Diazonium Electrografting vs. Physical Adsorption of Azure A at Carbon Nanotubes for Mediated Glucose Oxidation with FAD-GDH

Andrew J. Gross, Shunya Tanaka, Clara Colomies, Fabien Giroud, Yuta Nishina, Serge Cosnier, Seiya Tsujimura, Michael Holzinger

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

The electrochemical reduction of aryldiazonium salts is a versatile and direct route to obtain robust covalently modified electrodes. We report here a comparative study of Azure A modified carbon nanotube electrodes prepared by diazonium electrografting and by physical adsorption for bioelectrocatalytic glucose oxidation with fungal FAD-glucose dehydrogenase from Aspergillus sp. The electrografted and adsorbed electrodes exhibited different reversible electroactivity consistent with polymer-type and monomer-type phenothiazine surface assemblies, respectively. The electrografted Azure A electrodes exhibited superior mediated bioelectrocatalysis compared to the adsorbed Azure A electrodes. A more than 10-fold higher catalytic current up to 2 mA cm−2 at 0.2 V vs. Ag/AgCl together with a similarly low onset potential of −0.05 V vs. Ag/AgCl was observed at the electrografted electrodes. Faster estimated electron transfer kinetics and a +200 mV potential shift for the polymer-type redox couple vs. the adsorbed monomer-type couple underlines the favourable driving force for mediated electron transfer with the buried FAD active site for the diazonium-derived bioelectrode.

Original languageEnglish
Pages (from-to)4543-4549
Number of pages7
JournalChemElectroChem
Volume7
Issue number22
DOIs
Publication statusPublished - Nov 16 2020

Keywords

  • FAD dependant glucose dehydrogenase
  • bioelectrocatalysis
  • biofuel cell anode
  • enzymatic bioelectrode
  • phenothiazine redox mediator

ASJC Scopus subject areas

  • Catalysis
  • Electrochemistry

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