Enzyme-based electrochemical biosensors

A biosensor can be defined as a device incorporating a biological sensing element connected to a transducer to convert an observed response into a measurable signal, whose magnitude is proportional to the concentration of a specific chemical or set of chemcials (Eggins 1996). According to the receptor type, biosensors can be classified as enzymatic biosensors, genosensors, immunosensors, etc. Biosensors can be also divided into several categories based on the transduction process, such as electrochemical, optical, piezoelectric, and thermal/calorimetric biosensors. Among these various kinds of biosensors, electrochemical biosensors are a class of the most widespread, numerous and successfully commercialized devices of biomolecular electronics (Dzyadevych et al., 2008). In this chapter, we will focus on the enzyme-based electrochemical biosensors since enzyme electrodes have attracted ever-increasing attentions due to the potential applications in many areas. Enzyme-based electrochemical biosensors have been used widely in our life, such as health care, food safety and environmental monitoring. Health care is the main area in the biosensor applications, such as monitoring blood glucose levels and diabetics by glucose biosensors. Besides, the reliable detection of urea has potential applications for patients with renal disease either at home or in the hospital. Industrial applications for biosensors include monitoring fermentation broths or food processing procedures through detecting concentrations of glucose and other fermentative end products. The sensitive detection of phenolic compound is an important topic for environmental research because phenolic compouds often exist in the wastwaters of many industries, giving rise to problems for our living environment as many of them are very toxic. This chapter is on the enzyme-based electrochemical biosensors, which will begin with a section for enzyme immobilization methods due to their important roles in biosensors. The next section will focus on the recent advances in enzyme-based electrochemical biosensors. Nanomaterials play an important role in recent development of enzyme-based biosensors, thus some popular fabrication methods of nanomaterials will be briefly described towards their applications in nanomaterials synthesis. The emphsis of this chapter is on the recent advances particularly nanomaterials-based biosensors. Some important and intelligent nanomaterials including gold, ZnO, carbon nanotube and polypyrrole will be presented in a way to the current achievements in enzyme-based electrochemical biosensors. The last section of this chapter will discuss challenges currently faced to practical applications. Source: Biosensors, Book edited by: Pier Andrea Serra, ISBN 978-953-7619-99-2, pp. 302, February 2010, INTECH, Croatia, downloaded from SCIYO.COM