A biosensor is a device that uses biological components like enzymes or antibodies to detect analytes. It converts a biological response into an electrical signal. Some key points: - Glucose biosensors are widely used by diabetics to monitor blood glucose levels. They detect glucose using the enzyme glucose oxidase. - Biosensors have applications in food freshness monitoring, environmental monitoring, medical diagnostics, agriculture, and more. - Common types include electrochemical, optical, thermal, and piezoelectric biosensors. Electrochemical biosensors for glucose are a commercial success story.

1. Topic Biosensors
UMAR ALI

2. What is a biosensor???
A biosensor is a analytical device which
convert a biological response into an
electrical signal.

3. FATHER OF THE
BIOSENSORS
• Professor
Leland C
Clark Jnr
1918–2005

4. HISTORY
• ORNL’s has been developing biosensors for
almost a decade
• First ORNL’s developed biosensor was
intend for environmental monitoring
• It is used an antibody response to specific
antigen e.g. bacterium or toxins.

5. Cont….
• Antibody destroy or neutralize organic
poisons
• Thus forming the basis of immunity
• So first biosensor was called as
“immunosensor”

6. Fiber-optic-based biosensors
• In the mid 1980’s T.VO-Dinh and Guy
Griffin
• Used optical based biosensors
• They attached at the end of the optical fiber
an antibody
• React specifically with carcinogen
• When reaction happened flourescence
produce

7. Cont…..
• Fluorescence produce after 5 to10 minutes
• It was transmitted back to the fiber and
measured
• Successful result reported in 1987.

8. Components of biosensors
• A biosensor has five components:
• Biological sensing element
• Transducer
• Signal conditioner
• Data processor
• Signal generator

9. Basic characteristics
• Sensitivity
• Simplicity
• Reliability
• Response time
• Speed Utility
• Ease of calibration
• Stability
• Accuracy
• Precision

10. Principle of operation
• Recognition of the analyte element from the recognizer
• If recognition is made ​, an electrical signal is obtained
• This signal is then processed, or can be filtered
and amplified

11. Enzyme/Metabolic Sensors
• Enzymes are biological catalysts. There are five
main classes of enzymes.
• Oxidoreductases
• Transferases
• Hydrolases
• Lyases
• Isomerases

12. Enzyme/Metabolic
Sensors
Substrate + Enzyme
Substrate-enzyme complex
Product + Enzyme
Substrate consumption or product liberation is
measured and converted into signal.

13. Bioaffinity Sensors
• These sensors are based on binding interactions
between the immobilised biomolecule and the analyte
of interest
• Examples include:
 antibody-antigen interaction
 nucleic acid for complementary sequences
 lectin for sugar.

14. Antibody
Analyte of interest
(antigen)
Interfering species
Antibody-antigen complex

15. Types of Biosensors
Electrochemical
Amphometric
Conductivity
detector
Potentiometric
Magnatic Thermal
Optical
Biosensors
Resonance Piezoelectric

16. Electrochemical Biosensors
• Detection of hybridized DNA
• Drugs
• Gluose concentration
• Classification
 Conductivity Detector
 Potentiometric
 Amphometric

17. Conductivity detector
• Electrical conductance
• Resistance
• Production of ion or electrons

18. POTENTIOMETRIC
• Voltage
• oxidation or Reduction potential

19. Amphometric
• Electro -active species
• Radioactive species
• Analyte concentration
• Independent of the enzyme.

20. Thermal Biosensors
• Absorption or heat production
• Temperature Changes
• Immobilized enzyme molecules
• Temperature sensors

21. Maganetic Biosensors
• Magnetic micro-spheres
• Magneto resistive sensors
• Difference in the electromagnetic field
created by micro-spheres.
Major Limitation
 Signal distortion

23. Optical biosensors
• Biological systems are combined with optical
transducer
• Developed due to laser and low cost optical fibers
• properties of optical fibers that are used in the optical
biosensor are given below:
i-Efficient light delivery
ii-Low cost
iii-Long interaction length
iv-Ability to excite the target molecule but also capture
the emitted light from target molecules

25. Optical biosensors
• Work on the principal of total internal reflection

26. Optical biosensors
i-Determine the diabetes
ii-Fiber optic PH sensor
iii-Fiber optic oxygen sensor

27. Piezoelectric biosensor
• Biosensors based on the “piezoelectric effect “
• Discovered by Curie brothers in the late 19th
century
• A pressure is applied to the piezoelectric material
(e.g Quartz)
• Then a mechanical deformation and displacement
of charges occur

28. Piezoelectric biosensor

29. Resonance biosensor
• Transducer is coupled with the bio-element
e.g antibody
• Detect the change in the resonant frequency

31. • SPR - surface Plasmon resonance:
• Based on the resonance as well as optical phenomena
• Use for the study of surface phenomena
• Monitor protein-protein interactions
• Also study protein-ligand interactions
• Calculate kinetics of bimolecular interactions with
high degree of sensitivity

32. Applications
of
Biosensors

33. Purpose
• The main requirements for a biosensor:
• Identification of a target molecule
• Biological recognition element
• Potential for disposable
• Portable detection systems

34. Examples
• Glucose monitoring in diabetes patients
• Other medical health related targets
• Environmental applications
• Remote sensing of airborne bacteria
• Detection of pathogens
• Determining levels of toxic substances

35. Glucose Monitoring
• Amperometric sensing of glucose by
glucose oxidase
• Oxidizes glucose producing hydrogen
peroxide
• Detected by the electrode.
• Fluorescent glucose biosensors.

37. Interferometric Reflectance Imaging
Sensor(IRIS)
Principle:
• Simple lenses and low-powered, coherent
LED’s
• Sensitivity and reproducibility
• High spatial resolution stems

38. Kohler
illumination
•Randomizes the light
from a single LED
source (called Köhler
illumination)
•Sharp focusing of
incident light

39. Detection
Detection of bacterial
and viral infections

40. Photometric biosensing technique
• Optical interference
techniques
• Imaging of antibodies
• Antibody structure or
using bio-markers
• Reflective substrate
• Measurable by a camera.

41. Conti………..
• Proteins refraction based on their concentration.
• Light is shined on the proteins
• Interference of the light reflected off the proteins
• Sinusoidal variation

42. Military Applications
Dip Stick Test:
• Based on monoclonal antibodies.
• Stable and highly specific
• Unknown hazard detection
• Biorecognition system,
• Matrix of 13-20 proteins
• 95% of all toxin detection.

44. Optical
biosensor
•Lasers to monitor
•Interactions of
biomolecules
• Surface plasmon
resonance
technology

45. Biosensors in food industry
• Measure freshness of raw materials such as
meat, fish, fruits and vegetables.
•
• Detect compounds that provide abnormal
flavors and aromas.
• Indicating microbial growth and food
safety problems.
• Process/quality control food.

47. Biosensors in medical
• Electrochemical biosensors are used low-
cost, operation convenience.
• Detect disease at early stage.
• Identification of target molecule (cancer).
• Forensics for DNA identification.
• Drug discovery.

48. Biosensors in agriculture
• Measure the levels of pesticides,
herbicide and heavy metals in the soil and
ground water.
• Detection of soil diseases.
• Detection of single damaged potato plant
within a field of thousands undamaged
plant.

49. • Fertilizers quality and quantity can be
quickly detected in small quantities
facilitating in pre- and post-harvest
processes.
• Effect of various factors on the respective
yield (temperature ,air ,area,).

50. Environmental applications
• Detection of pesticides and river water
contaminants.
• Concentration of pollutants.
• Remote sensing of airborne bacteria.
• Determining levels of toxic substances
before and after bioremediation.

51. • Detection of toxic metabolites such as
mycotoxins.
• Evaluation of biological activity of new
compounds.
• In waste water treatment .

52. Uses of Biosensors
• Environmental Monitoring
• Military
• Law Enforcement
• Medical

53. Present Applications of Biosensors
• Medical Care (both clinical and laboratory
use)
• The determination of food quality
• The detection of environmental pollutants
• Industrial Process Control

54. Applications (cont’d.)
• Biosensors in process control will be able to measure materials
in the process flow of temperature, pressure and the acidity
readings.
.

55. Conti………
• Detection and determining of organophosphat
• Aanalytical measurement of folic acid biotin, vitamin
B12 and pantothenic acid
• Determination of drug residues in food
• Drug discovery and evaluation of biological activity of
new compounds.
• Protein engineering in biosensors
• Detection of toxic metabolites such as mycotoxins

56. • It is found that biosensors are widely used in environmental
testing by using a “flow-through” system to monitor
wastewater (a flow-through system includes instruments using
surface plasmon resonance).

57. • Biosensors are used in analysing microdialysis
samples

58. • Biosensors are used in monitoring of the
glutamate and acetyl choline, which is the main
cause in neurodegenerative diseases

59. • Biosensors are also used in medical research

60. • Biosensors are used in organ replacement
procedures such as an artificial pancreas
replacement in patient with diabetes

61. • Tumor cells are used as biosensors to monitor the susceptibility
of chemotherapeutic drugs.

62. GLUCOSE BIOSENSOR
• Glucose reacts with glucose
oxidase(GOD) to form gluconic
acid. Two electrons & two
protons are also produced.
• Glucose mediator reacts with
surrounding oxygen to form
H2O2 and GOD.
• Now this GOD can reacts with
more glucose.
• Higher the glucose content,
higher the oxygen consumption.
• Glucose content can be detected
by Pt-electrode.

63. Commercial Glucose Sensors
• Biggest biosensor success story!
• Diabetic patients monitor blood glucose at home
• First made by Medisense (early 1990s), now 5 or more
commercial test systems
• Rapid analysis from single drop of blood
• Enzyme-electrochemical device on a slide

65. Other biosensors
• Cholesterol - based on cholesterol oxidase
• Antigen-antibody sensors - toxic substances, pathogenic
bacteria
• Small molecules and ions in living things: H+, K+, Na+,
CO2, H2O2
• DNA hybridization and damage
• Micro or nanoarrays, optical abs. or fluorescence

66. Applications
• In food industry, biosensors are used to monitor the
freshness of food.
• Environmental applications e.g. the detection of
pesticides and river water contaminants
• Analytical measurement of folic acid, biotin, vitamin
B12 and pantothenic acid
• Determination of drug residues in food, such as
antibiotics and growth promoters