3D Microelectrodes for Coulometric Screening in Microfabricated Lab-on-a-Chip Devices

This paper presents results indicating the complete oxidation of an analyte using a three-dimensional, large surface area microelectrode in a lab-on-a-chip (LOC) device. Traditional photolithographic fabrication techniques were used to construct the microchip prototype, with the exception of the 3D electrodes. Experiments were performed using a flow-injection scheme, where a 1 mM sample of catechol was directed towards the detection reservoir. Oxidation voltage at a planar upstream electrode was increased from 0 to 1.2 V in 0.1 volt increments and was shown to reduce the detection level of the sample at a downstream planar electrode (1.2 V). Oxidation voltage at the upstream 3D electrode was changed in a similar manner and was shown to completely eliminate detection at a downstream planar electrode. These results indicate the complete removal of sample from the flow stream, suggesting that 3D micro fabricated electrodes could be used in an LOC device for coulometric screening