Inner filter effect-modulated ratiometric fluorescence aptasensor based on competition strategy for zearalenone
Xiaoya Bi1, Libo Li1, Xiaohong Liu1
1Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
Abstract:
Herein, an innovative ratiometric fluorescence (FL) aptasensor was successfully fabricated for the accurate analysis of zearalenone (ZEN) in corn and barley flour. The ZEN aptamer-modified nitrogen doped graphene quantum dots (NGQDs-apt) and silica sphere-encapsulated cadmium telluride quantum dots (CdTe QDs@SiO2) were directly mixed and applied as ratiometric probes. In the absence of ZEN, mitoxantrone (MTX), which was innovatively introduced as quencher, was captured by NGQDs-apt and its inner filter effect (IFE) on CdTe QDs@SiO2 was inhibited. When ZEN existed, MTX separated from NGQDs-apt and re-dispersed around CdTe QDs@SiO2 owing to the competitive binding of ZEN with its aptamer. As the IFE of free MTX on CdTe QDs@SiO2 recovering, the FL intensity of CdTe QDs@SiO2 was quenched, while the FL intensity of NGQDs-apt was nearly invariant. On this basis, a ratiometric FL aptasensor for ZEN was fabricated, which exhibited outstanding detection performances with a desirable detection limit of 0.32 pg mL-1.
