Direct electron transfer of glucose oxidase at glassy carbon electrode modified with functionalized carbon nanotubes within a dihexadecylphosphate film |
| |
Authors: | Bruno C. JanegitzAuthor VitaeRasa PauliukaiteAuthor Vitae Mariana E. GhicaAuthor VitaeChristopher M.A. BrettAuthor Vitae Orlando Fatibello-FilhoAuthor Vitae |
| |
Affiliation: | a Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, São Carlos, SP, Brazil b Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal |
| |
Abstract: | 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. |
| |
Keywords: | Glucose oxidase Carbon nanotubes Dihexadecylphosphate (DHP) Direct electron transfer Glucose biosensor |
本文献已被 ScienceDirect 等数据库收录! |
|