title: Development of a cyclometalated iridium complex with specific intramolecular hydrogen-bonding that acts as a fluorescent marker for the endoplasmic reticulum and causes photoinduced cell death.
abstract: Cyclometalated iridium complexes have important applications as phosphorescent probes for cellular imaging due to their photophysical properties. Moreover, these properties also make them potential candidates as photosensitizers for photodynamic therapy (PDT) of tumors and skin diseases. Treatment of MCF7 breast carcinoma cells with a heteroleptic phosphorescent cyclometalated iridium(III) complex C2 followed by confocal imaging indicates that the complex selectively localizes and exhibits high fluorescence in the endoplasmic reticulum. In an unprecedented approach, systematic alteration of functional groups or the metal core in C2 to synthesize a series of iridium(III) complexes (C1–C10) and an organometallic rhenium complex C11 with an imidazolyl modified phenanthroline ligand has indicated the functional groups and their interactions that are responsible for this selective localization. Remarkably, the exposure of the cells treated with C2 to irradiation at 405 nm for one hour led to membrane blebbing and cell death, demonstrating a photosensitizing property of the compound.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur Campus, Mohanpur, Nadia, West Bengal 741252, India. parna@iiserkol.ac.in.
authors.forename: Soumik
authors.initials: S
authors.lastname: Mandal
authors.forename: Dipak K
authors.initials: DK
authors.lastname: Poria
authors.forename: Ritabrata
authors.initials: R
authors.lastname: Ghosh
authors.forename: Partho Sarothi
authors.initials: PS
authors.lastname: Ray
authors.forename: Parna
authors.initials: P
authors.lastname: Gupta
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy; D002470:Cell Survival / Q000187:drug effects*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D003500:Cyclization; D004721:Endoplasmic Reticulum / Q000187:drug effects*; D005260:Female; D005453:Fluorescence; D006801:Humans; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry; D007495:Iridium / Q000737:chemistry* / Q000494:pharmacology*; D061986:MCF-7 Cells; D018613:Microscopy, Confocal; D010778:Photochemotherapy
chemical_list: D056831:Coordination Complexes; D007093:Imidazoles; D007495:Iridium; C029899:imidazole