Thiourea-Based Fluorescent Chemosensors for Aqueous Metal Ion Detection and Cellular Imaging

We describe three significant advances in the use of thioureas as reporting elements for metal-responsive fluorescent chemosensors. First, on the basis of the crystal structure of a chemosensor analogue, we provide a deeper understanding of the details of the thiourea coordination environment. Second, we describe a new generation of chemosensors with higher affinities for Zn2+ and Cd2+ than were observed for earlier probes, expanding the scope of this type of probe beyond Hg2+ detection. Third, we show that a thiourea-based chemosensor can be employed for fluorescence microscopy imaging of Hg2+ ion concentrations in living mammalian cells.