Enzymatic bioelectrocatalysis is being increasingly exploited to better understand oxidoreductase enzymes, to develop minimalistic yet specific biosensor platforms, and to develop alternative energy conversion devices and bioelectrosynthetic devices for the production of energy and/or important chemical commodities. In some cases, these enzymes are able to electronically communicate with an app...

We have studied the direct electrochemistry of horseradish peroxidase (HRP) coupled to gold nanoparticles (AuNP) using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i) glutathione and (ii) lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP...

An enzyme electrode system for the determination of creatinine and creatine was developed by utilizing three enzymes: creatinine amidohydrolase (CA), creatine amidinohydrolase (Cl), and sarcosine oxidase (SO). These enzymes were co-immobilized onto the porous side of a cellulose acetate membrane with asymmetric structure, which has selective permeability to hydrogen peroxide. Two kinds of multi...

Amperometric enzyme electrode probes have been constructed for the specific determination of L-lysine and used in batch and flow analysis. The enzyme lysine oxidase was immobilized on a preactivated polymer support which was placed on a platinum electrode. Additional blocking membranes conferred high stability, reproducibility and avoided electrochemical and enzyme interferences. Parameters inc...

For more than three decades, the field of bioelectrochemistry has provided novel insights into the catalytic mechanisms of enzymes, the principles that govern biological electron transfer, and has elucidated the basic principles for bioelectrocatalytic systems. Progress in biochemistry, bionanotechnology, and our ever increasing ability to control the chemistry and structure of electrode surfac...

This research was to prepare the titanium dioxide nanotube arrays (TiNT arrays) and deposit the Au nanoparticles on its surface using the pulse electrodeposition technique. The Au nanoparticles-TiNT arrays (AuNP-TiNT arrays) were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction, and cyclic voltammetry. The results showed that the Au nanoparticles were unif...

Cyclic voltammograms of the aqueous solution containing polyammonium cations and the [Fe(CN)6]4-. anion at a plastic-formed carbon or platinum electrode were recorded. Polyammonium salts comprising quaternary ammonium in the main chain or sub chain and those comprising primary ammonium were tested. Under certain conditions, well-developed anodic and cathodic peak currents with the midpoint pote...

An amperometric biosensor for hydrogen peroxide (H2O2) was developed via an easy and effective enzyme immobilization method with the “sandwich” configuration: ferrocene-chitosan: HRP: chitosan-glyoxal using a glassy carbon electrode as the basic electrode. In order to prevent the loss of immobilized HRP under optimized conditions, the biosensor surface was cross-linked with glyoxal. Ferrocene w...

Mediatorless, electrochemically driven, redox transformations of T1 (type 1) and T2 copper sites in Trametes hirsuta laccase were studied by cyclic voltammetry and spectroelectrochemical redox titrations using bare gold electrode. DET (direct electron transfer) between the electrode and the enzyme was observed under anaerobic conditions. From analysis of experimental data it is concluded that t...

Enzyme-modified microelectrodes were developed for the indirect amperometric detection of acetylcholine and choline following separation by capillary electrophoresis. Electrodes were prepared by first sequentially electrodepositing polypyrrole and polytyramine from the monomers on a 200-microm platinum electrode. The polymer bilayer provides enhanced selectivity and pendant amino groups for cov...