This document discusses biosensors, which are analytical devices that use biological materials to measure analyte concentration through interactions that are converted into electrical signals. It details the components, working principles, and various types of biosensors, including electrochemical, optical, and piezoelectric sensors, along with their applications in medical diagnostics, environmental monitoring, and food safety. Key features of biosensors such as sensitivity, specificity, and response time are also emphasized.

1. BIOSENSOR
AND ITS
APPLICATION
JISHNU.K.C
M.Sc Biotechnology

2.  Definition
 Features
 Components
 Working principle
 Types
 Applications

3. SENSORS
 A sensor is a device that detects and
responds to some type of input from the
physical environment.
 The specific input could be light, heat,
motion, moisture, ‘pressure, or any one
of a great number of other
environmental phenomena.

4. SENSORS
 A sensor is a converter that
measures a physical quantity and
converts it into a signal which can
be read by an observer or by an
instrument.

5. BIOSENSORS
 These are analytical devices, which measure
concentration of an analyte.
 In biosensors, a biological material ( such as
enzyme, antibody, whole cell, nucleic acid) is used
to interact with the analyte.
 This interaction produces a physical or chemical
change, which is detected by the transducer and
converted to an electrical signal.
 This signal is interpreted and converted to analyte
concentration presentin the sample.

6. CHARACTERISTICS
 Sensitivity
 Simplicity
 Reliability
 Response time
 Speed Utility
 Ease of calibration
 Stability
 Accuracy
 Precision

7. CHARACTERISTICS
 It should be highly specific for the analyte in the presence of other interfering
chemicals or foreign materials .
 The reaction used should be independent of manageable factors like pH,
temperature, stirring, etc.
 The response should be linear over a useful range of analyte concentrations .
 Sensitivity: should detect even low concentration of analyte.
 The device should be tiny and bio-compatible.
 The device should be cheap, small, easy to use and capable of repeated use.
 Stability: should give maximum response over a period of time.

8.  Leland C. Clark, Jr
 The first ‘true’ biosensor was developed
by Leland C. Clark, Jr in 1956 for
oxygen detection.
 He is known as the ‘father of biosensors’
and his invention of the oxygen
electrode bears his name: 'Clark
electrode'

9. Biosensor essentially have 2
components;
1. Biological component :- for
sensing the presence as well as
concentration of an analyte
2. Transducer device :- convert to
chemical/physical/electrical
signals to read.

11. BIOSENSOR:-COMPONENTS
Analyte
Bioreceptor
Transducer
• Substance of interest to be detected
• Molecule specifically recognize the analyte. Eg :- Enzyme, cells, DNA,
Antibodies.
• Process of signal generation (light, pH, heat, charge, mass change)
upon interaction with analyze is known as biorecognition
• Element that converts one forms of energy to another.
• Process of conversion (optical or electrical signal) is known as
signalization.
• Signal is proportional to amount of analyte

12. Electronics
Display
• process transduced signal and prepare it for display
• Using complex electronic circuit which perform signal conditioning
such as amplification and conversion from analogue to digital form
• User interpretation system such as liquid crystal display of
computer or direct printer.

16.  Biosensors are operated based on the principle of signal transduction
and Biorecognition of element.
 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.

17. BIOSENSOR:-WORKING

18. WORKING
1. The sample containing the analyte is first passed through a membrane so as to
eliminate most of the interfering molecules
2. The purified sample is then made to interact with the biological sensor (bioreceptor:
Enzyme, DNA, Cell or Antibody in immobilized form) to yield the desired product
that may be represented as an appropriate chemical entity, heat, electric current or
charge.
3. Intensity of signal is proportional to concentration of analyte.
4. This biochemical/electrical signal is amplified and processed to corresponding by
electronic system and finally read either on a digital panel or recorded on a suitable
recording device.

19. On the basis of the transducer used, biosensor can be
 Electrochemical (Amperometric, Potentiometric, Impedimetric)
 Optical (absorption, reflection, refraction, transmission, surface plasmon,
fluorescence, wave guide)
 Calorimetric
 Piezoelectric (acoustic wave, quartz crystal microbalance)
 Thermoelectric (heat).

20.  On the basis of recognition elements used, biosensor can as
 Enzymatic Biosensors
 DNA or RNA biosensors
 immunosensors (antibody, antigens, or biomarkers)
 Whole-cell sensors
 Microbial biosensors, etc.

21.  Electrochemical Biosensors can be further classified into different types
based on the electrochemical parameters measured:
 Amperometric Biosensor
 Potentiometric Biosensors
 Conductometric Biosensors

22.  Measure the current (typically nA to mA range) resulting
from a chemical reaction (due to catalytic conversion or
the absorption of proteins) of electroactive materials on
transducer (electrode) surface while a constant potential
is applied.
 The working electrode of the amperometric biosensor is
usually a noble metal (gold, titanium, nickel, etc.),
indium tin oxide (ITO), or carbon covered by the
bioreceptor elements.
 Amount of current is directly proportional to the
substrate concentration.
 Glucose biosensor is a good example of amperometric
biosensor

23.  Detect potential from a chemical reaction of electroactive
materials when constant current is applied.
 Measure species such as pH, H*, NH* and other ions, as well
as biomolecules including glucose, urea, penicillin, etc.
 lon-selective field effect transistors (ISFET) are the low cost
devices that can be used for miniaturization of potentiometric
biosensors.
 A good example is an ISFET biosensor used to monitor
intramyocardial pH during open-heart surgery.

24.  Many biological processes involve changes in
the concentrations of ionic species.
 Such changes can be utilised by biosensors
that detect changes in electrical conductivity.
 A typical example of such biosensor ts the urea
sensor, utilising immobilized urease, and used
as a monitor during renal surgery and dialysis.

25.  Utilize principle of optical measurements (absorbance,
fluorescence, luminescence). determining changes in light
absorption between the reactants and products of a
reaction, or measuring the light output by a luminescent
process.
 Enzymes and antibodies are used as the recognition
elements
 Consist of light source, numerous optical components to
generate a light beam with specific characteristics and a
modified sensing head along with a photodetector.
 Fibre optics and optoelectronic transducers are used as
transducer element
 Advantage: these biosensors usually do not require
reference sensors, as the comparative signal can be
generated using the same source of light as the sampling
sensor.

26.  Piezoelectric biosensors are based on acoustics (sound).
piezoelectric biosensors are also called as acoustic
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 present in the sample
solution.
 This leads to increased mass which reduces their
vibrational frequency; this change is used to determine
the amount of antigen present in the sample solution.

27.  Miniaturized biosensors detecting
magnetic micro and nanoparticles in
microfluidic channels using the
magnetoresistance effect have great
potential in terms of sensitivity and
size.

28.  Thermometric Biosensors are also known as
calorimetric biosensors.
 Several biological reactions are associated with the
release of heat.
 Thermometric biosensors measure the temperature
change of the solution containing the analyte
enzymatic reactions.

29.  On the basis of recognition elements used, biosensor can be classified as;
 Enzymatic Biosensors
 DNA or RNA biosensors
 Immunosensors (antibody, antigens, or biomarkers),
 Whole-cell sensors
 Microbial biosensors, etc.

30.  Enzyme are used as recognition
elements Devised on
immobilization methods, i.e.
adsorption of enzymes by van der
Waals forces, ionic bonding or
covalent bonding.
 The commonly used enzymes for
this purpose are oxidoreductases,
polyphenol oxidases, peroxidases,
and aminooxidases

31.  DNA is used as biorecognition elements
(biorecepetor)
 devised on the property that single-strand
nucleic acid molecule is able to recognize and
bind to its complementary strand in a sample.
 The interaction is due to the formation of stable
hydrogen bonds between the two nucleic acid
strands.

32.  Immunological preparation (antibodies) are uses as recognition elements
 Established on the fact that antibodies have high affinity towards their respective
antigens
 Antibodies specifically bind to pathogens or toxins, or interact with components of
the host's immune system

33.  Using microorganisin as recognition element

34.  The tissues for tissue-based sensors arise from plant and animal sources as
recognition elements
 The analyte of interest can be an inhibitor or a substrate of these processes.
 Rechnitz developed the first tissue based sensor for the determination of amino
acid arginine.
 Organelle-based sensors were made using membranes, chloroplasts, mitochondria,
and microsomes.
 High Stability, longer detection time and low specificity.

35.  Detection of ageing of beer: enzymatic biosensors based on cobalt phthalocyanine.
 Detection of pathogens in food: by detecting variation in pH caused by ammonia
(produced by urease - E. coli antibody conjugate) in vegetables using
potentiometric alternating biosensors
 Determining the quality of the food: freshness of meat and fish products and their
quality. By reacting specific chemical entities that develop during the process of
putrefaction (i.e., decomposition) or spoilage of meat products. e Employed in the
dairy industry
1. IN FOOD PROCESSING, MONITORING, FOOD
AUTHENTICITY, QUALITY AND SAFETY

36.  ln fermentation industries & industrial set-up: Biosensors help in the
assay of the concentration of ions.
 The monitoring of final desired products (enzyme, antibody) by products
and cell cultures to obtain the optimum yield of the desired product(s).
e.g., alcohol from molasses,
2, IN INDUSTRIAL AND FERMENTATION INDUSTRY

37.  Monitoring of various pollutants in water.
 Determination of pesticides - potentiometric biosensor.
 analyses of water pollution from herbicide: Amperometric basic sensor
 Remote sensing of admixtures of mine gases in adverse environments.
Monitoring of toxic gases e.g. in chemical industries, in war etc.
 Concentration of ammonia can be defined with microbe biosensor with
cells of type Nitrosomonas spp.
3, ENVIRONMENTAL FIELD

38.  Medical diagnosis eg:- Blood pressure, Blood glucose level.
 Clinical analysis: Quantitative measurement of cardiac markers.
 Measurement of metabolites which serve as indicator of prevailing pathogenic
parameters or metabolic disturbances: glutamate and acetyle choline which are
main causes of degenerative diseases
 hafnium oxide (HfO2): for early stage detection of human interleukin.
 To monitor susceptibility of chemotherapeutic agents
 To monitor Respiratory gases e.g., medical oxygen.
 In organ replacement procedure like artificial pancreas
4, MEDICAL FIELD

39.  Pregenency kit
 Smartband

40.  A lab on a chip (LOC) is a device that
integrates one or several laboratory fucntions on
a single chip of only few millimeters to a few
square centimeters in size.
 Basically, LOC integrate microfluidics,
nanosensors, microelectrics, biochemistry and
electronic components on th same chip.
5, LAB ON CHIP (LOC)

41.  In pharmaceutical industry for monitoring chemical parameters in
the production process (in bioreactors).
 Affinity biosensors for high-throughput screening of bioprocess-
produced antibodies and for drug screening.
 Oligonucleotide-immobilized biosensors for interactions studies
between a surface linked DNA with the target drug.
6, Drug Discovery and Drug Analysis

42.  Photonic biosensors can detect tumor cell in a urine sample to an ultra-sensitivity
level .
 Epigenetic modifications are detected after exploitation of integrated optical
resonators (eg., post-translational modifications in histone and DNA methylation)
using body fluids of patients suffering from cancer or other ailments.
 The ultimate goal is to detect any biochemical and biophvsical signal associated
with a specific disease at the level of a single molecule or cell.
 They can be integrated into other technologies such as lab-on-a chip to facilitate
molecular diagnostics.
 Eg: Detection of microorganisms in various sample: monitoring of metabolites in
body fluids and detection of tissue pathology such as cancer
7, Epigenetics
8, Nano-Biosensors

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