Direct electron transfer of glucose oxidase at glassy carbon electrode modified with functionalized carbon nanotubes within a dihexadecylphosphate film

Autor(es)

Janegitz, Bruno C. ^[1] ; Pauliukaite, Rasa ^[2] ; Ghica, Mariana E. ^[2] ; Brett, Christopher M. A. ^[2] ; Fatibello-Filho, Orlando ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Quim, Ctr Ciencias Exatas & Tecnol, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Coimbra, Dept Quim, Fac Ciencias & Tecnol, P-3004535 Coimbra - Portugal

• Tipo de documento: Artigo Científico
• Fonte: SENSORS AND ACTUATORS B-CHEMICAL; v. 158, n. 1, p. 411-417, NOV 15 2011.
• Citações Web of Science: 73

Resumo

A glassy carbon electrode modified with functionalized multiwalled carbon nanotubes (CNTs) immobilized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) in a dihexadecylphosphate film was prepared and characterized by cyclic voltammetry and scanning electron microscopy. It was used as a support for FAD or glucose oxidase (GOx) immobilization with EDC/NHS crosslinking agents. Cyclic voltammetry of GOx immobilized onto the surface of CNTs showed a pair of well-defined redox peaks, which correspond to the direct electron transfer of GOx, with a formal potential of -0.418 V vs. Ag/AgCl (3 M KCl) in 0.1 M phosphate buffer solution (pH 7.0). An apparent heterogeneous electron transfer rate constant of 1.69 s(-1) was obtained. The dependence of half wave potential on pH indicated that the direct electron transfer reaction of GOx involves a two-electron, two-proton transfer. The determination of glucose was carried out by square wave voltammetry and the developed biosensor showed good reproducibility and stability. The proposed method could be easily extended to immobilize and evaluate the direct electron transfer of other redox enzymes or proteins. (C) 2011 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 08/09893-0 - Desenvolvimento de biossensores utilizando nanotubos de carbono e nanopartículas
• Beneficiário: Bruno Campos Janegitz
• Modalidade de apoio: Bolsas no Brasil - Doutorado