Luminescence switch-on assay of interferon-gamma using a G-quadruplex-selective iridium(iii) complexElectronic supplementary information (ESI) available. See DOI: 10.1039/c5cc06655g

In this study, we synthesized a series of 9 luminescent iridium( iii ) complexes and studied their ability to function as luminescent probes for G-quadruplex DNA. The iridium( iii ) complex 8 [Ir(pbtz) 2 (dtbpy)]PF 6 (where pbtz = 2-phenylbenzo[ d ]thiazole; dtbpy = 4,4′-di- tert -butyl-2,2′-bipyridine) showed high selectivity for G-quadruplex DNA over single-stranded and double-stranded DNA, and was subsequently utilized for the development of a label-free oligonucleotide-based assay for interferon-gamma (IFN-γ), an important biomarker for a range of immune and infectious diseases, in aqueous solution. We further demonstrated that this assay could monitor IFN-γ levels even in the presence of cellular debris. This assay represents the first G-quadruplex-based assay for IFN-γ detection described in the literature. A novel luminescent G-quadruplex-selective iridium( iii ) complex was employed in a G-quadruplex-based detection assay for IFN-γ.