A new quinoline-based fluorescent probe for Cd(2+) and Hg(2+) with an opposite response in a 100% aqueous environment and live cell imaging.

A new quinoline-based fluorescent probe was synthesized and characterized. Probe showed opposite fluorescence responses toward Cd(2+) (turn-on) and Hg(2+) (turn-off) in a 100% aqueous environment. X-ray crystallography analysis and TD-DFT calculations showed the different mechanisms of CHEF-based for -Cd(2+) and PET-based for -Hg(2+) caused by different binding modes and different electronic transfer patterns. The detection limits for the analysis of Cd(2+) and Hg(2+) ions were found to be 3.9 × 10(-8) M and 9.8 × 10(-7) M, respectively. Its in vivo sensitivities to Cd(2+) and Hg(2+) were demonstrated in the EC9706 cell line with the use of a laser scanning fluorescence microscope.