By Suraj Sheth
When asked “which one of your five
senses would you be most willing to give up?” most people answer “my sense of
smell.” They state that they could not possibly imagine the difficulties of
living life without sight or sound or touch. And many people love food too much
to give up their sense of taste. This leads most people to view their sense of
smell as expendable, and not very important. But what most people don’t realize
is that our sense of smell, the very sense that allows to experience the scent
of freshly cut grass or the scent of warm brownies from the oven, stems from
one of the most complicated systems in the human body.
The
olfactory system (which determines our sense of smell) is extremely intricate,
and has been refined by the process of evolution over millions of years to fit
our needs as a species. It continues to be a major subject of study, and
researchers are continuing to attempt to unravel its complicated origins,
development, and functioning. On February 9th 2016, Dr. Ankur
Saxena, an assistant professor at the University of Illinois Chicago, presented
his research at the Loyola Neuroscience Seminar. He explained how he and his
team discovered that some of the sensory neurons found in the nose had a developmental/embryonic
origin that was different from researchers’ prior predictions. Dr. Saxena had found that microvillous neurons
(which are responsible for sensing pheromones, nucleotides, and possibly amino
acids in the tissue that lines the nasal cavity) develop from an embryonic
region called the neural crest, rather than a region called the olfactory
placode (the embryonic region that many scientists had predicted
would be the origin). His work also revealed that a gene called Sox10 was
critical in the development of these microvillous neurons. These findings may
aid physicians and scientists working to understand neuron renewal in olfactory
tissue, and help get closer to a cure for anosmia (the inability to smell). 
The olfactory system’s ability to identify
complex and subtle smells also continues to be major area of interest. Creating
devices that mimic the olfactory system can help us make sense of our chemical
environment, and could have important applications in a wide range of fields,
from health care to security. On September 9th 2015, researchers at
Rockefeller University and Seoul University, led by Dr. Tai Hyun Park, unveiled
a new “bioelectric nose,” a device that emulates the nose’s ability to identify
two complex compounds, geosmin (GSM) and 2-methylisoborneol (MIB). While the device
may not have the “look” of a human nose, it is similar in its ability to detect
the contamination of drinking water by microbial matter. Bacteria tends to
produce geosmin (which is associated with an “earthy” scent”) and 2-methylisoborneol
(which is associated with a “musty” scent) while growing and dividing in water.
The research team’s goal was to bypass the extensive laboratory methods used by
chemists (such as mass spectrometry) to identify “smell chemicals,” and instead
create a system, based on the structures in neurons in the nose, that could
detect the chemicals relatively quickly at low and high concentrations. The new
electronic “nose” can identify GSM and MIB at low concentrations, even when it
is mixed in with a cloud of other chemicals. The researchers acknowledged that
their two “receptor” system does not approach the complexity of the olfactory
system, which has hundreds of such receptors. But they hope to “scale-up” in
the future, and eventually create a device that can fully imitate the
functioning of a normal human nose.
The “bioelectric nose” and other
devices that use the olfactory system as a model have the potential to redefine
how we view and analyze the world. Most innovations and technologies of the
past have focused exclusively on understanding and interpreting visual
phenomena. By shedding light (pun intended) on the chemical dimension of the
everyday items and interactions around us, these “nose” devices may allow us to
deepen our understanding and conduct a more multifaceted analysis of the
environment. The only question now is:
where will our noses lead us next?
Works Cited:
Elsevier.
"Human-like nose can sniff out contamination in drinking water: New
technology could be used to detect drugs at airports, test food quality and
develop perfumes." ScienceDaily. ScienceDaily, 9 September 2015.
<www.sciencedaily.com/releases/2015/09/150909100607.htm>.
Saxena A, Peng BN, Bronner ME. Sox10-dependent
neural crest origin of olfactory microvillous neurons in zebrafish. eLife (Editor's Choice; Highlighted),
2:e00336 (2013).
Images
found at:
https://www.elsevier.com/__data/assets/image/0014/116141/Bioelectronic-Nose.jpg
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