Biological labelling reagents and probes derived from luminescent transition metal polypyridine complexes

Many transition metal polypyridine complexes display intense and long-lived metal-to-ligand charge-transfer emission with a large Stokes’ shift. This property renders them promising candidates as luminescent labelling reagents and probes for biological molecules. In view of this, we have designed various biological labels that are derived from luminescent rhenium(I) and iridium(III) polypyridine complexes. These complexes contain various functional groups that can react with the amine and sulfhydryl groups of biomolecules such as oligonucleotides, peptides and protein molecules to form luminescent bioconjugates. In other studies, we have incorporated biotin into luminescent rhenium(I) polypyridine complexes to form new probes for the protein avidin. These new luminescent conjugates and biological probes have been utilised in the development of various bioassays.