A carbon nanotube layered electrode for the construction of the wired bilirubin oxidase oxygen cathode

Oxidatively treated carbon nanotubes were coated on a glassy carbon surface to form a CNT-layer. On the CNT-layered GC surface, a redox hydrogel film of the copolymer, of polyacryamide and poly(N-vinylimidazole) complexed with [Os(4,4'-dichloro-2,2'-bipyridine)₂Cl]^+/2+ wiring bilirubin oxidase was immobilized. A good contact was achieved between the hydrogel film and the hydrophilic CNT-layer with carboxylated CNTs. The prepared bilirubin oxidase cathode on the CNT-layer was employed for the electrocatalytic reduction of O₂, and enhanced current and stability were observed. Electron transfers from the electrode surface O₂ molecules were analyzed. The optimal composition of the enzyme, redox polymer, and cross-linker in the catalyst and the thickness of the CNT-layer were determined.