A plate−gap model of a porous enzyme doped electrode covered by a porous inert membrane has been proposed and analyzed. The two−dimensional−in−space mathematical model of the plate−gap biosensors is based on the reaction−diffusion equations containing a nonlinear term related to the Michaelis−Menten kinetics. Using numerical simulation of the biosensor action, the influence of the geometry of t...

A high-performance amperometric fructosyl valine (FV) biosensor was developed, based on immobilization of fructosyl amino-acid oxidase (FAO) on core-shell magnetic bionanoparticles modified gold electrode. Chitosan was used to introduce amino groups onto the surface of core-shell magnetic bionanoparticles (MNPs). With FAO as an enzyme model, a new fructosyl valine biosensor was fabricated. The ...

A potentiometric enzyme biosensor is a convenient detector for quantification of urea concentrations in industrial processes, or for monitoring patients with diabetes, kidney damage or liver malfunction. In this work, poly(3-hexylthiophene-co-3-thiopheneacetic acid) (P(3HT-co-3TAA)) was chemically synthesized, characterized and spin-coated onto conductive indium tin oxide (ITO) glass electrodes...

DFPase can hydrolyze the P-F bond of diisopropyl phosphate fluoride (DFP) to produce diisopropyl phosphate and HF. In this article, the activity of two kinds of DFPase from porcine liver was assayed by the methods of titration and F- ion sensitive electrode. The results showed that the activity of large molecular DFPase can be determined by both methods, but the activity of small molecular DFPa...

Amperometric biosensors consisting of oxidase and peroxidase have attracted great attention because of their wide application. The current work demonstrates a novel approach to construct an enzymatic biosensor based on TiO2 nanotube arrays (TiNTs) as a supporting electrode on which Prussian Blue (PB)-an "artificial enzyme peroxidase" and enzyme glucose oxidase (GOx) have been immobilized. For t...

Combinatorial methods were used to search for active alloy electrocatalysts for use in enzyme-free amperometric glucose sensors. Electrode arrays (715-member) containing combinations of Pt, Pb, Au, Pd, and Rh were prepared and screened by converting anodic current to visible fluorescence. The most active compositions contained both Pt and Pb. Bulk quantities of catalysts with compositions corre...

In the context of current Interest In ekctroanalytlcal sensors for blomedlcal appllcationr, enzyme klnetk parameters obtalned amperwtrkally were compared wlth those determlnd 8pectrophotometrIcaNy for ethanol oxklatlon catalyzed by alcohol dehydrogenase. The amperwtry was conducted at a platlnum rotated dkk electrode, utlllzlng hexacyanoferrah( I I I/I I ) as an electron shuttle between the enz...

The combination of enzymes with semiconductors enables the photoelectrochemical characterization of electron-transfer processes at highly active and well-defined catalytic sites on a light-harvesting electrode surface. Herein, we report the integration of a hydrogenase on a TiO2-coated p-Si photocathode for the photo-reduction of protons to H2. The immobilized hydrogenase exhibits activity on S...

A biosensor for measuring the antidiabetic potential of medicinal plants was developed by covalent immobilization of α-glucosidase (AG) enzyme onto amine-functionalized multi-walled carbon nanotubes (MWCNTs-NH2). The immobilized enzyme was entrapped in freeze-thawed polyvinyl alcohol (PVA) together with p-nitrophenyl-α-D-glucopyranoside (PNPG) on the screen-printed carbon electrode at low pH to...

The determination of mercury(II) ions at the trace level by inhibition of the invertase enzyme-catalysed hydrolysis of sucrose into glucose and fructose coupled to electrochemical batch injection analysis was investigated using two approaches. In the first, the glucose produced was detected by injection of 100 microliters samples into the batch injection cell containing a platinum electrode mod...