Application of Tetrathiafulvalene-Modified Carbon Nanotubes to Preparation of Integrated Mediating System for Bioelectrocatalytic Oxidation of Glucose

Multiwalled carbon nanotubes (CNTs), that are modified with ultrathin layers of tetrathiafulvalene (TTF), were demonstrated to form a stable colloidal suspension. Such dispersion was exploited to fabricate an integrated mediating system (utilizing both highly conductive carbon nanostructures, CNTs, and a redox mediator, TTF) capable of facilitating electron transfers between the active sites of the enzyme (glucose oxidase) and the electrode surface. The resulting bioelectrocatalytic system produced sizeable glucose oxidation currents in phosphate buffer solution (pH 7.0). For comparison, the system utilizing TTF-free (bare) CNTs and the glucose oxidase enzyme showed relatively much lower activity towards the glucose oxidation. Formation, electrocatalytic reactivity. durability, and morphology of proposed bioelectrocatalytic systems were examined using cyclic voltammetry, potential step techniques, rotating disk voltammetry and transmission electron microscopy. The whole concept of the preparation of CNT-supported redox mediating systems is of potential utility to bioelectroanalytical chemistry.