Biomedical Engineering Reference
In-Depth Information
enemies). Humans usually perceive them as smells and odors. These small
volatile molecules until recently could only be measured with expensive sci-
entific instruments that were not suited for measurements under practical
circumstances on the farm. Nanotechnologies will allow the development of
new principles that not only make them more specific and robust, but also
will make it possible to miniaturize them and produce them in large quanti-
ties, which will reduce costs.
Of course we are familiar with the smell of ripe fruits. These signaling
molecules are produced by plants to attract species that consume the fruits
and thus contribute to the distribution and growing conditions of the seeds.
The smells change as the fruits ripen. By determining the composition of the
smell, the optimal harvesting moment can be determined. Sensors based on
nanotechnology can be used in an orchard or a greenhouse to monitor the
composition of the smell and signal the farmer to start harvesting when the
desired state of ripening has been achieved.
The quantification of volatiles can be used in many more agricultural appli-
cations. As explained before, smells are a common means of communication
between biological species and they usually come into play when important
messages need to be conveyed. The smell of ripe fruits and blooming flowers
is a positive example of this, whereas the smell of disease or pest infestation
is the opposite. The latter is especially important to detect in the early stages
in order to allow small-scale actions for preventing the spread of disease and
possibly make it easier to cure individual plants and animals.
Developments in other areas of nanotechnology, such as wireless com-
munication and energy scavenging, in the near future will provide the
technology to deploy these kinds of monitoring much more easily. In com-
bination with very large-scale production, these technologies could make it
economically possible to employ wireless sensor networks throughout the
greenhouse, stable, or even the plot, to monitor growing conditions and/or
volatiles and to report back to the farm management system when actions
are required. Trials have been conducted to monitor the conditions in potato
crops for detecting phytophthora and specific conditions in vineyards
(Fonseca 2007). In the future, applications of “smart dust,” a military devel-
opment in which large quantities of sand grain-sized devices monitor troop
movements on a battlefield, could be envisioned here.
In animal husbandry applications, the use of RFID (radiofrequency iden-
tification) transponders to identify individual animals is already common
practice. These transponders are not only small enough to be implanted in
the animal's body, but they can also be equipped with sensors to monitor the
health and wellbeing of the animal and/or its production status (e.g., heat
or pregnancy detection). Sensors in the product flow (e.g., milk) can also be
used to monitor the animals and the quality of the product.
The use of chemical sensors to determine the levels of nutrients in the
water that is provided to the crops in greenhouses has been common prac-
tice for some years (Bergveld 2003). These chemFET sensors benefit from
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