Nanostructured electrodes based on multiwalled carbon nanotube/glyconanoparticles for the specific immobilization of bilirubin oxidase: Application to the electrocatalytic O₂ reduction

Here we describe the design and the characterization of novel electrode materials consisting of multi-walled carbon nanotubes coated with glyconanoparticles (GNPs) functionalized with anthraquinone sulfonate. The resulting modified electrodes were characterized by scanning electron microscopy and cyclic voltammetry. Their electrochemical behavior reveals a stable pH-dependent redox signal characteristic of anthraquinone sulfonate. Immobilization of bilirubin oxidase on these three-dimensional electrodes leads to the electroenzymatic reduc-tion of O2 to water with an onset potential of 0.5 V/SCE (saturated calomel electrode). A catalytic cathodic current of 174 mu A (0.88 mA cm-2) at 0.1 V/SCE, demonstrates that glyconanoparticles modified by anthraqui-none sulfonate were able to interact and orientate bilirubin oxidase by electrostatic interactions.