title: Immobilization of DNA on glassy carbon electrodes for the development of affinity biosensors.
abstract: The adsorption and electrooxidation of nucleic acids on glassy carbon electrodes are evaluated by using chronopotentiometric stripping analysis. The influence of electrochemical pretreatments, supporting electrolyte, halides and monovalent cations levels as well as the role of the oligonucleotide length and composition, accumulation potential and time on the adsorption and further electrooxidation of oligo(dG)(11) and oligo(dG)(21) are discussed. The adsorption behavior of single and double stranded calf thymus DNA on untreated glassy carbon electrodes is also evaluated. Trace (microg/l) levels of the oligonucleotides and polynucleotides can be readily detected following short accumulation periods with detection limits of 25, 60, 126 and 219 microg/l for oligo(dG)(21), oligo(dG)(11), ss and ds calf thymus DNA, respectively. The confined DNA layers demonstrated to be stable in air, in 0.200 M acetate buffer pH 5.00 and in 0.020 M phosphate buffer pH 7.40+0.50 M NaCl.
authors.affiliation: INFIQC, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: M L
authors.initials: ML
authors.lastname: Pedano
authors.forename: G A
authors.initials: GA
authors.lastname: Rivas
mesh_terms: D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon; D002417:Cattle; D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D015342:DNA Probes / Q000138:chemical synthesis; D004277:DNA, Single-Stranded; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D009693:Nucleic Acid Hybridization / Q000379:methods; D009841:Oligonucleotides; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015342:DNA Probes; D004277:DNA, Single-Stranded; D009841:Oligonucleotides; D002244:Carbon; D004247:DNA; C427203:calf thymus DNA