Bifunctional Silicon Quantum Dots for Antibacterial Application and Highly Sensitive Detection of Tetracycline

Silicon quantum dots (SiQDs) with high water-soluble and favorable photostability were prepared by a one-step hydrothermal method. The average diameter of SiQDs was 2.02 nm characterized by transmission electron microscope. It was to be noted that the as-prepared SiQDs showed effective antibacterial activity, which was attributed to electrostatic interaction and the generation of reactive oxygen species. The minimum inhibitory concentration of SiQDs against Escherichia coli and Staphylococcus aureus was 0.45 mg/mL and 0.38 mg/mL, respectively. Besides, based on the static quenching effect-induced fluorescence quenching mechanism, the SiQDs exhibited high sensitivity and selectivity for detecting tetracyclines (TC). A good linear relationship was obtained between the fluorescence intensity of SiQDs and the concentration of tetracycline (TC) in the range of 0–0.08 μmol/L ( R 2  = 0.9993) with a detection limit of 0.0176 μmol/L. Furthermore, the TC content in the honey samples was determined using the SiQDs. All the results suggest that the as-prepared SiQDs can be a potential fluorescent probe for application in antibacterial and analysis.