design, the sensor is resistant to interference from molecules undergoing irreversible redox reactions. We demonstrate this selectivity by detecting paracetamol in the presence of excess ascorbic acid.

Development of Interdigitated Array Electrodes with Surface-enhanced Raman Scattering Functionality

“…[14][15][16] However, electrochemical methods are not fruitful for analyzing the mixtures of electroactive species because of the additive diffusion fluxes of the components. 17 In addition, these techniques can rarely detect short-lived transients and predict their molecular structures.…”

Electrochemical random-walk theory

“…Simulation is performed either with the collector electrode electroactive to drive the oxidation of B, or with it as an insulator, so no reaction occurs. This is similar to the redox cycling method by Goluch et al [34] and Zevenbergen et al [35], who have created dual channel electrode systems to take advantage of the different diffusion layer as compared to the cylindrical space case. Preparation for a random-walk simulation takes the following steps.…”

Differential cyclic voltammetry - a novel technique for selective and simultaneous detection using redox cyling based sensors

“…With such an electrode a RC amplification of up to ~65 times is reported in bulk [2]. An amplification of 100 times is reported for IDEs used in nanochannels [23]. Zevenbergen et al [24] fabricated a device with two parallel, nanometer-spaced electrodes which resulted in an even higher RC amplification factor of ~400 times.…”