Fluorescent switch for fast and selective detection of mercury (II) ions in vitro and in living cells and a simple device for its removal

A water-soluble, biocompatible, and fluorescent chemosensor (1) for label-free, simple, and fast detection of mercury ions (Hg2+) in aqueous solutions and in HepG2 cells with high selectivity is reported herein. Chelation of 1 with Hg2+ results in the disappearance of its fluorescence emission at 350 nm and the appearance of a new emission at 405 nm. Selectivity and interference studies indicated that 1 could be selectively chelated by Hg2+ without interference from other metal ions. Insight into the mechanisms responsible for its fluorescence effect was gained from ultrafast transient absorption spectroscopy. With these properties, 1 was successfully applied for imaging Hg2+ in living cells and for removing Hg2+ from river water. Moreover, we also constructed a simple device for fast and effective removal of Hg2+ from contaminated liquid samples.