The goal of this chapter is to summarize the recent advances in carbon

nanotubes as a new material for electrochemical sensors. Since their discovery in

1991, carbon nanotubes have received considerable attention in different fields.

Their special geometry and unique electronic, mechanical, chemical and thermal

properties make them a very attractive material for the design of electrochemical

biosensors.

The first application of carbon nanotubes in the preparation of a sensor was

reported by Britto in 1996. Since then, an increasing number of publications

involving sensors based on carbon nanotubes (either single or multi-wall) for

substrates like glucose, lactate, alcohols, phenols, neurotransmitters, aminoacids,

proteins, carbohydrates among others, have been reported. This fact demonstrates

the usefulness of carbon nanotubes for the development of electrochemical

sensors.

The advantages of carbon nanotubes for promoting electron transfer reactions

-with special emphasis in those involving biomolecules-, the different

methodologies for incorporating carbon nanotubes in sensors (either suspended in

solutions, in polymeric films or in composite matrices), the analytical performance

of the resulting biosensors as well as future prospects are discussed in this article.