Employing CuInS quantum dots modified with vancomycin for detecting Staphylococcus aureus and iron(iii).

This paper describes a near-infrared quantum dot (CuInS QD)/antibiotic (vancomycin) nanoparticle-based assay for the Staphylococcus aureus and iron(iii) detection. CuInS QDs with good biological tissue permeability and biocompatibility are combined with vancomycin through covalent interaction to form a detection system for two harmful factors. The detection principle of Staphylococcus aureus is mainly the fluorescence quenching caused by the accumulation of CuInS@Van QDs on the surface of Staphylococcus aureus. The detection principles of the iron(iii) ion are mainly ascribed to the aggregation of quantum dots and the transfer of charges, which cause the fluorescence signal to change. The linear range of S. aureus and the Fe ion is 10 to 10 CFU mL and 10-90 μM, respectively. Their detection limits are 665 CFU mL and 3.5 μM, respectively. The procedure was validated by the quantitation of Staphylococcus aureus and iron(iii) in spiked samples, and was found to demonstrate the feasibility of this method.