Microchannel Integrated Comb-Type Electrode System for Electrochemical Detection

This paper describes a microchannel integrated comb-type electrode with teeth to induce serpentine flow. The configuration has led to obviate the step of assembling a microchannel because the gap between the positive and negative working electrodes actually forms a channel. Moreover, interdigitated tooth structure on the walls at each side of the channel causes turbulent flow effect in the sample flow. This behavior promotes oxidation-reduction reactions which enhances the sensitivity of the electrodes. We developed gold-coated nickel electrodes by electroless gold plating after nickel electroplating. The microchannel was 50 mum in width, 30 mum in height, and 1.5 mm in length. The PDMS plate was bonded on the diced devices by plasma treatment to set a flow system. The mold was made on the same wafer to have the same height with the electrodes. Forty-micrometer tooth electrode showed about twice enhanced efficiency over 10 mum-tooth electrode.