Screen Printed Graphene Carbon Paste Electrochemical Sensor for Lab on a Chip by Screen Printing

In this research, screen printed graphene carbon (SPGE) electrochemical sensing was designed and fabricated by screen printing for lab on a chip. Lab on a chip was designed with integrated single plate electrowetting on dielectric and electrochemical sensing on single plate substrate. For the design, lab on a chip consists of H-junction EWOD digital microfluidics microchip for merging buffer reagent and analyzed droplets and an electrochemical sensing at the end of T-junction EWOD. Both parts were fabricated by screen printed technique. Three electrodes of electrochemical sensing consist of a graphene-carbon paste working electrode, a graphene-carbon paste counter electrode, and silver/silver chloride paste reference electrode for high performance analysis. The EWOD microchip consists of silver paste for electrodes layers, PDMS for dielectric, and Teflon<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup>AF hydrophobic layers. In experiment, the electrochemical sensing integrate with EWOD microchip was designed to study possibility of samples (buffer and analyzed droplet) on the microchip. For analysis, the SPGE electrochemical sensing was analyzed for nicotinamide adenine dinucleotide for high performance analysis. The concentration of the reagent was varied with 10, 50, 100, 250, and 500 μM with cyclic voltammograms.