Non-covalent binding of luminescent transition metal polypyridine complexes to avidin, indole-binding proteins and estrogen receptors

A number of luminescent transition metal complexes possess rich photophysical and photochemical properties that allow them to serve as useful labels and probes for biological molecules. This article describes the current trend in this area of research, with emphasis on our recent work on luminescent rhenium(I), iridium(III) and ruthenium(II) polypyridine complexes as non-covalent probes for avidin, indole-binding proteins and estrogen receptors. We focus on the molecular design, photophysical properties and biomolecule-binding behaviour of these systems; different approaches to enhancing the detection sensitivity are also discussed.