Aptamer-quantum dots and teicoplanin-gold nanoparticles constructed FRET sensor for sensitive detection of Staphylococcus aureus

The detection of bacterial pathogen such as Staphylococcus aureus (S. aureus) is essential for the regulation of food hygiene and disease diagnosis. Herein, we developed a simple one-step fluorescence resonance energy transfer (FRET)-based sensor for specific and sensitive detection of S. aureus in food and serum samples, in which aptamer-modified quantum dots (aptamer-QDs) was employed as the energy donor and antibiotic of teicoplanin functionalized-gold nanoparticles (Teico-AuNPs) was chosen as the energy acceptor. Within 1 h, the FRET-based sensor showed a linear range of from 10 cfu/mL to 5 × 108 cfu/mL, with the low limit of detection (LOD, 2 cfu/mL) for S. aureus in buffer. When further applied to assay S. aureus in real samples, the FRET-based sensor showed good recoveries ranging from 84.5% to 110.0%, with relative standard derivations (RSDs) of 0.01%–0.44% and a LOD of 100 cfu/mL in milk, orange juice and human serum.