Electrochemiluminescent Array to Detect Oxidative Damage in ds-DNA Using [Os(bpy) 2 (phen-benz-COOH)] 2+ /Nafion/Graphene Films

• Published in: ACS sensors Vol. 1; no. 3; p. 272
• Main Authors: Bist, Itti, Song, Boya, Mosa, Islam M, Keyes, Tia E, Martin, Aaron, Forster, Robert J, Rusling, James F
• Format: Journal Article
• Language: English
• Published: United States 01.01.2016
• Subjects: [Os(bpy)2(phen-benz-COOH)]2; electrochemiluminescence; DNA oxidation sensor; microwell array; oxidative stress
• ISSN: 2379-3694; 2379-3694
• DOI: 10.1021/acssensors.5b00189

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) (phen-benz-COOH)] (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, Cu , 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 Cu , NADPH, and model metabolites.