Chromofluorescent Indicator for Intracellular Zn2+/Hg2+ Dynamic Exchange

The fluorescence of NABQ increases remarkably in the presence of Zn2+ and is quenched by Hg2+. As shown by confocal imaging, NABQ−Zn2+ can penetrate cells, where the bound Zn2+ is exchanged for Hg2+. This results in the concomitant export of Hg2+ from the cells, showing that NABQ can act as a Zn2+ carrier and as a Hg2+ extracting agent in living cells.