Biomedical Engineering Reference
In-Depth Information
GR can be used in areas such as: optical [19] or electronic high-speed
devices [20], storage and energy generation [20-22] and also hybrid mate-
rials [23, 24]. Is an ideal material for optoelectronic devices, large-scale
i lms can be synthesized and used for the construction of touch-screen
displays [25]. Manufacture of high frequency transistors [20, 26], photo-
detectors [27], electrochemical sensors [28] and DNA sequencing [29-32]
are just some of other important applications in which GR has found to be
useful.
In this chapter, we focus specially in a specii c but important application
of GR in environmental chemistry. We summarize the research concern-
ing the development of electrochemical (bio)sensors based on GR for the
detection and quantii cation of important chemicals identii ed as strong
contaminants of the environment such as pesticides, phenols, heavy met-
als, among others.
5.1.2 Electrochemical Sensors
In general, sensors are dei ned as devices capable of detecting and quan-
tifying a great variety of chemical species, from gases to biological mac-
romolecules. h ese devices are integrated with two important elements:
a sensing element (recognition) and a signal transducer. h e recognition
element is responsible of the selective detection of the interest analyte,
and the transducer converts a chemical signal to an appropriate sig-
nal that can be used to easily determine the analyte. h e output signal
can be optical, thermal, magnetic or electric (Figure 5.2). h e so-called
Biosensors are sensors that use biological recognition structures such as
proteins (cells, enzymes or antibodies), oligonucleotides, microorgan-
isms and even biological tissue. One of the most important application of
biosensors is the monitoring of biological processes and/or recognition
of biological molecules [33].
e-
M
+
Analyte
e-
M
+
e-
M
+
e-
M
+
e-
Electrode
Figure 5.2
Schematic coni guration of an electrochemical biosensor.
