title: DNA sensor with a dipyridophenazine complex of osmium(lI) as an electrochemical probe.
abstract: Application of a dipyrido[3,2-a:2',3'-c]phenazine (DPPZ)-type metal complex as an DNA electrochemical probe was studied. The introduction of electron-donating groups (NH2) was effective for controlling the redox potential and binding affinities of the DPPZ-type osmium complex. The [Os(DA-bpy)2DPPZ]2+ complex (DA-bpy; 4,4'-diamino-2,2'-bipyridine) had a lower half-wave potential (E 1/2) 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 other complexes. With a single-stranded DNA immobilized gold electrode, the hybridization signal (deltaI) of the [Os(DA-bpy)2DPPZ]2+ complex was linear in the concentration range of 1.0 pg mL(-1) - 0.12 microg 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.
authors.affiliation: Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima, Japan. maruyama@educ.cc.keio.ac.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Maruyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mishima
authors.forename: Keiji
authors.initials: K
authors.lastname: Minagawa
authors.forename: Junko
authors.initials: J
authors.lastname: Motonaka
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis*; D004277:DNA, Single-Stranded / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes / Q000592:standards; D015335:Molecular Probes / Q000592:standards; D009693:Nucleic Acid Hybridization; D017892:Osmium Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010619:Phenazines / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D004277:DNA, Single-Stranded; D015335:Molecular Probes; D017892:Osmium Compounds; D010619:Phenazines; C443808:dipyrido(3,2-a-2',3'-c)phenazine; D004247:DNA