SMELL OF SUCCESS FOR NANO
INTERNAL GUIDE:Mrs.Sunitha Reddy
What is biosensor?
An analyte is a substance or chemical constituent that is
determined in an analytical procedure like while in blood
glucose testing, the analyte is glucose
A biosensor is a device for the detection of an analyte
which that combines a biological component with a
physicochemical detector component
What is smell of success for Nano
Modern-day doctors may soon start using smell to detect
the early warning signs of different illnesses thanks to
technology that replicates - and improves upon - the human
olfactory system thanks to tiny bioelectronic sensors.
These nanobiosensors will react to a few molecules of
odorant with a very high degree of accuracy . These tiny
bioelectronics sensors represent a „major leap forward‟ in
smell technology .
What is electronic nose?
An electronic nose is a device intended to detect odors or
Over the last decade, “electronic sensing” or “e-sensing”
technologies have undergone important developments from
a technical and commercial point of view. The expression
“electronic sensing” refers to the capability of reproducing
human senses using sensor arrays and pattern recognition
Why electronic nose?
Think of the day when we can retire those
dogs that go around sniffing bags and people
for bombs or drugs, possibly irritating the
people who are being targeted at. Instead,
we have this machine overhead scanning and
“sniffing” for bombs and drugs
An electronic nose basically detects
chemicals in the air, given off by odorous
substances, and finds a pattern of the
chemicals to determine what the smell in the
Human smell system and molecules
The olfatory system has mucus membrane which
contains small segments, nerve cells, the actual sensory
The dendrites, some type of fiber, are covered from the
nerve cells to nasal cavity with a thin layer of moisture.
The smell particles are the source of what we smell.
The moisture dissolves microscopic particles that are
carried in by air from the odor-emitting substance to the
nose The dissolved particles in the mucus stimulate the
olfactory nerve cells through chemical reactions.
Electronic nose working principle
A sample delivery system:enables the generation of the
headspace (volatile compounds) of a sample, which is the
A detection system:which consists of a sensor set, is the
“reactive” part of the instrument. When in contact with
volatile compounds, the sensors react.
A computing system:works to combine the responses of
all of the sensors, which represents the input for the data
As a first step, an electronic nose need to be trained with
qualified samples so as to build a database of reference.
Then the instrument can recognize new samples by
comparing volatile compounds fingerprint to those
contained in its databaseto perform analysis.
Odour handling system
Sensor array chamber
At the space station-for detecting ammonia at few parts of
All of the polymer films on a set of electrodes (sensors)
start out at a measured resistance, their baseline resistance.
If there has been no change in the composition of the air,
the films stay at the baseline resistance and the percent
change is zero
e- e- e- e- e- e-
The Electronic nose smells something
e- e- e-
If a different compound had caused the air to change, the pattern of the
polymer films' change would have been different:
e- e- e-
These include with an example of using dogs to detect to sniff out
bombs, drugs, or fugitives.
Another useful usage of electronic noses is measuring environmental
contamination and detect hazardous chemicals
identifying chemical spills, diagnose strep infection, hunt for truffles,
keep toast from burning, or detecting bad batches of food or drink .
Currently we have humans to test for quality of foods, beverages,
perfumes, tobaccos, washing powders, or even air quality, but using
human testers is expensive and is prone to errors since human sense of
smell may change with age, health, or diet
A company that currently
produces electronic noses
is Cyrano Sciences.
Cyrano Sciences makes
handheld electronic noses
that use a type of polymer
technology licensed from
California Institute of
Technology (CalTech )
Problems in development of e-nose
Firstly classification of smell is based on subjective
perception such as this odor smells fruity, which is
The second major problem is classification of the
physiochemical properties describing each molecule will
be huge .
Smell composing of similar compounds with slightly
different ratios of each of these compounds will result in a
different smell .
Ex:Coffee, tea, and cocoa all contain the same 670
compounds with different ratios and to a normally
functioning nose, each beverage drink smells differently.
In conclusion, electronic noses can be very
beneficial to our everyday life.
. A more precise electronic nose might one day
be used to “smell” viral or bacterial infections.
With the development and usage better electronic
noses, the days using dogs to sniff bombs and
drugs passing through our airports will soon be