Graphene digital microfluidics microchip

In this research, graphene digital microfluidics microchip was designed and fabricated by screen printing. The microchip was designed with electrowetting on dielectric as digital microfluidic microchip combine with electrochemical detector on single plate substrate. For the design, the chip consist of T-junction EWOD digital microfluidics microchip for merging buffer reagent and analyze droplets and an electrochemical detector at the end of T-junction EWOD. Both parts were fabricated by screen printed technique. The EWOD microchip consists of silver paste for electrodes layers and PDMS for dielectric and Teflon® AF hydrophobic layers. Three electrodes of electrochemical detector consists of a graphene-carbon paste working electrode and a graphene-carbon paste counter electrode, and silver/silver chloride paste reference electrode for rapid analysis with minimal reagent consumption. In experiment, the electrochemical detector combine with EWOD microchip was tested for electrochemical analysis with concentration of the reagent that were varied with 10, 50, 100, 250, and 500 μM with cyclic voltammograms. The results showed that the system was successfully tested for rapid analysis with minimal reagent consumption of ferri/ferrocyanide (Fe(CN)₆^3-/4-) and hydrogen peroxide (H₂O₂) with time was less than 20 seconds.