Amplification of fluorescence polarization signal based on specific recognition of aptamers combined with quantum quenching effect for ultrasensitive and simple detection of PCB-77

Abstract

Here, we report a novel aptasensor based on decahedral silver nanoparticles (Ag₁₀NPs) enhanced fluorescence polarization (FP) for detecting PCB-77. Using aptamer modified Ag₁₀NPs hybridized with DNA sequence labeled fluorescent group as an analytical probe, polychlorinated biphenyls (PCB-77) could be detected with high sensitivity and selectivity. The linear range of determination was 0.02 ng/L to 390 ng/L and the limit of detection was 5 pg/L. In addition, through the optimization of the experiment condition and signal probe DNA (pDNA), we found that the maximum FP signal could be generated when the distance between fluorescein and the surface of Ag₁₀NPs was 3 nm. When the aptamer was immobilized on the surface of Ag₁₀NPs could be strengthened the anti-interference performance of aptamer nanoprobe and further improved the detection ability. At the same time, we also compared the detection performance of the traditional FP signal enhancer streptavidin (SA) analysis system. The fluorescence polarization aptasensor could detect PCB-77 samples efficiently in complex environmental water, which shows a good application prospect.

Keywords: Aptamer; Fluorescence polarization; Nanoprobe; PCB-77; Silver decahedral nanoparticles.