CONSTRUCTION OF SEC CTC ELECTRODES FOR DIRECT ELECTRON TRANSFERRING BIOSENSORS/

A stable organic charge-transfer-complex (CTC) electrode for the direc t oxidation of flavoproteins has been constructed and the mode of elec tron transfer is described. Tetrathiafulvalene-tetracyanoquinodimethan e (TTF-TCNQ) is grown at the surface of a shapable electroconductive ( SEC) film (a polyanion-doped polypyrrole film) in such a way that it m akes a tree-shaped crystal structure standing vertically on the surfac e. Glucose oxidase (GOD) is adsorbed and cross-linked under dry condit ions with glutaraldehyde to fix at the surface of the CTC structure. B ecause of the close proximity and the favorable orientation of the enz yme at the CTC surface, a direct electron transfer between the active center of the enzyme and the crystal electrode takes place, which lead s to a glucose sensor with remarkably improved performance. The kineti c parameters of the GOD/CTC/SEC electrode are reported. A mechanism of direct electron transfer is proposed.