Chromofluorescent indicator for intracellular Zn²⁺/Hg ²⁺ dynamic exchange

(Chemical Equation Presented) (Figure Presented) 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 Hg ²⁺. 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.