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.