Outline of Biosensor and its application

1. Biosensor
R. Parthasarathy

2. Introduction
• A biosensor is an analytical device which
converts the biological signal into a
measurable electrical signal.
• Professor Leland C Clark is the father of Biosenor.
Professor Leland C Clark
1918–2005

3. A good biosensor
• It should provide accurate, precise,
reproducible results.
• It should be free from electrical noise.
• It should be cheap, small, portable and capable
of being used by semi-skilled operators.
• The reaction should be independent from
physical parameters (stirring, pH and
temperature).

4. Parts of biosensor
• Bioreceptors
• Transducer
• Signal processor
http://www.intechopen.com/source/html/37959/media/image9.png

5. Bioreceptor
Display
Adapted from www. newtech.tabrizu.ac.ir/Files/Biosensor%20seminar(2).ppt

6. Bioreceptor
The bioreceptor is a biologically derived
material such as tissue, microorganisms,
organelles, cell receptors, enzymes,
antibodies, nucleic acids, etc.
or
Biomimetic component that binds or
recognizes the analyte of interest.

7. Transducer
• When the analyte interacts with the bioreceptor,
change in biological signals such as change in
temperature, electrical charge occurs.
• The transducer transforms these signal into
another signal which is easily measured and
quantified.

8. Biosenor
Calorim-
etric
Optical
Amper
ometric
Piezo-
electric
Potenti-
ometric
Based on the type of transducer the Biosensor
are classified as

9. • Calorimetric biosensors
The heat produced (or absorbed) by the reaction.
• Potentiometric biosensors
Changes in the distribution of charges causing an electrical
potential.
• Amperometric biosensors
Movement of electrons produced in a redox reaction.
• Optical biosensors
Light output during the reaction or a light absorbance
difference between the reactants and products .
• Piezo-electric biosensors
Effects due to the mass of the reactants or products .

10. Signal processors
• Signal processor process the data obtained
from the transducer and displays the result in
user friendly way.
Pregnancy test
Detects the hCG protein in urine.
Example of Biosensor

11. The enzyme glucose oxiadase is used
by blood glucose biosensor to break down of blood glucose.
First it oxidizes glucose and uses two electrons to reduce the FAD
(a component of the enzyme) to FADH2 which in turn is oxidized
by the electrode in a number of steps.
The resulting current is a measure of the concentration of
glucose.
In this case, the electrode is the transducer and the enzyme is the
bioreceptor.
Glucose monitoring device (for diabetes
patients)
Monitors the glucose level in the blood.

12. Applications
There are numerous applications of biosensors with various types.
Some of them are used in
• Monitoring blood glucose level of diabetes patients.
• Detection of Environmental contamination e.g. the detection of
pesticides and heavy metals in river water.
• Remote sensing of airborne pathogens durning epidemic
outbreaks
• Determining levels of toxic substances before and after
bioremediation
• Routine analytical measurement of folic acid, biotin, vitamin B12
• Drug discovery.
• Protein engineering.
• Detection of toxic metabolites such as mycotoxins.

13. References
• http://cdn2.hubspot.net/hub/122959/file-66858649-
jpg/images/dr._leland_clark.jpg
• http://www1.lsbu.ac.uk/water/enztech/biosensors.html
• www.newtech.tabrizu.ac.ir/Files/Biosensor%20seminar(2).ppt
• www.pitt.edu/~super4/36011-37001/36421.ppt
• http://en.wikipedia.org/wiki/Biosensor