Detection of DNA-Hybridization Using Interdigitated Electrodes Functionalized with Graphene

Abstract

An array of four Au-IDEs was fabricated on Si/SiO2 and glass substrates. The active area of the fabricated IDEs has been functionalized with a GO layer using dielectrophoresis (DEP). The GO layer was reduced using L-Ascorbic Acid (L-AA). Finally, the surface of each rGO-IDE was functionalized with single-stranded DNA (ssDNA) molecules with perfectly matched or fully mismatched DNA-sequences to that of the complementary ssDNA (cDNA) molecules. For detection of the DNA hybridization and denaturation, the developed DNA-chip was mounted in a measurement cell and characterized by impedance spectroscopy (IS). The DNA hybridization and denaturation experiments were carried out in a differential IS setup using an impedance analyzer to eliminate the effect of disturbing factors in the sensor's signal. Changes in impedance for the sensors functionalized with perfect-matched ssDNA after a hybridization event were observed in contrast to almost no change when fully miss-matched ssDNA was used.