Electrodes switchable

The brief discussion presented suggests that tanplate-synthesized porous carbons with carefully controlled pore structure may soon find applications in the immobilization of biomolecules (proteins, enzymes, and vitamins) and in bioconversion, reversible amperometric immunosensors, regeneration of enzyme electrodes, switchable biofuel cells, and artificial kidneys [359]. 

Over the past two decades, sustained advances in chemical modification of the electrodes have given us a large variety of electrodes, switchable by various physical and/or chemical signals between electrochemically active and inactive... 

MODIFIED ELECTRODES SWITCHABLE BY APPLIED POTENTIALS RESULTING IN ELECTROCHEMICAL TRANSFORMATIONS AT FUNCTIONAL INTERFACES... 

These types of switchable electrode surfaces have been used to selectively pattern two different cell populations onto a surface [151] and additionally these surfaces can selectively release different cells at different applied potentials [152]. However, it is important to recognize that electrochemically switching a surface from inactive to conjugation and active to conjugation has been well explored with nitro-terminated aryl diazonium salts. In such studies, the application where very anodic potential resulted in a six-electron reduction to an amine [139], to which proteins could be attached [153-155]. The key difference is that the interaction of the biological medium with the surface is controlled by the presence of the antifouling layer. In many ways these electrode surfaces developed by Mrksich and coworkers [150-152, 156] are very similar to the antifouling surfaces with molecular wires discussed in Section 1.4.2 [131, 132, 138, 142]. In both cases the electrode is... 

Electrically switchable rear-view mirrors for cars and trucks have been in commercial production since the early 1990s, the leading company being the Gentex Corporation. The Gentex mirror consists of an ITO-glass surface, with the conductive side inwards, and a reflective metallic surface, spaced less than a millimetre apart. In the gap between these two electrodes is the solution electrolyte that is coloured at the anode by formation of the stable radical cation, similar to Wurster s... 

Figure 6 Cross-section of a switchable grating from photoresist (Strategy 3). By using standard semiconductor fabrication techniques, a cell can be constructed with a holographically patterned central electrode. After filling with LC, the cell can be switched on and off with an electric field applied between the outer unpatterned electrodes.

Light-Switchable Activation of Redox Proteins by Means of Photoisomerizable Command Interfaces Associated with Electrodes... 

Redox enzymes are the active component in many electrochemical enzyme electrode biosensor devices.1821 The integration of two different redox enzymes with an electrode support, in which one of the biocatalysts is photoswitchable between ON and OFF states, can establish a composite multisensor array. The biomaterial interface that includes the photoswitchable enzyme in the OFF state electrochemi-cally transduces the sensing event of the substrate corresponding to the nonphoto-switchable enzyme. Photochemical activation of the light-active enzyme leads to the full electrochemical response, corresponding to the analysis of the substrates of the two enzymes. As a result, the processing of the signals transduced by the composite biomaterial interface in the presence of the two substrates permits the assay of the... 

Electrodes represent an unrivaled platform onto which interfacial supramolecular structures can be assembled. They can be fully characterized before assembly and offer a convenient means to both probe and control the properties of the film. The interest in this area has increased dramatically in recent years because adsorbed monolayers enable both the nature of the chemical functional groups and their topology to be controlled. This molecular-level control allows the effects of both chemical and geometric properties on electron transfer rates to be explored. Moreover, these assemblies underpin technologies ranging from electrocatalysis to redox-switchable non-linear optical materials. 

Self-assembled monolayers of isomerizable compounds can give nst tc surfaces with switchable permeability, thus resulting in different interfacial electrochemistry for a diffusional redox probe. A self-assembled monolayer of 4-cyano-4 -(10-thiodecoxy)stilbene on a Au-electrode demonstrated a higher blocking effect for the [Fe(CN)g] electrochemistry when it was in... 

The immobilization of photoisomerizable host molecules onto an electrode surface can be used for the construction of novel ion-selective electrodes. A photoisomerizable calix[4]arene derivative was incorporated into a polymeric membrane on an electrode surface and the two different isomeric states of the host molecule provided responses selective to Li" or Na" ions depending on the state.Another photoisomerizable host molecule has been constructed from spiropyran and crown-ether subunits. Different binding affinities for Li were found depending on the isomeric state of the photoisomerizable component (26). The researchers suggested that this effect was caused by the coordination of the Li ion to the 0 of the zwitterionic merocyanine-form (Figure 7.29). The photocontrolled host molecules were immobilized in a polymeric film onto an electrode surface, resulting in a photochemically switchable ion-selective electrode. 

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