Employing CuInS2quantum dots modified with vancomycin for detecting Staphylococcus aureusand iron(iii)Electronic supplementary information (ESI) available. See DOI: 10.1039/d0ay02253e

This paper describes a near-infrared quantum dot (CuInS2QD)/antibiotic (vancomycin) nanoparticle-based assay for the Staphylococcus aureusand iron(iii) detection. CuInS2QDs 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 aureusis mainly the fluorescence quenching caused by the accumulation of CuInS2@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. aureusand the Fe3+ion is 103to 108CFU mL−1and 10–90 μM, respectively. Their detection limits are 665 CFU mL−1and 3.5 μM, respectively. The procedure was validated by the quantitation of Staphylococcus aureusand iron(iii) in spiked samples, and was found to demonstrate the feasibility of this method.