A gold nanoparticle based immunosorbent bio-barcode assay combined with real-time immuno-PCR for the detection of polychlorinated biphenyls

A gold nanoparticle based bio-barcode assay combined with real-time immuno- polymerase chain reaction (PCR) was developed for the determination of polychlorinated biphenyls (PCBs). Gold nanoparticles modified with thiol-capped DNA and antibody for affixing probes were used to replace antibody-DNA conjugates in immuno-PCR. The modified gold nanoparticles were fixed on the PCR tube wall through a competitive immune reaction. Signal-DNA could be released from the gold nanoparticle surface into the tubes and used as template DNA. Real-time PCR was subsequently performed to directly quantify DNA signal. A detection limit of 2.55 pg L−1 was obtained under optimized conditions. This method was successfully used to detect Aroclor 1248 in Hairtail samples collected from the East China Sea near Zhejiang Province. Recovery values ranged from 84% to 104%, and the coefficient of variation (CV) was acceptable. Results were validated by GC-ECD, indicating that this convenient and sensitive method has great potential for trace PCBs screening in real environmental samples.