A novel electrochemical PCB77-binding DNA aptamer biosensor for selective detection of PCB77

• A PCB77-binding DNA aptamer modified Au electrode was developed for rapid detection of PCB77.
• The Aptamer/Au biosensor demonstrated a linear response with PCB77 concentrations, and lower limit of detection.
• The Aptamer/Au biosensor could differentiate PCB77 from potential co-existing PCB congeners.
• It is a potential tool for selective and rapid determination of PCB77 on site.

3,3′4,4′-Polychlorinated biphenyl (PCB77) is a structurally coplanar PCB that causes cancer and other adverse health effects. In this study, an electrochemical biosensor based on a DNA-aptamer-modified Au electrode (Aptamer/Au) was developed for the rapid detection of PCB77 with high selectivity. This PCB77-binding DNA aptamer isolated by SELEX (systematic evolution of ligands by exponential enrichment) and a 3′-DNA aptamer modified with electroactive ferrocene (Fc) were used as the biorecognition element and signal amplification molecules, respectively, for the determination of PCB77 with high selectivity and sensitivity. The Aptamer/Au biosensor demonstrated a linear response with PCB77 concentrations ranging from 0.2 μg L− 1 to 200 μg L− 1, and its limit of detection (LOD) was 0.01 μg L− 1, which is superior to that of the SERS-Microfluidic Aptamer sensor (2.92 μg L− 1) and the Electrochemical Aptamer-MWNT/GC biosensor (3.42 μg L− 1). The Aptamer/Au biosensor was used to systematically screen four types of PCB congeners (i.e., PCB81, PCB126, and PCB169) and chlorinated benzene (i.e., chlorobenzene, 1,2,3-trichlorobenzene and pentachlorobenzene). The results showed that the Aptamer/Au biosensor could differentiate PCB77 from potential co-existing interferents (i.e., PCB congeners and benzene derivatives). Therefore, this sensor is a potential tool for the selective and rapid on-site determination of PCB77.

Graphical AbstractSchematic diagram of the Aptamer/Au biosensor detection of PCB77 by DPV.Figure optionsDownload as PowerPoint slide