title: Reusable impedimetric aptasensor.
abstract: A novel impedimetric aptasensor using a mixed self-assembled monolayer composed of thiol-modified thrombin binding aptamer and 2-mercaptoethanol on a gold electrode is reported. The changes of interfacial features of the electrode were probed in the presence of the reversible redox couple, Fe(CN)6(3-/4-), using impedance measurements. The electrode surface was partially blocked due to the self-assembly of aptamer or the formation of the aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by electrochemical impedance spectroscopy or cyclic voltammetry. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution, and the immobilized aptamer subsequently was used for repeated detection of thrombin. The aptamer-functionalized electrode showed a linear response of the charge-transfer resistance to the increase of thrombin concentration in the range of 5.0-35.0 nM and the thrombin was easily detectable to a concentration of 2.0 nM.
authors.affiliation: Department of Chemistry, Faculty of Science, Mansoura University, 34517 Dumyat, Egypt. abd.radi@urv.net
authors.forename: Abd-Elgawad
authors.initials: AE
authors.lastname: Radi
authors.forename: Josep Lluís
authors.initials: JL
authors.lastname: Acero Sánchez
authors.forename: Eva
authors.initials: E
authors.lastname: Baldrich
authors.forename: Ciara K
authors.initials: CK
authors.lastname: O'Sullivan
mesh_terms: D052157:Aptamers, Nucleotide / Q000235:genetics*; D015374:Biosensing Techniques / Q000379:methods*; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes
chemical_list: D052157:Aptamers, Nucleotide