This article reviews recent progress in the development of ferrocene (Fc)-modified thin films and nanoparticles in relation to their biosensor applications. Redox-active materials in enzyme biosensors commonly use Fc derivatives, which mediate electron transfer between the electrode and enzyme active site. Either voltammetric or amperometric signals originating from redox reactions of Fc are de...

An ultrasensitive electrochemical enzyme immunoassay (EEIA) for the detection of proteins on an 8x8 array is described. The assay is based on wired enzyme technology. Briefly, capture antibody was covalently immobilized on a self-assembled 11-mercaptoundecanoic acid (MUA) monolayer coated gold electrode. After incubating with a target protein (antigen), the gold electrode was treated sequential...

Aldehyde biosensors were constructed by cross-linking formaldehyde dehydrogenase (FDH) or aldehyde dehydrogenase (ADH) and bovine serum albumin on the surface of a redox Os-polymer-coated electrode. The prepared aldehyde biosensors responded rapidly (within 30 s) to aldehydes without the addition of a soluble mediator, because the inner redox Os-polymer film effectively mediated the electron tr...

The fabrication of ultrathin-ring electrodes with a diameter of 2 mm and a thickness of 100 nm is established. The ultrathin-ring electrodes provide a large density of pseudo-steady-state currents, and realize pseudo-steady-state amperometry under quiescent conditions without a Faraday cage. Under the limiting current conditions, the current response at the ultrathin-ring electrode can be well ...

The effects of ionic liquids (ILs) on the catalytic activity of enzymes were studied by approaches of electrochemistry and quantum chemistry calculation in this work. Three types of ILs, namely, [bmpyri]BF(4), [bmpyrro]BF(4), and [bmim]BF(4), were selected to address the effects of different types of ILs on the electrocatalytic activity of glucose oxidase (GOx) toward the oxidation of glucose. ...

We report here on a facile enzymatic polymerization protocol to prepare enzyme-poly(thiophene-3-boronic acid) (PTBA) polymeric biocomposites (PBCs) for high-performance mono-/bi-enzyme amperometric biosensing. Horseradish peroxidase (HRP)-catalyzed polymerization of thiophene-3-boronic acid (TBA) monomer was conducted in aqueous solution containing HRP (or plus glucose oxidase (GOx)) by either ...

The scanning electrochemical microscope (SECM) is used to image the activity of enzymes immobilized on the surfaces of disk-shaped carbon-fiber electrodes. SECM was used to map the concentration of enzymatically produced hydroquinone or hydrogen peroxide at the surface of a 33-microm diameter disk-shaped carbon-fiber electrode modified by an immobilized glucose-oxidase layer. Sub-monolayer cove...

• A macroscopic model for enzymatic porous electrode operating in DET mode is derived. The upscaled validated with pore-scale direct numerical simulations. Macroscopic predictions are by comparisons experimental data. This work dedicated to a multi-scale modelling of coupled diffusion and reaction micro-electrode the Direct Electron Transfer mode. physico-electrochemical unsteady developed cons...

A diffusion-kinetic model is presented for an enzyme-modified microcylinder electrode, where the enzyme reaction generates an electro-active product. Simple, approximate expressions are derived for the steady-state current in cases where the enzyme is immobilized in a metallically conducting, or a non-conducting matrix. The model is also extended to the chemical sensor case, of a conducting pol...

Cysteine self assembled monolayer-modified gold (Cys/Au) electrode is used to immobilize superoxide dismutase (SOD) and establish a direct electron transfer between enzyme and electrode surface. However, due to the redox activity of copper ion on Cys monolayer, there would be an ambiguity in electrochemical studies of immobilized SOD on Cys/Au electrode. We designed a series of experiments to c...