Glucose Oxidase-Modified SnO2 Electrode as Electrochemical Glucose Sensor

Abstract

Glucose oxidase was chemically immobilized on an SnO2 electrode via 1) 2,4,6-trichloro-1,3,5-triazine, 2) 3-aminopropyltriethoxysilane and glutaraldehyde, or 3) crosslinkage of enzyme molecules by glutaraldehyde. These enzyme-immobilized electrodes were compared regarding the performance as amperometric glucose sensors.

Enzyme monolayer- and bilayer-modified tin oxide electrodes for the determination of hydrogen peroxide and glucose

“…Figure 5 depicts the performance of the bienzyme electrode as a glucose sensor. In comparison with the GOx monolayer-modified electrode described in a previous work (9), the present sensor exhibits about 10-fold higher sensitivity, 50-fold lower detection limit, and 6-fold faster response. This is in line with the acceleration of hydrogen peroxide redox processes, which are slow on a bare tin oxide electrode (Figure 2).…”

“…In most of our previous works (9)(10)(11) hydrogen peroxide generated by glucose oxidation was directly oxidized on a tin oxide electrode. The high overpotential for direct oxidation of hydrogen peroxide necessitated sensor operation at +800 to +900 mV vs Ag/AgCI, so that electroactive substances present as impurities in samples are liable to interfere with the assay.…”

“…Though a direct electron transfer is possible between an electrode and a peroxidase catalyzing the reduction of hydrogen peroxide (4)(5)(6)8), this is generally a slow process on common electrode materials. An appropriate electron donor can mediate the electron transfer between peroxidase and an electrode (3,7), and hence such a mediator is expected to improve the performance of a peroxidase-based hydrogen peroxide sensor. In recent papers we described fabrication of glucose sensors modified with a glucose oxidase (GOx) monolayer (9)(10)(11). Chemical immobilization of an enzyme as a monolayer gives 1 Present address: Department of Image Science and Engineering, Faculty of Engineering, Chiba University, Yayoi-cho, Chiba 260, Japan.…”

Bioanalytical Application of the Ordered Mesoporous Carbon Modified Electrodes

“…Briefly, 2.5 mg BSA and 0.5 mg enzyme (GOD or ADH) were dissolved in 50 mL phosphate buffer solution (PBS, 0.05 M, pH 7.4), and then 5 mL glutaraldehyde (5%) was added to get a homogenous mixture. Finally, 5 mL of the mixture was dropped onto the surface of the OMCE (or CNTE and GPE) with a microsyringe and allowed the enzyme film to dry and solidification in the shady and cool conditions [32]. The resulting bioelectrodes were abbreviated as OMC/ GOD, CNT/GOD, and GP/GOD for GOD based electrodes and OMC/ADH, CNT/ADH, and GP/ADH for ADH based ones.…”

Electrostatic Immobilization of Glucose Oxidase in a Weak Acid, Polyelectrolyte Hyperbranched Ultrathin Film on Gold: Fabrication, Characterization, and Enzymatic Activity

“…Several techniques have been used to immobilize biologically active molecules within or on polymer-based devices. These include retention by adsorption at solid interfaces, − cross-linking of the enzyme to a support or to other enzymes with bifunctional agents, − physical retention within polymeric matrixes, − and covalent − or ionic − binding to functionalized supports. − While these methods have been used successfully, significant difficulties may be encountered during implementation. For example, harsh synthetic conditions required for immobilization may lead to enzyme degradation, the enzyme immobilization matrix may lead to slow substrate mass transfer, and leaching of the enzyme results in sensor drift. − Another difficulty involves low capacity of the host for the enzyme.…”