Facile synthesis of highly efficient fluorescent silicon quantum dots used for highly sensitive sensor of tetracycline in honey samples and antibacterial agent.

The excessive use of antibiotics and the presence of tetracycline (TC) residues poses a significant threat to human health. It is imperative to develop antibacterial materials which address the issue of bacterial resistance as well as to establish reliable methods for detecting TC to ensure food safety. This study reports the synthesis of silicon quantum dots (SiQDs) with blue fluorescence emission at 420 nm via a hydrothermal method, using allyloxytrimethylsilane, triacetoxy(methyl)silane as the silicon sources and sodium citrate as a reducing agent. The synthesized SiQDs demonstrated remarkable photostability in 60 min of UV irradiation as well as pH-stability across a range from 2.09 to 11.92. They exhibited salt tolerance and anti-oxidant capacity, even when the concentrations of NaCl and HO were up to 4 mol/L and 1000 μmol/L, respectively. Notably, the SiQDs displayed efficient antibacterial activity without resistance by electrostatic interaction and excessive production of reactive oxygen species (ROS), which would damage the bacterial cell walls and subsequently inhibit bacterial growth and reproduction. The minimum inhibitory concentration of SiQDs was 0.45 mg/mL against Escherichia coli and 0.25 mg/mL against Staphylococcus aureus, respectively. Besides, a fluorescence nanoprobe based on SiQDs was meaningfully constructed to sensitively and rapidly determine TC owing to the internal filtration effect. The limit of detection for SiQDs to TC was 0.0006 μmol/L with a linear range from 0.001 to 0.010 μmol/L. The probe's practicality was confirmed in spiked honey samples from different manufacturers with an approximate 100 % recovery of TC. Consequently, this research presents a promising avenue for enhancing the detection of TC in food safety and the development of antibacterial agents without bacterial resistance.