Redox cycling in nanofluidic channels using interdigitated electrodes
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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.
KeywordsNanotechnology Nanofluidic Electrochemistry Amperometric detection Redox cycling Interdigitated electrodes (IDEs) Paracetamol Ascorbic acid Sensor
This work was funded by the NanoNed and NWO. Edgar Goluch would like to thank the U.S. National Science Foundation for support through IRFP Grant Number 0754396. Bernhard Wolfrum was funded by the DFG. We acknowledge Cees Dekker for general support and helpful discussions.
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