Biomedical Engineering Reference
In-Depth Information
Fig. 14.3
Multi-channel
platform of bioelectronic
nose. In each channel, each
type of olfactory receptor
is combined with a carbon
nanotube FET sensor.
Signals are generated from
the interaction of various
olfactory receptors with
odor molecules
greater the number of sensor integrated in one platform, the better sensor system
is able to identify analytes. In contrast to the conventional electronic nose, using
limited number of chemical sensor array, bioelectronic noses, especially those using
olfactory receptors as a sensing material, are the best example for developing a mul-
tiplexed sensing platform. The bioelectronic nose can utilize lots of biomaterials as
a sensing material, for example, 390 different types of human olfactory receptors,
which are about 40 % out of approximately 1,000 olfactory receptor genes, are func-
tional, and can be used as sensing materials.
Recently, researchers have tried to integrate a large number of olfactory recep-
tors on a single platform to detect a variety of odor molecules simultaneously, and
are developing data processing techniques for the analysis of electrical information
produced from a bioelectronic nose consisting of multi-channel sensors (Fig.
14.3
).
This kind of multi-channel bioelectronic nose can be usefully applied to the analysis
of a whole profile of an odorant mixture. For example, various severe diseases, in-
cluding cancer and diabetes, which produce specific odor molecules as a biomarker,
emit not one specific biomarker but many disease-specific biomarkers through the
exhaled breath. It is very important to identify multiple biomarkers for the exact
diagnosis of these complex diseases. Thus, most target samples to be identified
are complex mixtures containing a variety of different odor components. So, many
analytical methods have been used to recognize patterns of specific signals obtained
from the response of electronic noses to complex mixtures, as well as in order to
detect a specific biomarker. Nevertheless, there is a limit to the number of sensor
elements which can be integrated in a single platform, and a vast array of potential
data to be analyzed. A multi-channel bioelectronic nose would provide a powerful
tool for a great advance in various fields of application of these analytical methods.
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