Resulting Glucose Biosensor Research Articles

Amperometric Glucose Biosensor Based on Sol-Gel-Derived Zirconia/Nafion Composite Film as Encapsulation Matrix

An amperometric glucose biosensor has been developed based on the use of the nanoporous composite film of sol-gel-derived zirconia and perfluorosulfonated ionomer, Nafion, for the encapsulation of glucose oxidase (GOx) on a platinized glassy carbon electrode. Zirconium isopropoxide (ZrOPr) was used as a sol-gel precursor for the preparation of zirconia/Nafion composite film and the performance of the resulting glucose biosensor was tuned by controlling the water content in the acid-catalyzed hydrolysis of sol-gel stock solution. The presence of Nafion polymer in the sol-gel-derived zirconia in the biosensor resulted in faster response time and higher sensitivity compared to those obtained at the pure zirconia- and pure Nafion-based biosensors. Because of the nanoporous nature of the composite film, the glucose biosensor based on the zirconia/Nafion composite film can reach 95% of steady-state current less than 5 s. In addition, the biosensor responds to glucose linearly in the range of 0.03-15.08 mM with a sensitivity of 3.40 <TEX>$\mu$</TEX>A/mM and the detection limit of 0.037 mM (S/N = 3). Moreover, the biosensor exhibited good sensor-to-sensor reproducibility (~5%) and long-term stability (90% of its original activity retained after 4 weeks) when stored in 50 mM phosphate buffer at pH 7 at 4 <TEX>${^{\circ}C}$</TEX>.

60]Fullerene-mediated amperometric biosensors

In this report the use of [60]fullerene as a novel mediator in amperometric biosensors is presented. Different amounts of the fullerene were immobilized by adsorption into a porous carbon electrode prior the introduction of the enzyme (glucose oxidase). The effects of the amount of fullerene immobilized on the analytical characteristics of the resulting glucose biosensor are shown.

Enzymatically prepared poly(hydroquinone) as a mediator for amperometric glucose sensors

Poly(hydroquinone) (PHQ), synthesized from glucose-β- d-hydroquinone by peroxidase-catalyzed polymerization in aqueous solution and placed on glassy carbon electrodes, behaves as a redox mediator for glucose sensing. The highly selective nature of enzymatic catalysis leads to PHQ with a unique structure which is more soluble in organic solvents and more electrochemically active, as compared to that prepared via electrochemical methods. A glucose sensor is constructed in a pellet form with PHQ, glucose oxidase (GOD) and graphite powder. PHQ retains its redox activity and reversibility in the solid state and effectively mediates the electron transfer between the electrode and GOD. Resulting glucose biosensors possess sub-minute response times over a dynamic range from 1 to 30 mM. The PHQ mediator permits sensor operation at 100 mV (versus SCE), thereby reducing susceptibility toward common endogenous, easily oxidizable interferences.

Amperometric enzyme‐modified electrodes based on tetrathiafulvalene derivatives for the determination of glucose

AbstractA number of tetrathiafulvalene (TTF) derivatives have been synthesized and tested as electron transfer mediators in glucose oxidase‐based amperometric biosensors. Using cyclic voltammetry and stationary potential experiments, it is shown that several of these derivatives can effectively mediate electron transfer from the reduced flavin adenine dinucleotide redox centers of glucose oxidase to a conventional carbon paste electrode. An insoluble polymeric electron relay system, based on the covalent attachment of TTF moieties to a highly flexible siloxane polymer, is also shown to facilitate a flow of electrons from the enzyme to the electrode. The resulting glucose biosensors function efficiently over a clinically relevant range of glucose concentrations.