A sensitive and accurate fluorescent genosensor for Staphylococcus aureus detection

Pathogenic bacteria, as a major cause of foodborne diseases, pose a serious threat to human health, which urges the development of sensitive and accurate detection methods. Herein, a fluorescent genosensor was designed for Staphylococcus aureus (S. aureus) detection based on fluorescent probes and graphene oxide quantum dots (GOQDs). The π-π stacking and hydrogen bond interactions between GOQDs and specific single-stranded DNA (ssDNA) of the fluorescent probes were exploited by the developed genosensor. The interactions brought the GOQDs to the surface of the fluorescent probes, quenching strong upconversion fluorescence. However, the hybridization of the recognition probes anchored on the fluorescent reporters with complementary nuc target obstructed the interactions, causing the fluorescence to gradually increase with the increasing concentration of complementary nuc target. Consequently, the target-specific sensor exhibited high sensitivity with a LOD of 0.98 × 10−17 mol L−1 and a linear range from 1 × 10−17 to 1 × 10−11 mol L−1. Moreover, the genosensor was successfully applied for real sample analysis with excellent recoveries. Significantly, the sensor could be used for the detection of other pathogens in actual samples by replacing recognition probes and primers.