title: Luminescent biological probes derived from ruthenium(II) estradiol polypyridine complexes.
abstract: Four luminescent ruthenium(II) polypyridine estradiol complexes [Ru(NwedgeN)2(bpy-estradiol)](PF6)2 (NwedgeN = 2,2'-bipyridine (bpy), 4,7-diphenyl-1,10-phenanthroline (Ph2-phen); bpy-estradiol = 5-(4-(17alpha-ethynylestradiolyl)phenyl)-2,2'-bipyridine (bpy-ph-est), 4-(N-(6-(4-(17alpha-ethynylestradiolyl)benzoylamino)hexyl)aminomethyl)-4'-methyl-2,2'-bipyridine (mbpy-C6-est)) have been designed as new luminescent biological probes. The lipophilicity and photophysical and electrochemical properties of these complexes have been investigated. Upon photoexcitation, all the complexes exhibited intense and long-lived triplet metal-to-ligand charge-transfer (3MLCT) (dpi(Ru) --> pi*(diimine)) emission in fluid solutions at 298 K and in low-temperature glass. The binding of the complexes to estrogen receptor-alpha (ERalpha) has been studied by emission titrations. The Ph2-phen complexes showed emission enhancement and increased lifetimes upon binding to the protein. Additionally, the cytotoxicity of the complexes toward the HeLa cell line has been examined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay and the IC50 values ranged from 83.1 to 166.6 microM (cisplatin showed an IC50 value of 34.3 microM under the same experimental conditions). Furthermore, the cellular uptake of the complexes has been investigated by flow cytometry and laser-scanning confocal microscopy.
authors: Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, PR China. bhkenlo@cityu.edu.hk
authors: Kenneth Kam-Wing
authors: KK
authors: Lo
authors: Terence Kwok-Ming
authors: TK
authors: Lee
authors: Jason Shing-Yip
authors: JS
authors: Lau
authors: Wing-Lin
authors: WL
authors: Poon
authors: Shuk-Han
authors: SH
authors: Cheng
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D004563:Electrochemistry; D004958:Estradiol / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods; D015335:Molecular Probes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D011108:Polymers / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D018675:Toxicity Tests
chemical_list: D015335:Molecular Probes; D009942:Organometallic Compounds; D011108:Polymers; D011725:Pyridines; D004958:Estradiol; D012428:Ruthenium