Single-walled carbon nanotubes covalently functionalized with polytyrosine: A new material for the development of NADH-based biosensors

• Published in: Biosensors & bioelectronics Vol. 86; pp. 308 - 314
• Main Authors: Eguílaz, Marcos, Gutierrez, Fabiana, González-Domínguez, Jose Miguel, Martínez, María T., Rivas, Gustavo
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.12.2016
• Subjects: Alcohol dehydrogenase; Alcohol Dehydrogenase - chemistry; Biosensors; Conductometry - instrumentation; Covalence; Covalently functionalized carbon nanotubes; Electrochemical ethanol biosensor; Electrochemical NADH sensor; Enzymes, Immobilized - chemistry; Equipment Design; Equipment Failure Analysis; Ethanol; Ethanol - analysis; Ethyl alcohol; NAD - analysis; NAD - chemistry; NADH; NADH electrocatalytic oxidation; Nanoconjugates - chemistry; Nanoconjugates - ultrastructure; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Oxidation; Oxidation-Reduction; Peptides - chemistry; Polytyrosine; Reproducibility of Results; Sensitivity and Specificity; Single wall carbon nanotubes; Tyrosine; Electrochemical ethanol biosensor; Covalently functionalized carbon nanotubes; NADH electrocatalytic oxidation; Electrochemical NADH sensor; Alcohol dehydrogenase; Polytyrosine
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2016.06.003

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−1cm−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−1cm−2, detection limit of 0.67µM) and very successful application for the quantification of ethanol in different commercial beverages. [Display omitted] •The oxidation of SWCNT-Polytyr generates surface quinone groups that facilitates the oxidation of NADH.•NADH is catalytically oxidized at GCE/SWCNT-Polytyr(oxidized).•GCE/SWCNT-Polytyr(oxidized) is a robust platform for further immobilization of ADH.•GCE/SWCNT-Polytyr(oxidized)//ADH/Naf allows the quantification of ethanol in alcoholic beverages.