In this study, we design an extremely fast and sensitive immunosensing platform using graphene as the sensing platform. A solution containing a mixture of graphene nanoplatelets and gold nanoparticles was coated on to a copier paper using a spray gun to form a uniform coating. Fluorescent quantum dots (QDs) functionalized with antibodies (Ab) were drop casted on to this platform, whose fluorescence was quenched by the graphene on the graphene/gold paper. With the addition of the antigen to this graphene/gold-QD-Ab complex, a disruption of quenching was observed, and the fluorescence intensity increased with increasing concentration of the antigen. A detection limit of as low as 10 fM was obtained for the detection of human Immunoglobulin G (IgG)
