Electrochemical sensors electrochemistry

Most readers may not appreciate the impact of electrochemistry and/or electrochemical deposition techniques in medicine. In this chapter we discuss these topics as they relate to medical devices. Emphasis is placed on the often overlooked materials science and surface chemistry aspects of medical devices rather than on the topics, described extensively in the literature, of electrochemical sensors in medical apphca-tions. This chapter is intended to provide the reader with a view of the role in medical devices of electrochemistry in general and electrochemical deposition in particular. It is also intended that the reader gain an appreciation of the future potential role of electrochemistry in devices, particularly in the creation of biomimetic (i.e., biology mimicking) medical devices. 

The literature concerning electrochemical sensors, where lead electrochemistry can be applied, is extremely vast. Therefore, only some representative papers will be presented. More information can be found in recent reviews [420-423]. 

E. Palecek, F. Jelen, Electrochemistry of nucleic acids, in E. Palecek, F. Scheller, J. Wang (Eds.), Electrochemistry of nucleic acids and proteins. Towards electrochemical sensors for genomics and proteomics, Elsevier, Amsterdam, 2005, p. 74. 

The most obvious way to incorporate this chemistry into an electrochemical sensor is to immobilize the enzyme onto an electrode surface and use this electrode to oxidize the hydrogen peroxide produced. An enzymatic sensor of this type was first prepared by Guilbault and Lubrano [91]. Numerous variations on this theme have since appeared, and sensors that employ this electrochemistry are now commercially available. 

Despite the pervasive use of electrochemical sensors and the fundamental importance of electrochemistry as a division of physical and analytical chemistry, this field of study has not traditionally been a favorite of students. One reason for this could be the fact that most electrochemical and electroanalytical textbooks introduce electrochemistry by explaining first the thermodynamics of the electrochemical cell. That approach is bound to discourage all but the brave few. 

Cai, W.J., Zhao, R, Theberge, S.M., Wang, Y., and Luther III, G (2002) Porewater redox species, pH and PCO2 in aquatic sediments—electrochemical sensor studies in Lake Champlain and Sapelo Island. In Environmental Electrochemistry Analysis of Trace Element Biogeochemistry (Taillefert, M., and Rozan, T., eds.), pp. 188-209, American Chemical Society, Washington, DC. 

Refs. [i] Cattrall RW(1997) Chemical sensors. Oxford University Press, Oxford [ii] KahlertH (2002) Potentiometry. In ScholzF (ed) Electro-analytical methods. Springer, Berlin, p 223 [iii] Fabry P, Siebert E (1997) Electrochemical sensors. In Gellings PJ, Bouwmeester HJM (eds) The CRC handbook of solid state electrochemistry. CRC Press, Boca Raton, p 329... 

The best established effect of ultrasound in electrochemistry is the diminution of the diffusion layer and the enhanced limiting currents so produced. This is, per se, of benefit towards sensitivity improvement in electrochemical sensors, and is also the origin of many sonoelectrochemical phenomena. Ultrasound also affects electrode surfaces, which has been exploited as a pretreatment protocol, and has a beneficial effect during electrolysis. 

Borgmann, S., Hartwich, G., Schulte, A., and Schuhmann, W. (2006) Amperometric enzyme sensors based on direct and mediated electron transfer, in Electrochemistry of Nucleic Acids and Proteins. Towards Electrochemical Sensors for Genomics and Proteomics (eds E. Palecek, F. Scheller, and J. Wang), Elsevier, Amsterdam, pp. 599-655. 

Palacek, E., Schneller, F., and Wang, J. (2005) Electrochemistry of Nucleic Acids and Proteins Towards Electrochemical Sensors for Genomics and Proteomics, Elsevier, Amsterdam. 

It is often the case that the impact a given branch of science has upon another requires a rather special vehicle lo become common knowledge. Given that, it is hardly surprising that the impact of electrochemistry on medicine is not yet properly recognized and appreciated by all. Thus, this chapter is designed to focus on electrochemistry as it relates to the medical arena. Specifically, the oft overlooked material-science aspects of medical devices and related power sources that make them tick, are highlighted. This then is the focal point rather than the more often discussed topic of electrochemical sensors in medical devices. 

Electrochemistry of Nucleic Acids and proteins Towards Electrochemical Sensors for genomics and Proteomics, Palecek, E. Scheller, F. Wang, J., Eds., Elsevier Amsterdam, 2005. 

Warsinke, A. Stbcklein, W. Leupold, E. Micheel, E. Scheller, F.W., In In Electrochemistry of Nucleic Acids and proteins Towards Electrochemical Sensors for genomics and Proteomics, Palecek, E. Scheller, F. Wang, J., Eds., Elsevier Amsterdam, 2005, Chapter 14, pp. 451 83. 

As far as electrochemical cells relevant for applications or electrochemical measurements are concerned, we must distinguish between polarization cells, galvanic cells and open-circuit cells, depending on whether an outer current flows and, if so, in which direction this occurs. Table 1.1 provides examples of the purposes for which such cells may be used. In terms of application, we can distinguish between electrochemical sensors, electrochemical actors and galvanic elements such as batteries and fuel cells. These applications offer a major driving force for dealing with solid-state electrochemistry. 

Kale, G.M. and Kurchania, R. (1999) Online electrochemical sensors in molten metal processing technology A review. Ceram. Trans., 92 (Electrochemistry of Glass and Ceramics), 195-220. 

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