Enhanced Direct Electron Transfer of a Multihemic Nitrite Reductase on Single‐walled Carbon Nanotube Modified Electrodes |
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| Authors: | Célia M. Silveira Jessica Baur Michael Holzinger José J. G. Moura Serge Cosnier M. Gabriela Almeida |
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| Affiliation: | 1. REQUIMTE – Departamento de Química, CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829‐516 Caparica, Portugal;2. Département de Chimie Moléculaire, UMR‐5250, ICMG FR‐2607, CNRS, Université Joseph Fourier, Grenoble, France;3. Escola Superior de Saúde Egas Moniz, Monte de Caparica, 2829‐511 Caparica, Portugal telephone: +351?212948550;4. fax: +351?212948300 |
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| Abstract: | Single‐walled carbon nanotubes (SWCNTs) deposits on glassy carbon and pyrolytic graphite electrodes have dramatically enhanced the direct electron transfer of the multihemic nitrite reductase from Desulfovibrio desulfuricans ATCC 27774, enabling a 10‐fold increase in catalytic currents. At optimal conditions, the sensitivity to nitrite and the maximum current density were 2.4±0.1 A L mol?1 cm?2 and 1500 µA cm?2, respectively. Since the biosensor performance decreased over time, laponite clay and electropolymerized amphiphilic pyrrole were tested as protecting layers. Both coating materials increased substantially the bioelectrode stability, which kept about 90 % and 60 % of its initial sensitivity to nitrite after 20 and 248 days, respectively. |
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| Keywords: | Carbon nanotubes Nitrite reductase Direct electron transfer Polypyrrole Clay |
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