2. Contents
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• Introduction
• Main components of a biosensor
• Working Principle
• Types of Biosensor
• Applications of Biosensor
• Recent Researches
• Conclusion
• Bibliography
3. Introduction
• A biosensor is an analytical device containing an
immobilised biological material (enzyme,
antibody, nucleic acid, hormone or whole cell)
which can specifically interact with an analyte
and produce physical, chemical or electrical
signals that can be measured.
• An analyte is a compound (like glucose, urea,
drug, pesticide etc.) whose concentration has to
be measured.
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4. Main Components of a
Biosensor
• Sensor- sensitive biological material(like tissue,
microorganisms, organelles, cell receptors,
enzymes, antibodies, nucleic acids etc).
• Transducer- converts energy from one form to
another form i.e. biochemical activity into
electrical energy.
• Amplifier- amplifies signal.
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5. 5
• Biosensors are operated based on the principle
of signal transduction.
• Bioreceptor, is allowed to interact with a specific
analyte. The transducer measures this
interaction and outputs a signal. The intensity of
the signal output is proportional to the
concentration of the analyte. The signal is then
amplified and processed by the electronic
system.
Working Principle
6. Types of Biosensor
• Calorimetric Biosensor-
Many enzyme catalysed reactions are exothermic which
may be used as a basis for measuring the rate of rate of
reaction and, hence, the analyte concentration.
The analyte solution is passed through a small packed
bed column containing immobilised enzyme.
Eg- use of glucose oxidase for determination of glucose.
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7. • Potentiometric Biosensors-
These biosensors use ion-selective electrodes to
convert the biological reaction into electronic
signal.
Eg- Urea Biosensor
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8. • Piezoelectric Biosensors-
These biosensors use piezoelectric materials, typically
quartz crystals, in order to generate acoustic waves.
Their surface is usually coated with antibodies which
bind to the complementary antigen present in the sample
solution.
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9. • Optical Biosensors-
These involve determining changes in light
absorption between the reactants and products of a
reaction, or measuring the light output by a
luminescent process.
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10. Applications of Biosensor
• Food Analysis
• Study of Biomolecules and their interactions
• Drug development
• Crime detection
• Industrial process control
• Manufacture of pharmaceuticals and replacement of organs.
• Monitoring glucose level in diabetes patients.
• Protein Engineering
• Agriculture industry
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11. • Biosensors in food industry
Biosensors are used for the detection of pathogens
in food. Presence of E.coli in vegetables, is a
bioindicator of faecal contamination in food. E.coli
has been measured by detecting variation in pH
caused by ammonia using potentiometric
alternating biosensing systems.
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12. Recent Research: Electrochemical
impedimetric biosensors for food safety
• Electrochemical impedimetric biosensors (EIBs) have attracted a great deal of
attention from food safety scientists and administrators.
• EIBs directly detect and measure target molecules with no sample preparation
requirement, and can therefore be used for inline monitoring of hazards in the
food supply chain.
• The sensitivity of EIBs for the detection and measurement of food hazards is
comparable to or better than that of other biosensors and traditional methods.
• Various antibodies that bind directly to food poisoning bacteria, such as
pathogenic Escherichia coli and Salmonella spp., are commercially available,
and EIBs can serve as a universal platform for these pathogens.
Author- Lin D, Pillai RG, Lee WE, Jemere AB. An impedimetric biosensor for E.
coli O157:H7 based on the use of self-assembled gold nanoparticles and protein
G. Microchim. Acta 186: 169 (2019)
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13. Recent Research: Biosensor - Applications
for Food Industry
• A Biosensor may be a self-contained analytical system that responds directly and selectively to
biologically important species; that is, a device or system that detects a biological event.
• Biosensors are defined as indicators of biological compounds that can be as simple as
temperature-sensitive paint or as complex as DNA-RNA probes.
• Food microbiologists are constantly seeking rapid and reliable automated systems for the
detection of biological activity.
• Biosensors provide sensitive, miniaturized systems that can be used to detect unwanted
microbial activity or the presence of a biologically active compound , such as glucose or a
pesticide.
• Immunodiagnostics and enzyme biosensors are two of the leading technologies that have had
the greatest impact on the food industry. The use of these two systems has reduced the time for
detection of pathogens such as Salmonella and has provided detection of biological compounds
such as cholesterol or chymotrypsin.
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14. Author- Edward R. Richter, Siliker Laboratories, Columbus.
Biosensors: applications for dairy food industry. Journal of Dairy Science
Vol. 76, No. 10, 1993.
• The continued development of biosensor technology will soon make available “on-line
quality control” of food production, which will not only reduce cost of food production but
will also provide greater safety and increased food quality.
• In order to define biosensors for use in the food industry , the types of biological events that
might be acceptable for biosensor measurement are need to be known.
• Electrochemical microbial sensors usually detect respiratory activity of the microorganisms.
• This type of biosensor measures the activity of microorganism within the sensor, thus
measuring indirectly the substrate concentration.
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15. Conclusion
A biosensor is a device or an instrument comprising a
biological sensing element coupled to a transducer.
Transducers might include those that are
electrochemical,calorimetric,optical or mechanical.
Although biosensor research has appeared in literature
for 2 decades, few biosensors are commercially
available. Major drawbacks include the delicate nature of
biological component and the miniaturization of the
electrical components. Biosensors like EIBs are great at
gaining attention from food safety scientists. The food
industry will benefit from these developments in rapid
detection of microorganisms and discrete biological
components.
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