Wiring laccase on covalently modified graphene: carbon nanotube assemblies for the direct bio-electrocatalytic reduction of oxygen.

Reduced graphene oxide (RGO) was covalently functionalized by the in situ generation and reduction of anthraquinone diazonium salt. Deposition on multi-wall carbon nanotube (MWCNT) electrodes prevents the aggregation of RGO nanosheets and allows the stable deposition of modified graphene, accompanied with excellent electron transfer properties. Laccases were immobilized on the nanostructured electrode by the interaction between the anthraquinone moiety and the laccase hydrophobic pocket located near the T1 copper center. The MWCNT/f-RGO electrode exhibits efficient bioelectrocatalytic oxygen reduction, with current densities of up to 0.9 mA cm(-2) .