Electrowetting-on-dielectric chip with integrated screen-printed electrochemical sensor for rapid chemical analysis

Abstract

In this work, a screen-printed electrochemical detector was fabricated on a digital electrowetting-on- dielectric (EWOD) microfluidic chip for the first time and employed for rapid chemical analysis. The digital microfluidic system consisted of a T-junction EWOD platform for merging buffer and analyte droplets and an electrochemical detector at the end of T-junction. The detector comprised three electrodes including carbon working, carbon counter and silver/silver chloride reference electrodes. The system was successfully fabricated by microfabrication and screen-printing processes and tested for electrochemical analyses of potassium hexacyanoferrate and hydrogen peroxide. The analyte and buffer droplets were controlled to mix with different concentrations and detected at the electrochemical detector using cyclic voltammetry. The results showed good detection performances with medium sensitivity, moderate detection limits, high stability and good reproducibility. In addition, the total analysis time including droplet mixing and CV measurement was shorter than 14 s. Therefore, the EWOD chip with integrated screen-printed carbon electrodes was a promising candidate for rapid automated chemical analysis.