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 w ere studied electrochemically. The binding constant of [Os(5,6-dmphen)(3)]( 2+), K = 4.2 x 10(5) M-1 was found to be larger than those observed for the known metal complex indicator and osmium complexes with methyl phenanthrol ine 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 se lectively detect DNA in a range of 6.9 x 10(-10) to 6.9 x 10(-5) g/ml. (C) 2001 Elsevier Science B.V. All rights reserved.