Smartphone-assisted ratiometric FRET aptasensor based on quantum dots and gold nanoparticles for point-of-care testing of zearalenone in cereals

Herein, a ratiometric fluorescence aptasensor was established for zearalenone (ZEN) detection based on fluorescence resonance energy transfer (FRET) between aptamer-modified CdTe quantum dots (QDs) as donor and gold nanoparticles (AuNPs) as acceptor. The fluorescence of CdTe QDs quenched by AuNPs based on FRET, while Si QDs with blue fluorescence as reference. The aptamer-modified CdTe QDs were adsorbed to ZEN in the presence of ZEN, and the distance between the energy receptor and the donor increased, which prevented the FRET and led to the fluorescence recovering of CdTe QDs. The aptasensor exhibited a limit of detection of 3.5 pg/mL with a linear range of 0.01–100 ng/mL. In addition, a portable detection device was constructed by integrating with smartphone for point-of-care testing (POCT) of ZEN with satisfactory results, which could provide a promising application for visual POCT of ZEN in cereals.