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DNA electrochemical sensor using osmium complex
K Maruyama1, Y Mishima, J Motonaka
1Department of Chemical Science and Technology, Faculty of Engineering, University of Tokushima, Minami-josanjima 2-1, Tokushima 770-8506, Japan.
Abstract:
The [Os(DA-bpy)2DPPZ]2+ complex (DPPZ; dipyrido [a:2',3'-c] phenazine, DA-bpy; 4,4'-diamino-2,2'-bipyridine) had a lower half-wave potential (E1/2) of 147 mV (vs. Ag|AgCl) and higher binding affinity with DNA (binding constant, K = 3.1 x 10(7) M-1) than those of DPPZ type metal complexes. With a single stranded DNA (ssDNA) immobilized gold electrode, the hybridization signal (delta I) of the [Os(DA-bpy)2DPPZ]2+ complex was linear in the concentration range of 1.0 pg ml-1-0.12 microgram ml-1 for the targeted DNA with a regression coefficient of 0.999. The detection limit was 0.1 pg ml-1. The 400 bp yAL3 gene was also detected with good sensitivity and selectivity using the [Os(DA-bpy)2DPPZ]2+ complex.