A system composed of vanadium(IV) disulfide quantum dots and molybdenum(IV) disulfide nanosheets for use in an aptamer-based fluorometric tetracycline assay.

A system composed of vanadium(IV) disulfide quantum dots (VS2 QDs) and molybdenum(IV) disulfide (MoS2) nanosheets for use in an aptamer-based fluorometric tetracycline assay was developed. The tetracycline (TET) aptamer was first immobilzed on the VS2 QDs with a typical size of 3 nm. The blue fluorescence of the VS2 QDs (labeled with aptamer) with emission maxima at 448 nm (under excitation at 360 nm) was subsequently quenched by MoS2 nanosheets. If TET is recognized by the aptamer, the VS2 QDs drift away from the basal plane of the MoS2 nanosheets. This generated "turn-on" fluorescence of the VS2 QDs. A VS2 QD/MoS2 nanosheet-based fluorometric TET aptasensor was thus constructed. Selective and sensitive TET bioanalysis was realized in a linear range of 1 to 250 ng mL-1. The detection limit was 0.06 ng mL-1. Its applicability of determination of TET in milk samples has been demonstrated. Graphical abstractSchematic representation of the aptamer-based fluorometric tetracycline assay.