科研之友
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摘要
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 mu g L-1 to 200 mu g L-1, and its limit of detection (LOD) was 0.01 mu g L-1, which is superior to that of the SERS-Microfluidic Aptamer sensor (2.92 mu g L-1) and the Electrochemical Aptamer-MWNT/GC biosensor (3.42 mu g L-1). The Aptamer/Au biosensor was used to systematically screen four types of PCB congeners (i.e., PCB81, PCB126, and P0169) 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.
