A fluorescence immunoassay based on CdTe : Zn/ZnS quantum dots for the rapid detection of bacteria, taking CM'13 as an example.

A fluorescence immunoassay has been widely applied in different fields due to its high sensitivity, simple operations, and high accuracy. Quantum dots (QDs) are often selected as labels in a fluorescence immunoassay due to their high fluorescence, better stability, and biocompatibility. In this study, novel doped CdTe : Zn/ZnS QDs with stability and a high photoluminescence quantum yield (40.78%) were prepared by the water synthesis method and used as labels to conjugate with goat anti-rabbit IgG to establish a fluorescence immunoassay (FLISA) for bacteria compared to the traditional enzyme-linked immunosorbent assay (ELISA) based on the reaction between an antibody and an antigen. A good linear relationship between the fluorescence intensity and concentrations of CM13 was found when the concentrations were in the range of 10 CFU mL-10 CFU mL. The limit of detection (LOD) of CM13 was 1.25 × 10 CFU mL by FLISA, which was about 80 times lower than the LOD obtained from ELISA (10 CFU mL). This indicated that our FLISA method has higher sensitivity than traditional ELISA, and the CdTe : Zn/ZnS QDs synthesized in this paper have good applications in the rapid sensitive detection of microorganisms.