Design and experimental study of electrochemical detector with EWOD for chemical analysis

In this work, we describe design and experimental studies of a electrochemical detector by using electrowetting on dielectric (EWOD) digital microfluidics microchip for chemical analysis. For the design, the electrochemical EWOD digital microfluidics system consists of T-junction EWOD microchip for merging buffer reagent and analyte droplets and three internal electrochemical detector at the end of T-junction. Three electrodes consist of Au working, Au reference, and Au auxiliary for rapid chemical analysis with minimal reagent consumption. In experiment, the single-plate EWOD microchip has been successfully fabricated and tested to study possibility of moving (merging and transporting) droplet on the microchip. For controlling droplet, we designed electrical circuits using a microcontroller to control relays that switching applied voltage to control electrodes on and off. Interfacing RS232 with microcontroller makes the droplet merging. Merging a droplet can be modified from personal computer by sending commands from a PC to a microcontroller. The tested results show that successfully move (merging) of deionized droplets along patterned single plate EWOD device by controlling of microcontroller.