title: Echinomycin and cobalt-phenanthroline as redox indicators of DNA hybridization at gold electrodes.
abstract: A bis-intercalator echinomycin (ECHI) and a simple intercalator [Co(phen)3]3+ were used as a novel electrochemical redox indicators to detect DNA hybridization at gold electrodes (AuE). In order to minimize the nonspecific adsorption of oligonucleotides (ODN), the thiol-derivatized oligonucleotides were immobilized onto AuE in the first step, and the exposition of AuE to 6-mercapto-1-hexanol (MCH) followed in the second step of this procedure. In this arrangement good reproducibility and discrimination between single-stranded (ss) probe and double-stranded (ds) hybrid DNA were obtained. While both redox indicators showed a good ability to discriminate between the ss probe and ds hybrid DNA, the signals of ECHI were by an order of maginitude higher than those of [Co(phen)3]3+ in a good agreement with stronger DNA binding by the bis-intercalator as compared to the simple intercalator. In addition, DNA single-base mismatch (DNA point mutation) was easily detected by means of ECHI.
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Ege University, 35100 Bornova, Izmir, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Karadeniz
authors.forename: Beste
authors.initials: B
authors.lastname: Gulmez
authors.forename: Arzum
authors.initials: A
authors.lastname: Erdem
authors.forename: Frantisek
authors.initials: F
authors.lastname: Jelen
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozsoz
authors.forename: Emil
authors.initials: E
authors.lastname: Palecek
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015374:Biosensing Techniques; D003035:Cobalt / Q000737:chemistry / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D004448:Echinomycin / Q000378:metabolism*; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D006538:Heptanoic Acids / Q000737:chemistry; D007202:Indicators and Reagents / Q000494:pharmacology; D007364:Intercalating Agents / Q000494:pharmacology; D008957:Models, Genetic; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000737:chemistry; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry; D017354:Point Mutation; D013438:Sulfhydryl Compounds; D013871:Thiones / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004277:DNA, Single-Stranded; D006538:Heptanoic Acids; D007202:Indicators and Reagents; D007364:Intercalating Agents; D009841:Oligonucleotides; D010618:Phenanthrolines; D013438:Sulfhydryl Compounds; D013871:Thiones; D003035:Cobalt; D004448:Echinomycin; C062867:7-mercaptoheptanoic acid; D006046:Gold; D004247:DNA