A Ratiometric Fluorescence Probe Based on Silver Nanoclusters and CdSe/ZnS Quantum dots for the Detection of Hydrogen Peroxide by Aggregation and Etching

In this study, a ratiometric fluorescence nanoprobe is developed for the analysis of hydrogen peroxide (H 2 O 2 ). Silver nanoclusters (AgNCs) were synthesized by chemical reduction method using sodium borohydride (NaBH 4 ) as reducing agent, and were coupled with CdSe/ZnS quantum dots (QDs) to form the ratiometric fluorescence nanoprobe silver nanoclusters-quantum dots (AgNCs-QDs). The effect of the volume ratio of CdSe/ZnS QDs to AgNCs on the fluorescence ratio of AgNCs-QDs was investigated. The fluorescence characterization results show that two emission peaks of AgNCs-QDs are located at 473 nm and 661 nm, respectively. Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) results show that H 2 O 2 can cause the fluorescence probe to aggregate, while etching AgNCs to produce silver ions, which together cause the fluorescence of the QDs in the ratiometric fluorescent probe to be quenched. Based on this strategy, the fluorescence intensity ratio of the two emission peaks F 473 /F 661 exhibits a strong linear correlation with the concentration of H 2 O 2 . The detection range is 3.32 µM ~ 2.65 mM with a detection limit of 3.32 µM. In addition, the ratiometric fluorescence probe can specifically recognize H 2 O 2 and has excellent anti-interference performance and good fluorescence stability. Importantly, the probe was utilized for the detection of H 2 O 2 in serum, showing the possibility of the probe in clinical detection applications.