Detection of target DNA by electrochemical method

The interaction of the osmium complexes {[Os(bpy)3]3+ (bpy=bipyridine), [Os(phen)3]2+ (phen=1,10-phenanthroline), [Os(5,6-dmphen)3]2+ (5,6-dmphen=5,6-dimethyl-1,10-phenanthroline), and [Os(4,7-dmphen)3]2+ (4,7-dmphen=4,7-dimethyl-1,10-phenanthroline)} with calf thymus DNA were studied electrochemically. The binding constant of [Os(5,6-dmphen)3]2+, K=4.2×105 M−1 was found to be larger than those observed for the known metal complex indicator and osmium complexes with methyl phenanthroline ligands. This paper shows that a DNA sensor system with [Os(5,6-dmphen)3]2+ as a hybridization indicator and square wave voltammetry, could selectively detect DNA in a range of 6.9×10−10 to 6.9×10−5 g/ml.