Journal of Electroanalytical Chemistry, Vol.840, 67-73, 2019
Fabricating photoelectrochemical aptasensor for sensitive detection of aflatoxin B-1 with visible-light-driven BiOBr/nitrogen-doped graphene nanoribbons
A selective and sensitive photoelectrochemical (PEC) aptasensor for AFB, detection in corn samples was fabricated by introducing BiOBr/nitrogen-doped graphene nanoribbons (N-GNRs) as photoactive interface. As efficient visible-light-driven photoactive species, the prepared BiOBr/N-GNRs exhibited higher photoactivity than pure materials under visible light irradiation. N-GNRs, acting as promising supporters for nanomaterials, can improve the performance of composites. UV-vis diffuse reflectance spectroscopy demonstrated that BiOBr/N-GNRs possessed the narrower band gap energy, which could be easily irradiated by visible light. In addition, steady-state photoluminescence (PL) spectra also revealed that BiOBr/N-GNRs exhibited the lower recombination rate of photogenerated electron-hole pairs. The formation of the aptamer-AFB(1) complex increased the resistance of the electrode, restrained the electron transfer, and thus quenched the PEC signal. Thereafter, a "signal-off" PEC aptasensor was fabricated successfully. The proposed PEC aptasensor demonstrated sensitive detection of AFB(1) in a wide range from 5 pg mL(-1) to 15 ng mL(-1) with a low detection limit of 1.7 pg mL(-1) and possessed high specificity and good reproducibility. The PEC aptasensor was suitable for corn samples with a good recovery in the range of 98.0-102.0% and the relative standard deviation (RSD) of 1.7-2.1% to confirm practical utility. Furthermore, this strategy would be extended to detect different targets as versatile PEC devices by replacing the aptamers with other sequences.