title: Electrochemiluminescent Array to Detect Oxidative Damage in ds-DNA Using [Os(bpy)2(phen-benz-COOH)]2+/Nafion/Graphene Films.
abstract: Reactive oxygen species (ROS) oxidize guanosines in DNA to form 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG), a biomarker for oxidative stress. Herein we describe a novel 64-microwell electrochemiluminescent (ECL) array enabling sensitive multiplexed detection of 8-oxodG in ds-DNA without hydrolysis. Films of Nafion and reduced graphene oxide containing ECL dye [Os(bpy)2(phen-benz-COOH)]2+(OsNG, {bpy= 2,2'-bipyridine and phen-benz-COOH = (4-(1,10-phenanthrolin-6-yl) benzoic acid)}) were assembled into microwells on a pyrolytic graphite wafer to detect 8-oxodG in oligonucleotides by electrochemiluminescence (ECL). DNA oxidation by Fenton's reagent or by ROS formation during redox cycles involving NADPH, CuII, and model metabolites was monitored. UPLC-MS/MS of oxidized DNA samples were used for calibration. Detection limit for the fluidic arrays was one 8-oxodG per 670 intact nucleobases, or 0.15%. The method is sensitive enough to evaluate DNA oxidation from biologically relevant ROS-generating reactions of CuII, NADPH, and model metabolites.
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States.
authors.forename: Itti
authors.initials: I
authors.lastname: Bist
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States.
authors.forename: Boya
authors.initials: B
authors.lastname: Song
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States; Department of Chemistry, Tanta University, Tanta 31527, Egypt.
authors.forename: Islam M
authors.initials: IM
authors.lastname: Mosa
authors.affiliation: School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Tia E
authors.initials: TE
authors.lastname: Keyes
authors.affiliation: School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Aaron
authors.initials: A
authors.lastname: Martin
authors.affiliation: School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Forster
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States; Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States; School of Chemistry, National University of Ireland, Galway, Ireland; University of Connecticut Health Center, Farmington, Connecticut 06032, United States.
authors.forename: James F
authors.initials: JF
authors.lastname: Rusling
keywords: DNA oxidation sensor; [Os(bpy)2(phen-benz-COOH)]2+; electrochemiluminescence; microwell array; oxidative stress