A Water-Soluble Fluorescent Probe for the Selective Sensing of Ag+ and its Application in Imaging of Living Cells and Nematodes.

In this study, an imidazole-coumarin based fluorescent probe was developed for the selective and sensitive detection of Ag+ in aqueous solution. Using a combination of Job plot, NMR titrations, and DFT calculations, the binding properties between Ag+ and the probe were deeply investigated, and the results revealed a 1:1 binding stoichiometry between the probe and Ag+ with a binding constant of 1.02 × 106 M-1. The detection limit was found to be 150 nM, which satisfies the requirement for the quantitative detection of Ag+ in real water samples. Moreover, the new probe, Ic, was successfully applied to sense Ag+ in HeLa and HepG2 cells as well as in C. elegans, indicating that it could be a useful tool for the environmental monitoring of Ag+ pollution. These results demonstrated that Ic could serve as a high-efficiency and low-cost fluorescent probe for tracking Ag+ in an aquatic environment and biological organisms.