Mesoporous TiO₂ films: New catalytic electrode fabricating amperometric biosensors based on oxidases

Abstract

A novel catalytic material (mesoporous TiOz films) for the cathodic detection of hydrogen peroxide in air-saturated aqueous solution is described. The immobilization of glucose oxidase (GOD) as enzyme model onto the TiOz electrode provides an efficient biosensor for the arnperometric detection of glucose at -0.15 V (vs. SCE). GOD molecules were immobilized in an inorganic laponite gel and cross-linked by glutaraldehyde. The highest sensitivity and detection limit were 3.33 mA M-' cm-' and 15 pM, respectively. In addition different procedures of enzyme immobilization including cross-linking with glutaraldehyde and physical entrapment in a functionalized polypyrrole film have been compared.

Nanochromics: old materials, new structures and architectures for high performance devices

“…The relevant properties of nanocrystalline films for electrochromic applications are their transparency to visible light, electronic conductivity, large surface area and affinity towards specific ligands. The derivatization of nanocrystalline films with different types of molecular monolayers led to, in addition to solar cells and electrochromic devices, to elaborate sensors, 20 photoelectrocatalytic, 21 electroluminescent 22 and photoelectrochromic devices. 23 The common principle of efficiency in these devices lies on fast interfacial electron transfer between the nanocrystalline material and the adsorbed modifier as well as on the high surface area of the substrate that amplifies optical phenomena by two or three orders of magnitude.…”

Mesoporous Transition Metal Oxide Ceramics

“…Depending on the concentration of mercaptopropylsilane, the Santa Barbara group found that they could systematically vary the surface coverage of these functional molecules from 10 % to 100 % density depending on the application. One of the first groups to functionalize organic monolayers onto transition metal oxide surfaces was that of Cosnier et al who immobilized glucose oxidase (GOD) proteins onto mesoporous TiO 2 films for the amperometric detection of glucose and found that successful chemical cross-linking between the surface and monolayer occurred using stationary potential patterns [81]. It was not until many years later that the functionalization of transition metal oxides had been further contemplated, with Mutin and co-workers the first to anchor organophosphorous acids (phosphoric, phosphonic, and phosphinic) onto microporous TiO 2 and ZrO 2 using sol-gel processing and surface modification [82].…”

Analytical Applications of Silica-Modified Electrodes -A Comprehensive Review

“…The interpretation of the voltammetric response is still not clear but the signals are consistent with a redox process involving Co(II) and Co(III) species. Finally, a recent work describes the interest of mesoporous TiO 2 films for the immobilization of GOD, and after coating the film onto a TiO 2 electrode the resulting system was applied as an amperometric biosensor for glucose with high sensitivity and a detection limit of 12 mM [301]. All these preliminary works demonstrate the attractive features arising from the intersection between this new family of materials and electrochemistry, which is thought to lead to major developments in the near future in the elaboration of new sensors.…”