Bifunctional trehalose anode incorporating two covalently linked enzymes acting in series.

A bienzymatic electrode incorporating trehalase (Tre) and glucose oxidase (GOx) covalently bound to the surface of Pt through a functionalized thiol linker (Tre|GOx|Pt) has been designed and assembled and its catalytic properties examined by chemical and electrochemical methods in aqueous phosphate buffer solutions (PBS, pH 7.4). Exposure of Tre|GOx|Pt to PBS containing trehalose (Tr) and subsequent polarization at 0.6 V versus Ag/AgCl yielded after a few minutes well-defined steady-state currents ascribed to the oxidation of hydrogen peroxide generated by the GOx-mediated oxidation of glucose (Gl) produced by the Tre-mediated dissociation of Tr. Plots of the steady-state currents versus [Tr] over the range examined, i.e., 5-25 mM, were found to be linear. Implications of these results toward the development of an implantable biofuel cell as an autonomous energy conversion device for insects are discussed.