title: Single-walled carbon nanotubes covalently functionalized with polytyrosine: A new material for the development of NADH-based biosensors.
abstract: We report for the first time the use of single-walled carbon nanotubes (SWCNT) covalently functionalized with polytyrosine (Polytyr) (SWCNT-Polytyr) as a new electrode material for the development of nicotinamide adenine dinucleotide (NADH)-based biosensors. The oxidation of glassy carbon electrodes (GCE) modified with SWCNT-Polytyr at potentials high enough to oxidize the tyrosine residues have allowed the electrooxidation of NADH at low potentials due to the catalytic activity of the quinones generated from the primary oxidation of tyrosine without any additional redox mediator. The amperometric detection of NADH at 0.200V showed a sensitivity of (217±3)µAmM(-1)cm(-2) and a detection limit of 7.9nM. The excellent electrocatalytic activity of SWCNT-Polytyr towards NADH oxidation has also made possible the development of a sensitive ethanol biosensor through the immobilization of alcohol dehydrogenase (ADH) via Nafion entrapment, with excellent analytical characteristics (sensitivity of (5.8±0.1)µAmM(-1)cm(-2), detection limit of 0.67µM) and very successful application for the quantification of ethanol in different commercial beverages.
authors.affiliation: INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Marcos
authors.initials: M
authors.lastname: Eguílaz
authors.affiliation: INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Gutierrez
authors.affiliation: Grupo de nanoestructuras de carbono y Nanotecnología, Departamento de Nanotecnología, Instituto de Carboquímica (CSIC), 50018 Zaragoza, Spain.
authors.forename: Jose Miguel
authors.initials: JM
authors.lastname: González-Domínguez
authors.affiliation: Grupo de nanoestructuras de carbono y Nanotecnología, Departamento de Nanotecnología, Instituto de Carboquímica (CSIC), 50018 Zaragoza, Spain. Electronic address: mtmartinez@icb.csic.es.
authors.forename: María T
authors.initials: MT
authors.lastname: Martínez
authors.affiliation: INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, 5000 Córdoba, Argentina. Electronic address: grivas@fcq.unc.edu.ar.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Rivas
mesh_terms: D000426:Alcohol Dehydrogenase / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D000431:Ethanol / Q000032:analysis*; D009243:NAD / Q000032:analysis* / Q000737:chemistry; D058726:Nanoconjugates / Q000737:chemistry / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004800:Enzymes, Immobilized; D058726:Nanoconjugates; D037742:Nanotubes, Carbon; D010455:Peptides; D009243:NAD; C017663:polytyrosine; D000431:Ethanol; D000426:Alcohol Dehydrogenase
keywords: Alcohol dehydrogenase; Covalently functionalized carbon nanotubes; Electrochemical NADH sensor; Electrochemical ethanol biosensor; NADH electrocatalytic oxidation; Polytyrosine