Glucose Oxidase Catalyzed Self-Assembly of Bioelectroactive Gold Nanostructures

Abstract

Glucose oxidase catalyzes the formation of metallic gold particles in immediate proximity of the protein from gold (III) chloride in the absence of any other catalytic or reductive substrates. The protein-mediated gold reduction reaction leads to size-controllable gold particle formation and concomitant association of the enzyme in an electrically conductive metallic template. Such an enzyme immobilization strategy provides a simple and rapid method to create an intimate interface between glucose oxidase and a conductive matrix, which can be joined to an electrode surface. Model electrodes were prepared by entraining the glucose oxidase/gold particles onto carbon paper. Voltammetry of the resulting electrodes revealed stable oxidation and reduction peaks at a potential close to that of the standard value for the FAD/FADH₂ cofactor of immobilized glucose oxidase. The gold electrodes exhibit catalytic activity in the presence of glucose confirming the entrapment of active glucose oxidase within the gold architecture. The resulting composite material can be successfully integrated with electrodes of various designs for biosensor and biofuel cell applications.