Amperometric redox biosensor

J.H. Shin, Y.S. Choi, H.J. Lee, S.H. Choi, J. Ha, I.J. Yoon, H. Nam and G.S. Cha, A planar amperometric creatinine biosensor employing an insoluble oxidizing agent for removing redox-active interference, Anal. Chem., 73 (2001) 5965-5971. 

Co-extensive with the development and application of redox enzyme wired with redox pol5nner to amperometric glucose biosensors by Degani and Heller, Okamoto, Skotheim, Hale and their co-workers reported a similar approach but using different redox polymer to prevent free mediator diffusion into the bulk media [3]. 

Figure 2 Electron transfer events at the surface of a mediated amperometric bacterial biosensor, showing mediators assessing redox sites on the cytoplasmic membrane and within the cell. M[ox], oxidized mediator M[red], reduced mediator.

Pravda, M., Adeyoju, O., Iwuoha, E.I., Vos, J.G., Smyth, M.R., and Vytfas, K. (1995) Amperometric glucose biosensors based on an osmium(2-l-/3-l-) redox polymer-mediated electron transfer at carbon paste electrodes. Electroanalysis, 7, 619-625. 

Hale PD, Boguslavsky LI, Inagaki T, Karan HI, Lee HS, Skotheim TA, Okamoto Y. Amperometric glucose biosensors based on redox polymer-mediated electron transfer. 

P.P. Joshi, S.A. Merchant, Y. Wang, and D.W. Schmidtke, Amperometric biosensors based on redox polymer-carbon nanotube-enzyme composites. Anal. Chem. 77, 3183—3188 (2005). 

As far as the use of ferrocene molecules as amperometric sensors is concerned, they have found wide use as redox mediators in the so-called enzymatic electrodes, or biosensors. These are systems able to determine, in a simple and rapid way, the concentration of substances of clinical and physiological interest. The methodology exploits the fact that, in the presence of enzyme-catalysed reactions, the electrode currents are considerably amplified.61 Essentially it is an application of the mechanism of catalytic regeneration of the reagent following a reversible charge transfer , examined in detail in Chapter 2, Section 1.4.2.5 ... 

A quantitative model for the electrocatalyitic response of enzymatic amperometric biosensors requires consideration of the diffusion of all the involved species and the kinetics of the redox-enzyme catalytic cyde, as is depicted in Figure 2.27. 

In addition, such redox-active organometallic dendrimers are interesting materials with which to modify electrode surfaces. Applications of these dendrimer modified electrodes in the fields of amperometric and potentiometric biosensors, molecular recognition, as well as in electrocatalysis and photoelectrochemistry, clearly represent interesting areas of future research. 

Catalytic Oxidation of NAD(P)H A Continuously Improved Selection of Suitable ROMs This research is triggered hy at least two reasons (1) the importance of NAD(P)H/NAD(P)- - redox couples in biological systems is known, as is known the dependence of oxidation mechanisms on the oxidants [14, 82, 172-174] (2) the possibility of developing amperometric biosensors for NAD(P)+-dependent dehydrogenases. As a consequence, much attention is devoted to the regeneration of these coenzymes in their reduced or oxidized forms for their application in biosensors or in enzymatic synthesis [180]. Here, we are concerned with electrochemical regeneration [181]. 

A further possibility is the use of a mediated amperometric biosensor incorporating activated sludge to provide rapid determination of toxicity [79]. The respiratory activity of this biosensor is determined by using the redox mediator p-benzoquinone. 

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