Fluorescent Turn-on Aptasensor ofStaphylococcus aureusBased on the FRET Between Green Carbon Quantum Dot and Gold Nanoparticle

This paper describes a novel strategy based on fluorescence energy transfer (FRET) with green synthesis of carbon quantum dots (CQDs) and gold nanoparticles (GNPs) for the detection of one of the most pathogenic bacteria,Staphylococcus aureus(S. aureus). Novel green CQDs with blue color emission and high quantum yield were synthesized from olive leaves via the hydrothermal method. The fluorescence of the CQDs was quenched in the presence of aptamers and GNPs. After addition of specific bacteria, the aptamer-target complex was formed and the emission of the free CQDs returned. The linear range of this aptasensor was 10(8)to 10(1) CFU/mL with a detection limit as low as 10 CFU/mL forS. aureus. The proposed aptasensing approach has been successfully used for the assay ofS. aureusin human serum, milk, and orange juice. Due to its simplicity and effectiveness, this system exhibits great promise as a practical aptasensor for the detection of other bacteria and biomolecules.