Gold Nanoparticles dotted Reduction Graphene Oxide Nanocomposite Based Electrochemical Aptasensor for Selective, Rapid, Sensitive and Congener-Specific PCB77 Detection

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.