Direct Electrical Detection of DNA Hybridization Based on Electrolyte-Gated Graphene Field-Effect Transistor

DNA hybridization was electrically detected by graphene field-effect transistors. Probe DNA was modified on the graphene channel by a pyrene-based linker material. The transfer characteristic was shifted by the negative charges on the probe DNA, and the drain current was changed by the full-complementary DNA while no current change was observed after adding noncomplementary DNA, indicating that the graphene field-effect transistor detected the DNA hybridization. In addition, the number of DNAs was estimated by the simple plate capacitor model. As a result, one probe DNA was attached on the graphene channel per 10 x 10nm(2), indicating their high density functionalization. We estimated that 30% of probe DNA on the graphene channel was hybridized with 200nM full-complementary DNA while only 5% of probe DNA was bound to the noncomplementary DNA. These results will help to pave the way for future biosensing applications based on graphene FETs. (C) 2013 The Japan Society of Applied Physics