Dual-functional near-infrared Ag₂S quantum dots nanoprobes: Erythromycin detection and bio-imaging

In this study, near-infrared (NIR) Ag₂S quantum dots (QDs) nanoprobes were successfully synthesized via a one-pot method. The Ag₂S QDs nanoprobes have an average size of approximately 3.3 nm and are uniformly dispersed. These nanoprobes exhibit an emission wavelength is at 810 nm and can specifically detect erythromycin (ERY). At pH 5.0, The fluorescence intensity of Ag₂S QDs nanoprobes shows a linear response within the ERY concentration range of 0.10-0.40 μM, with a detection limit (LOD) of 0.096 μM and a detection time of 5 min. Furthermore, the nanoprobes were applied to detect ERY in milk samples. To evaluate the biosafety of the Ag₂S QD nanoprobes, cell assays, hemolysis tests, and hematoxylin-eosin (HE) staining of tissue sections were performed. The results indicate that the nanoprobes exhibit negligible toxicity toward HepG2 and LO2 cells, good compatibility with red blood cells (RBCs), and no damage to organs or tissues. Additionally, the nanoprobes were successfully used for in vitro cellular imaging and in vivo imaging in mice. Therefore, the Ag₂S QD nanoprobes show great potential for applications in drug detection, bioimaging, and clinical diagnosis.