Fabrication of capacitive type biosensor based on CVD grown graphene

A capacitive type biosensor based on large-area multilayer graphene produced by chemical vapor deposition was fabricated in this work. Graphene film was transferred to cover indium tin oxides films which were used as one electrode of the capacitor. Planar Au film was on the top of the graphene substrate as the other electrode of the capacitor. Between the two electrodes, electrolyte with target molecules was injected as dielectric medium. Through changing the voltage on capacitor instantaneously, the dynamic response of the capacitor was detected by a homemade capacitor detecting system. Adenosine triphosphate (ATP) was selected as target molecules in this paper. Based on the dynamic response of the capacitor, ATP samples with concentration from 200 nM to 800 nM could be detected with good linearity. This work presentes a capacitive type biosensor based on graphene and maybe provide a new analytic method for biochemical molecules by graphene sensors.