Graphitized-Carbon-Nanofiber Paper-Enzyme Electrode Fabrication Through Non-Covalent Modification for Enzyme Biofuel Cell Application

Abstract

Carbon nanofibers are an emerging smart material that are promising for use as a biosensor and a biofuel cell transducer material due to their morphological and electrochemical characteristics. In particular, graphitized carbon nanofibers possess unique structures of graphite-like edges within their high surface area that provide a large active site for enzyme attachment. For a specific application such as a biofuel cell, which requires highly stable electrical communication and electricity generation, non-covalent enzyme immobilization using bifunctional molecule is suggested as an appropriate approach because it does not change the carbon hybridization from sp(2) to sp(3) as covalent immobilization by acid treatment does. Graphitized carbon-nanofiber paper (GCNFp) electrode were fabricated through dispersion-filtration method in which glucose oxidase as model enzyme were immobilized by a bifunctional molecule that forms pi-pi stacking of the pyrene moiety with the nanofiber wall coupled by a reactive end-amine reaction. This system provides a practical enzyme-electrode hybrid that facilitates comparatively faster enzyme-electrode electrical communication than other system using similar material, as calculated from the heterogeneous electron-transfer rate constant (K-s) which was 5.45 s(-1).