title: Photoelectrochemical oxidation of DNA by ruthenium tris(bipyridine) on a tin oxide nanoparticle electrode.
abstract: Selective photoelectrochemical oxidation of DNA was achieved by ruthenium tris(bipyridine) immobilized on a tin oxide nanoparticle electrode. The metal complex was covalently attached to a protein, avidin, which adsorbed strongly on the tin oxide electrode by electrostatic interaction. Upon irradiation with 473-nm light, anodic photocurrent was generated in a blank electrolyte and was enhanced significantly after addition of poly(guanadylic acid) (poly-G) into the electrolyte. The current increased progressively with the nucleotide concentration, suggesting the enhancement effect was related to poly-G. The action spectrum indicates that the photocurrent was initiated by light absorption of the ruthenium compound immobilized on the electrode. Among the various polynucleotides examined, poly-G produced the largest photocurrent increase, followed by poly-A, single-stranded DNA, chemically damaged DNA, and double-stranded DNA, whereas poly-C and poly-U showed little effect. The combined experimental data support the hypothesis that the photoexcited Ru2+ species injects an electron into the semiconductor and produces Ru3+, which is then reduced back to Ru2+ by guanine and adenine bases in DNA, resulting in the recycling of the metal complex and enhanced photocurrent. The photoelectrochemical reaction can be employed as a new method for the detection of DNA damage.
authors.forename: Minmin
authors.initials: M
authors.lastname: Liang
authors.forename: Shili
authors.initials: S
authors.lastname: Liu
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Wei
authors.forename: Liang-Hong
authors.initials: LH
authors.lastname: Guo
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D004566:Electrodes; D053758:Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D004247:DNA