Gold Nanoparticles dotted Reduction Graphene Oxide Nanocomposite Based Electrochemical Aptasensor for Selective,...

Gold nanoparticles (AuNP) dotted reduction graphene oxide (RGO-AuNP) is used as a platform for an aptamer biosensor to selectively detect 3,3'4,4'-polychlorinated biphenyls (PCB77). By anchoring aptamers onto the binding sites of RGO-AuNP and making use of the synergy effect of RGO and AuNP, the RGO-AuNP based biosensor exhibits superior analytical performances to AuNP based biosensor in terms of sensitivity and repeatability. The sensitivity of RGO-AuNP based aptamers (RGO-AuNP-Ap) biosensor (226.8 μA cm^-2) is nearly two times higher than that of Au based biosensors (AuNP-Ap/Au electrode, 147.2 μA cm^-2). The RGO-AuNP-Ap/Au biosensor demonstrated a linear response for PCB77 concentrations between 1 pg L^-1 and 10 μg L^-1, with a low limit of detection (LOD) of 0.1 pg L^-1. The superb LOD satisfies the exposure thresholds (uncontaminated water < 0.1 ng L^-1) set out by International Agency for Research on Cancer (IARC) and the Environmental Protection Agency (EPA). The proposed biosensor can be a powerful tool for rapid, sensitive and selective detection of PCBs on site.