title: Electrochemical DNA biosensor for the study of ciprofloxacin-DNA interaction.
abstract: The interaction of ciprofloxacin with DNA was studied by using an electrochemical DNA biosensor. The binding mechanism of ciprofloxacin was elucidated by using constant current potentiometry and differential pulse voltammetry at DNA-modified glassy carbon electrode. The decrease in the guanine oxidation peak area or peak current at +0.9 V was used as an indicator for the interaction mechanism in 0.2M acetate buffer (pH 5). The binding constant (K) values obtained were 1.33+/-0.02 x 10(4) and 1.32+/-0.08 x 10(4) M(-1) with constant current potentiometry and differential pulse voltammetry, respectively. A linear dependence of the guanine peak area or peak currents was observed in the range of 40-80 microM ciprofloxacin, with a detection limit of 24 microM with r=0.995 and 9 microM with r=0.999 by using constant current potentiometry and differential pulse voltammetry, respectively. Moreover, the influence of sodium and calcium ions was also studied to elucidate the mechanism of ciprofloxacin-DNA interaction at different solution conditions, and this proved to be helpful in understanding the ciprofloxacin-DNA interaction.
authors.affiliation: Bioprocess Technology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, Pakistan.
authors.forename: Haq
authors.initials: H
authors.lastname: Nawaz
authors.forename: Sakandar
authors.initials: S
authors.lastname: Rauf
authors.forename: Kalsoom
authors.initials: K
authors.lastname: Akhtar
authors.forename: Ahmad M
authors.initials: AM
authors.lastname: Khalid
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D015374:Biosensing Techniques / Q000379:methods*; D002118:Calcium / Q000737:chemistry / Q000494:pharmacology; D002939:Ciprofloxacin / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004563:Electrochemistry / Q000379:methods*; D006147:Guanine / Q000737:chemistry / Q000378:metabolism; D011199:Potentiometry; D012964:Sodium / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D006147:Guanine; D004247:DNA; D012964:Sodium; D002118:Calcium