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Biosensors

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A biosensor is a device that uses biological components like enzymes, antibodies, or living cells to detect analytes. It consists of a biological recognition element and a physicochemical transducer. A nanobiosensor is a biosensor that operates on the nanoscale. Some key applications of nanobiosensors include detecting DNA, proteins, cells, and biomarkers for medical diagnostics. They can also be used for environmental monitoring, food safety testing, and other areas. Despite their potential, commercialization of biosensors has faced challenges related to biomolecule immobilization, device sensitivity and reproducibility, and cost-effectiveness.

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BIOSENSORS SUB:MOLECULAR BIOLOGY Professor: DR.AZEEM SIR Department: pharmacology

2

 DEFINATION PRINCIPLE OF WORKING COMPONENTS OF BIOSENSOR PRINCIPLE OF DETECTION WORKING OF BIOSENSOR BASIC CHARACTERISTICS NANO BIOSENSORS APPLICATIONS COMPONENTS

3

A BIOSENSOR IS DESCRIBED AS A COMPACT ANALYTICAL DEVICE, INCORPORATING A BIOLOGICAL OR BIOMIMETIC SENSING ELEMENT, EITHER CLOSELY CONNECTED TO, OR INTEGRATED WITHIN, A TRANSDUCER SYSTEM DEFINATION OR

4

Father of biosensor Professor Leland C Clark Jnr (1918–2005) In 1956, The concept of BIOSENSOR was illustrated by an experiment in which glucose oxidase was entrapped at a CLARK ELECTRODE . The decrease in concentration of OXYGEN was proportional to glucose concentration

5

PRINCIPLE OF DETECTION The principle of detection is the specific binding of the analyte of interest to the complementary bio- recognition element immobilised on a suitable support medium. The specific interaction results in a change in one or more physico-chemical properties (pH change, electron transfer, mass change, heat transfer, uptake or release of gases or specific ions) which are detected and may be measured by the transducer

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Biosensors

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ELEMENTS OF BIOSENSOR

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Biosensors

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Biosensors

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BLOCK DIAGRAM OF BIOSENSOR a) Biocatalyst b) Transducer c) Amplifier d) Processor e) Monitor

11

WORKING OF BIOSENSORS Analyte diffuses from the solution to the surface of the Biosensor. Analyte reacts specifically & efficiently with the Biological Component of the Biosensor. This reaction changes the physicochemical properties of the Transducer surface. This leads to a change in the optical/electronic properties of the Transducer Surface. The change in the optical/electronic properties is measured/converted into electrical signal, which is detected.

12

Biosensors

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THE ANALYTE. (What do you want to detect?) Molecule Protein, toxin, peptide, vitamin, sugar, metal ion Cholera toxin Glucose

14

Antibody Enzyme Active site Cell Membrane receptors Polymer/Hydrogel DETECTION RECOGNITION Competitive binding

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SIGNAL Specific recognition

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Analyte diffuses from the solution to the surface of the Biosensor. Analyte reacts specifically & efficiently with the Biological Component of the Biosensor. This reaction changes the physicochmical properties of the Transducer surface. This leads to a change in the optical/electronic properties of the Transducer Surface. The change in the optical/electronic properties is measured/converted into electrical signal, which is detected. WORKING PRINCIPLE

17

BASIC CHARACTERESTICS LINEARITY - Should be High – For the detection of High Substrate Concentration. SENSITIVITY - Value of Electrode Response per Substrate Concentration. SELECTIVITY - Chemical Interference must be minimized for obtaining Correct Result. RESPONSE TIME – Time necessary for having 95% of the Response.

18

TYPICAL SENSING TECHNIQUES Fluorescence. DNA Microarray. SPR (Surface Plasma Resistance). Impedance Spectroscopy. SPM (Scanning Probe Microscopy, AFM, STM). QCM (Quartz Crystal Microbalance). SERS (Surface Enhanced Raman Spectroscopy). Electrochemical.

19

TYPES  Calorimetric/Thermal Detection Biosensors.  Optical Biosensors.  Piezoelectric Biosensors.  Electrochemical Biosensors.  Conductimetric Sensors.  Amperometric Sensors.  Potentiometric Sensors.

20

Calorimetric / Thermal Detection Biosensors. Uses Absorption / Production of Heat. Total heat produced/absorbed is ᾶ Molar Enthalpy/Total No. of molecules in the reaction. Temp. measured by Enzyme Thermistors. Advantages: •No need of Frequent recalibration. •Insensitive to the Optical & Electrochemical Properties of the sample. Uses: Detection of: (1) Pesticides . (2) Pathogenic Bacteria.

21

Schematic diagram of a calorimetric biosensor. The sample stream (a) passes through the outer insulated box (b) to the heat exchanger (c) within an aluminium block (d). From there, it flows past the referen ce thermistor (e) and into the packed bed bioreactor (f, 1ml volume), containing the biocatalyst, where the reaction occurs. The change in temperature is determined by the thermistor (g) and the solution passed to waste (h). External electronics (l) determines the difference in the resistance, and hence temperature, between the thermistors.

22

Reactant Enzyme Heat output -DH (kJ mole-1) Cholesterol Cholesterol oxidase 53 Esters Chymotrypsin 4 - 16 Glucose Glucose oxidase 80 Hydrogen peroxide Catalase 100

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Optical Biosensors. Colorimetric for colour - Measures change in Light Adsorption.  Photometric for Light Intensity - Detects the Photon output. COLORIMETRIC TEST STRIPS : These are disposable single-use cellulose pads impregnated with enzyme and reagents. The most common use of this technology is for whole- blood monitoring in diabetes control. In this case, the strips include glucose oxidase, horseradish peroxidase (EC 1.11.1.7) and a chromogen (e.g. o-toluidine or 3,3',5,5'-tetramethylbenzidine). The hydrogen peroxide, produced by the aerobic oxidation of glucose, oxidising the weakly coloured chromogen to a highly coloured dye. Peroxidase Chromogen(2H) + H2O2 dye + 2H2O The evaluation of the dyed strips is best achieved by the use of portable reflectance meters, although direct visual comparison with a coloured chart is often used

24

PIEZOELECTRIC BIOSENSORS : Piezo-electric crystals (e.g. quartz) vibrate under the influence of an electric field. The frequency of this oscillation (f) depends on their thickness and cut, each crystal having a characteristic resonant frequency. This resonant frequency changes as molecules adsorb or desorb from the surface of the crystal, obeying the relationships where Df is the change in resonant frequency (Hz), Dm is the change in mass of adsorbed material (g), K is a constant for the particular crystal dependent on such factors as its density and cut, and A is the adsorbing surface area (cm2).

25

Biosensors

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Electrochemical Biosensors. Underlying Principle – Many chemical reactions produce or consume ions or electrons causing some change in the electrical properties of the solution that can be sensed out & used as a measuring parameter. Uses: Detection of : oHybridized DNA oDNA- binding Drugs & oGlucose Concentration.

27

CONDUCTIMETRIC SENSORS. MEASURES ELECTRICAL CONDUCTANCE/RESISTANCE OF THE SOLUTION Conductance Measurements have relatively Low Sensitivity. Electrical Field is generated using sinusoidal(ac) voltage, which helps in minimizing undesirable effects like: i. Faradaic processes. ii. Double layer charging & iii. Concentration polarization.

28

AMPEROMETRIC BIOSENSORS  High Sensitivity Biosensor.  Detects electro active species present in the biological test samples.  Measured Parameter – Current Amperometric biosensors function by the production of a current when a potential is applied between two electrodes. They generally have response times, dynamic ranges and sensitivities similar to the potentiometric biosensors. The simplest amperometric biosensors in common usage involve the Clark oxygen electrode.

29

Schematic diagram of a simple amperometric biosensor.  This consists of a platinum cathode at which oxygen is reduced and a silver/silver chloride reference electrode. When a potential of -0.6 V, relative to the Ag/AgCl electrode is applied to the platinum cathode, a current proportional to the oxygen concentration is produced.  This current (I) which is carried between the electrodes by means of a saturated solution of KCl. This electrode compartment is separated from the biocatalyst (here shown glucose oxidase, GOD) by a thin plastic membrane, permeable only to oxygen. The analyte solution is separated from the biocatalyst by another membrane, permeable to the substrate(s) and product(s). This biosensor is normally about 1 cm in diameter but has been scaled down to 0.25 mm diameter using a Pt wire cathode within a silver plated steel needle anode and utilising dip- coated membranes

30

Biosensors

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r POTENTIOMETRIC BIOSENSORS Potentiometric biosensors make use of ion-selective electrodes in order to transduce the biological reaction into an electrical signal. In the simplest terms this consists of an immobilised enzyme membrane surrounding the probe from a pH-meter where the catalysed reaction generates or absorbs hydrogen ions. The reaction occurring next to the thin sensing glass membrane causes a change in pH which may be read directly from the pH- meter's display. Typical of the use of such electrodes is that the electrical potential is determined at very high impedance allowing effectively zero current flow and causing no interference with the reaction.

32

Biosensors

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Biosensors

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ADVANTAGES Highly Specific. Independent of Factors like stirring, pH, etc. Linear response, Tiny & Biocompatible. Easy to Use, Durable. Require only Small Sample Volume. Rapid, Accurate, Stable & Sterilizable.

35

 A biosensor is a measurement system for the detection of an analyte that combines a biological component with a physicochemical detector, and a nano biosensor is a biosensor that on the Nano-scale size Nanobiosensor Transducer Detector Biological Recognition Element (Bioreceptor) Living biological system (cell, tissue or whole organism) Biological molecular species (antibody, enzyme, protein…)

36

Biosensors

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Applications of Nano biosensors Biological Applications  DNA Sensors; Genetic monitoring, disease  Immunosensors; HIV, Hepatitis,other viral diseas, drug testing, environmental monitoring…  Cell-based Sensors; functional sensors, drug testing…  Point-of-care sensors; blood, urine, electrolytes, gases, steroids, drugs, hormones, proteins, other…  Bacteria Sensors; (E-coli, streptococcus, other): food industry, medicine, environmental, other.  Enzyme sensors; diabetics, drug testing, other. Environmental Applications  Detection of environmental pollution and toxicity  Agricultural monitoring  Ground water screening  Ocean monitoring

38

Future Application Cancer Monitoring Nanobiosensors play a very important role for early cancer detection in body fluids. The sensor is coated with a cancer-specific antibody or other biorecognation ligands.The capture of a cancer cell or a target protein yields electrical, optical or mechanical signal for detection. [Professor Calum McNeil detection of cancer proteins that cause MRSA] Identification of Biomarkers ↓ Validation of Cancer Biomarkers ↓ Cancer Biomarkers ↓ Ligands / Probes Developments ↓ Cancer Diagnostics Biosensor ← Detector ↓ Point of Care Cancer Diagnostics

39

Despite optimism for the potential of biosensors, their emergence from the research laboratory to the marketplace has been slow (1). The obstacles to exploitation have been fundamentally related to the presence of biomaterial in the biosensor (immobilisation of biomolecules on transducers, stability of enzymes and antibodies), the development of the sensor device (sensitivity and reproducibility issues) and the integration of biosensors into complete systems. Another major problem for the realistic mass production of biosensors has been the cost factor (1, 2). Unfortunately…

40

APPLICATIONS

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Food Analysis. Study of Biomolecules & their Interaction. Drug Development. Crime Detection. Medical Diagnosis (Clinical & Labaratory). Environmental Field Monitoring. Quality Control. Industrial Process Control. Detection Systems for Biological Warfare Agents. Manufacture Of Pharmaceuticals APPLICATIONS

42

BIOSENSOR FOR AGRICULTURAL & FOOD INDUSTRY. o Detection of viral, fungal, bacterial diseases of plants. o In food industry, detection of total microbes & food quantification in soft drinks. o To determine the freshness of other fish, beef & other food items. o Makes Bacteria GLOW by OPTICAL Biosensor

43

MICROBIOLOGICAL CONTROL IN FOODS  Detection of Salmonella in foods  Detection of E.coli in foods

44

Foodborne pathogens cause economic loss, human suffering and even death. Pathogen detection using culture techniques and bioassays such as ELISA for determining and enumerating pathogens in food is well established. However, these methods are very elaborate, very time consuming and cannot be used as on-site monitoring techniques. In recent years, various types of biosensor have been developed which could help in overall quality control in food processing plants by detecting pathogens within minutes of sampling (1). If pathogens are found with on- or near-line biosensors, then food processors can make decisions more quickly about applying treatments, minimizing the chance of a contaminated final product (1). Detection of Salmonella in foods

45

Ye et al. (1997) described a piezoelectric biosensor for detection of Salmonella typhimurium. The device consists of a quartz crystal wafer sandwiched between two metal electrodes. These electrodes provide a means of connecting the device to an external oscillator circuit that drives the quartz crystal at its resonant frequency. A change in mass on the surface of the electrode thus changes the resonant frequency of the quartz crystal microbalance (QCM) device (Fig. 2). The biosensor responded to concentrations of S.typhimurium in the range of 5.3*105 to 1.2*109 CFUml-1 in 25 min (1).

46

One of the many applications of surface plasmon resonance (SPR) technology is the detection of E. coli O157:H7. Surface plasmon resonance is a quantum optical-electrical phenomenon based on the fact that energy carried by photons of light can be transferred to electrons in a metal. The wavelength of light at which coupling occurs is characteristic of the particular metal and the environment of the metal surface illuminated. This transfer can be observed by measuring the amount of light reflected by the metal surface (1, in, 2). Detection of E.coli in foods

47

Recently an immune-affinity fluorimetric biosensor was developed for detecting and quantifying aflatoxins, a group of chemically related mycotoxins formed by common fungi (Aspergillus flavus, A.parasiticus and A.nomius) found in maize, cottonseed, peanuts, and other nuts, grains and spices. The sample was filtered through a column containing sepharose beads to which the polyclonal aflatoxin- specific antibodies were attached. The beads with the attached bound aflatoxin were subsequently rinsed to remove any unbound or nonspecifically bound impurities and interferon's. After the rinse, an eluant solution was passed through the beads causing the antibodies to release the bound aflatoxin. The analyze was then collected and placed in a fluorimeter. (1,2,3) Detection of infectious disease in products

48

 The increasing demand for on-line evaluation of milk quality directs the industry to look for practical solutions, and biosensors are a promising possibility.  Eshkenazi et al. (2000) developed a multi-enzymatic amperometric biosensor for lactose in fresh raw milk.The characteristics of the biosensor (easy operation, rapid response, long stability) suggested that this method could be used as an economical on-line lactose measurement technique in the milking parlour (1, in). Quality control of MILK

49

microbial contamination results in an increase of the biogenic amine content of fruits and vegetables. Electrochemical biosensors for the determination of the amine content in fruits have been assembled using diamine oxidase (DAO) and polyamine oxidase (PAO) covalently immobilised onto polymeric membranes Both enzymes in the presence of their substrates produced H2O2 that was detected at a platinum electrode (1, in). Quality control of MILK

50

 microbial contamination results in an increase of the biogenic amine content of fruits and vegetables. Electrochemical biosensors for the determination of the amine content in fruits have been assembled using diamine oxidase (DAO) and polyamine oxidase (PAO) covalently immobilised onto polymeric membranes  Both enzymes in the presence of their substrates produced H2O2 that was detected at a platinum electrode (1, in). Quality control of FRUITS

51

 Biosensing principles, such as the amperometric glucose sensor, have been applied in process control and the food industry.  Examples of successful commercialised sensing instruments are the meat check and biocheck sensors.The meat check is a four-electrode array attached to a knife, which can be inserted into meat to measure the glucose gradient immediately below the surface.The size of the gradient is related to microbial activity on the surface of the meat and is regarded as a sound indicator of meat quality.The device provides in seconds what laboratory- based microbiology takes days to test.The biocheck method transformed the glucose sensor into a device capable of detecting and quantifying microorganisms in aqueous solutions.The system transferred electrons from the respiratory pathways of micro-organisms, and detected bacteria in under two minutes (1, in). Quality control of MEAT

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•Concentration of lactic acid is an important parameter for the meat industry as it characterizes the state of fresh meat . Lactic acid is caused by anaerobic glycolysis from glycogen post mortem in muscles. The lactic acid concentration leads to conclusions concerning the pre- mortem metabolic situation, physical stress and deficiency in the meat quality. Bergann et al. (1999) reported an enzymatic biosensor based on immobilised lactatoxidase as bioreceptor and an amperometric transducer. The biosensor estimates lactic acid without special sample preparation, very quickly and at low cost (1 , in).

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Biosensors

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THANK YOU

More Related Content

Biosensors

  • 2.  DEFINATION PRINCIPLE OF WORKING COMPONENTS OF BIOSENSOR PRINCIPLE OF DETECTION WORKING OF BIOSENSOR BASIC CHARACTERISTICS NANO BIOSENSORS APPLICATIONS COMPONENTS
  • 3. A BIOSENSOR IS DESCRIBED AS A COMPACT ANALYTICAL DEVICE, INCORPORATING A BIOLOGICAL OR BIOMIMETIC SENSING ELEMENT, EITHER CLOSELY CONNECTED TO, OR INTEGRATED WITHIN, A TRANSDUCER SYSTEM DEFINATION OR
  • 4. Father of biosensor Professor Leland C Clark Jnr (1918–2005) In 1956, The concept of BIOSENSOR was illustrated by an experiment in which glucose oxidase was entrapped at a CLARK ELECTRODE . The decrease in concentration of OXYGEN was proportional to glucose concentration
  • 5. PRINCIPLE OF DETECTION The principle of detection is the specific binding of the analyte of interest to the complementary bio- recognition element immobilised on a suitable support medium. The specific interaction results in a change in one or more physico-chemical properties (pH change, electron transfer, mass change, heat transfer, uptake or release of gases or specific ions) which are detected and may be measured by the transducer
  • 10. BLOCK DIAGRAM OF BIOSENSOR a) Biocatalyst b) Transducer c) Amplifier d) Processor e) Monitor
  • 11. WORKING OF BIOSENSORS Analyte diffuses from the solution to the surface of the Biosensor. Analyte reacts specifically & efficiently with the Biological Component of the Biosensor. This reaction changes the physicochemical properties of the Transducer surface. This leads to a change in the optical/electronic properties of the Transducer Surface. The change in the optical/electronic properties is measured/converted into electrical signal, which is detected.
  • 13. THE ANALYTE. (What do you want to detect?) Molecule Protein, toxin, peptide, vitamin, sugar, metal ion Cholera toxin Glucose
  • 16. Analyte diffuses from the solution to the surface of the Biosensor. Analyte reacts specifically & efficiently with the Biological Component of the Biosensor. This reaction changes the physicochmical properties of the Transducer surface. This leads to a change in the optical/electronic properties of the Transducer Surface. The change in the optical/electronic properties is measured/converted into electrical signal, which is detected. WORKING PRINCIPLE
  • 17. BASIC CHARACTERESTICS LINEARITY - Should be High – For the detection of High Substrate Concentration. SENSITIVITY - Value of Electrode Response per Substrate Concentration. SELECTIVITY - Chemical Interference must be minimized for obtaining Correct Result. RESPONSE TIME – Time necessary for having 95% of the Response.
  • 18. TYPICAL SENSING TECHNIQUES Fluorescence. DNA Microarray. SPR (Surface Plasma Resistance). Impedance Spectroscopy. SPM (Scanning Probe Microscopy, AFM, STM). QCM (Quartz Crystal Microbalance). SERS (Surface Enhanced Raman Spectroscopy). Electrochemical.
  • 19. TYPES  Calorimetric/Thermal Detection Biosensors.  Optical Biosensors.  Piezoelectric Biosensors.  Electrochemical Biosensors.  Conductimetric Sensors.  Amperometric Sensors.  Potentiometric Sensors.
  • 20. Calorimetric / Thermal Detection Biosensors. Uses Absorption / Production of Heat. Total heat produced/absorbed is ᾶ Molar Enthalpy/Total No. of molecules in the reaction. Temp. measured by Enzyme Thermistors. Advantages: •No need of Frequent recalibration. •Insensitive to the Optical & Electrochemical Properties of the sample. Uses: Detection of: (1) Pesticides . (2) Pathogenic Bacteria.
  • 21. Schematic diagram of a calorimetric biosensor. The sample stream (a) passes through the outer insulated box (b) to the heat exchanger (c) within an aluminium block (d). From there, it flows past the referen ce thermistor (e) and into the packed bed bioreactor (f, 1ml volume), containing the biocatalyst, where the reaction occurs. The change in temperature is determined by the thermistor (g) and the solution passed to waste (h). External electronics (l) determines the difference in the resistance, and hence temperature, between the thermistors.
  • 22. Reactant Enzyme Heat output -DH (kJ mole-1) Cholesterol Cholesterol oxidase 53 Esters Chymotrypsin 4 - 16 Glucose Glucose oxidase 80 Hydrogen peroxide Catalase 100
  • 23. Optical Biosensors. Colorimetric for colour - Measures change in Light Adsorption.  Photometric for Light Intensity - Detects the Photon output. COLORIMETRIC TEST STRIPS : These are disposable single-use cellulose pads impregnated with enzyme and reagents. The most common use of this technology is for whole- blood monitoring in diabetes control. In this case, the strips include glucose oxidase, horseradish peroxidase (EC 1.11.1.7) and a chromogen (e.g. o-toluidine or 3,3',5,5'-tetramethylbenzidine). The hydrogen peroxide, produced by the aerobic oxidation of glucose, oxidising the weakly coloured chromogen to a highly coloured dye. Peroxidase Chromogen(2H) + H2O2 dye + 2H2O The evaluation of the dyed strips is best achieved by the use of portable reflectance meters, although direct visual comparison with a coloured chart is often used
  • 24. PIEZOELECTRIC BIOSENSORS : Piezo-electric crystals (e.g. quartz) vibrate under the influence of an electric field. The frequency of this oscillation (f) depends on their thickness and cut, each crystal having a characteristic resonant frequency. This resonant frequency changes as molecules adsorb or desorb from the surface of the crystal, obeying the relationships where Df is the change in resonant frequency (Hz), Dm is the change in mass of adsorbed material (g), K is a constant for the particular crystal dependent on such factors as its density and cut, and A is the adsorbing surface area (cm2).
  • 26. Electrochemical Biosensors. Underlying Principle – Many chemical reactions produce or consume ions or electrons causing some change in the electrical properties of the solution that can be sensed out & used as a measuring parameter. Uses: Detection of : oHybridized DNA oDNA- binding Drugs & oGlucose Concentration.
  • 27. CONDUCTIMETRIC SENSORS. MEASURES ELECTRICAL CONDUCTANCE/RESISTANCE OF THE SOLUTION Conductance Measurements have relatively Low Sensitivity. Electrical Field is generated using sinusoidal(ac) voltage, which helps in minimizing undesirable effects like: i. Faradaic processes. ii. Double layer charging & iii. Concentration polarization.
  • 28. AMPEROMETRIC BIOSENSORS  High Sensitivity Biosensor.  Detects electro active species present in the biological test samples.  Measured Parameter – Current Amperometric biosensors function by the production of a current when a potential is applied between two electrodes. They generally have response times, dynamic ranges and sensitivities similar to the potentiometric biosensors. The simplest amperometric biosensors in common usage involve the Clark oxygen electrode.
  • 29. Schematic diagram of a simple amperometric biosensor.  This consists of a platinum cathode at which oxygen is reduced and a silver/silver chloride reference electrode. When a potential of -0.6 V, relative to the Ag/AgCl electrode is applied to the platinum cathode, a current proportional to the oxygen concentration is produced.  This current (I) which is carried between the electrodes by means of a saturated solution of KCl. This electrode compartment is separated from the biocatalyst (here shown glucose oxidase, GOD) by a thin plastic membrane, permeable only to oxygen. The analyte solution is separated from the biocatalyst by another membrane, permeable to the substrate(s) and product(s). This biosensor is normally about 1 cm in diameter but has been scaled down to 0.25 mm diameter using a Pt wire cathode within a silver plated steel needle anode and utilising dip- coated membranes
  • 31. r POTENTIOMETRIC BIOSENSORS Potentiometric biosensors make use of ion-selective electrodes in order to transduce the biological reaction into an electrical signal. In the simplest terms this consists of an immobilised enzyme membrane surrounding the probe from a pH-meter where the catalysed reaction generates or absorbs hydrogen ions. The reaction occurring next to the thin sensing glass membrane causes a change in pH which may be read directly from the pH- meter's display. Typical of the use of such electrodes is that the electrical potential is determined at very high impedance allowing effectively zero current flow and causing no interference with the reaction.
  • 34. ADVANTAGES Highly Specific. Independent of Factors like stirring, pH, etc. Linear response, Tiny & Biocompatible. Easy to Use, Durable. Require only Small Sample Volume. Rapid, Accurate, Stable & Sterilizable.
  • 35.  A biosensor is a measurement system for the detection of an analyte that combines a biological component with a physicochemical detector, and a nano biosensor is a biosensor that on the Nano-scale size Nanobiosensor Transducer Detector Biological Recognition Element (Bioreceptor) Living biological system (cell, tissue or whole organism) Biological molecular species (antibody, enzyme, protein…)
  • 37. Applications of Nano biosensors Biological Applications  DNA Sensors; Genetic monitoring, disease  Immunosensors; HIV, Hepatitis,other viral diseas, drug testing, environmental monitoring…  Cell-based Sensors; functional sensors, drug testing…  Point-of-care sensors; blood, urine, electrolytes, gases, steroids, drugs, hormones, proteins, other…  Bacteria Sensors; (E-coli, streptococcus, other): food industry, medicine, environmental, other.  Enzyme sensors; diabetics, drug testing, other. Environmental Applications  Detection of environmental pollution and toxicity  Agricultural monitoring  Ground water screening  Ocean monitoring
  • 38. Future Application Cancer Monitoring Nanobiosensors play a very important role for early cancer detection in body fluids. The sensor is coated with a cancer-specific antibody or other biorecognation ligands.The capture of a cancer cell or a target protein yields electrical, optical or mechanical signal for detection. [Professor Calum McNeil detection of cancer proteins that cause MRSA] Identification of Biomarkers ↓ Validation of Cancer Biomarkers ↓ Cancer Biomarkers ↓ Ligands / Probes Developments ↓ Cancer Diagnostics Biosensor ← Detector ↓ Point of Care Cancer Diagnostics
  • 39. Despite optimism for the potential of biosensors, their emergence from the research laboratory to the marketplace has been slow (1). The obstacles to exploitation have been fundamentally related to the presence of biomaterial in the biosensor (immobilisation of biomolecules on transducers, stability of enzymes and antibodies), the development of the sensor device (sensitivity and reproducibility issues) and the integration of biosensors into complete systems. Another major problem for the realistic mass production of biosensors has been the cost factor (1, 2). Unfortunately…
  • 41. Food Analysis. Study of Biomolecules & their Interaction. Drug Development. Crime Detection. Medical Diagnosis (Clinical & Labaratory). Environmental Field Monitoring. Quality Control. Industrial Process Control. Detection Systems for Biological Warfare Agents. Manufacture Of Pharmaceuticals APPLICATIONS
  • 42. BIOSENSOR FOR AGRICULTURAL & FOOD INDUSTRY. o Detection of viral, fungal, bacterial diseases of plants. o In food industry, detection of total microbes & food quantification in soft drinks. o To determine the freshness of other fish, beef & other food items. o Makes Bacteria GLOW by OPTICAL Biosensor
  • 43. MICROBIOLOGICAL CONTROL IN FOODS  Detection of Salmonella in foods  Detection of E.coli in foods
  • 44. Foodborne pathogens cause economic loss, human suffering and even death. Pathogen detection using culture techniques and bioassays such as ELISA for determining and enumerating pathogens in food is well established. However, these methods are very elaborate, very time consuming and cannot be used as on-site monitoring techniques. In recent years, various types of biosensor have been developed which could help in overall quality control in food processing plants by detecting pathogens within minutes of sampling (1). If pathogens are found with on- or near-line biosensors, then food processors can make decisions more quickly about applying treatments, minimizing the chance of a contaminated final product (1). Detection of Salmonella in foods
  • 45. Ye et al. (1997) described a piezoelectric biosensor for detection of Salmonella typhimurium. The device consists of a quartz crystal wafer sandwiched between two metal electrodes. These electrodes provide a means of connecting the device to an external oscillator circuit that drives the quartz crystal at its resonant frequency. A change in mass on the surface of the electrode thus changes the resonant frequency of the quartz crystal microbalance (QCM) device (Fig. 2). The biosensor responded to concentrations of S.typhimurium in the range of 5.3*105 to 1.2*109 CFUml-1 in 25 min (1).
  • 46. One of the many applications of surface plasmon resonance (SPR) technology is the detection of E. coli O157:H7. Surface plasmon resonance is a quantum optical-electrical phenomenon based on the fact that energy carried by photons of light can be transferred to electrons in a metal. The wavelength of light at which coupling occurs is characteristic of the particular metal and the environment of the metal surface illuminated. This transfer can be observed by measuring the amount of light reflected by the metal surface (1, in, 2). Detection of E.coli in foods
  • 47. Recently an immune-affinity fluorimetric biosensor was developed for detecting and quantifying aflatoxins, a group of chemically related mycotoxins formed by common fungi (Aspergillus flavus, A.parasiticus and A.nomius) found in maize, cottonseed, peanuts, and other nuts, grains and spices. The sample was filtered through a column containing sepharose beads to which the polyclonal aflatoxin- specific antibodies were attached. The beads with the attached bound aflatoxin were subsequently rinsed to remove any unbound or nonspecifically bound impurities and interferon's. After the rinse, an eluant solution was passed through the beads causing the antibodies to release the bound aflatoxin. The analyze was then collected and placed in a fluorimeter. (1,2,3) Detection of infectious disease in products
  • 48.  The increasing demand for on-line evaluation of milk quality directs the industry to look for practical solutions, and biosensors are a promising possibility.  Eshkenazi et al. (2000) developed a multi-enzymatic amperometric biosensor for lactose in fresh raw milk.The characteristics of the biosensor (easy operation, rapid response, long stability) suggested that this method could be used as an economical on-line lactose measurement technique in the milking parlour (1, in). Quality control of MILK
  • 49. microbial contamination results in an increase of the biogenic amine content of fruits and vegetables. Electrochemical biosensors for the determination of the amine content in fruits have been assembled using diamine oxidase (DAO) and polyamine oxidase (PAO) covalently immobilised onto polymeric membranes Both enzymes in the presence of their substrates produced H2O2 that was detected at a platinum electrode (1, in). Quality control of MILK
  • 50.  microbial contamination results in an increase of the biogenic amine content of fruits and vegetables. Electrochemical biosensors for the determination of the amine content in fruits have been assembled using diamine oxidase (DAO) and polyamine oxidase (PAO) covalently immobilised onto polymeric membranes  Both enzymes in the presence of their substrates produced H2O2 that was detected at a platinum electrode (1, in). Quality control of FRUITS
  • 51.  Biosensing principles, such as the amperometric glucose sensor, have been applied in process control and the food industry.  Examples of successful commercialised sensing instruments are the meat check and biocheck sensors.The meat check is a four-electrode array attached to a knife, which can be inserted into meat to measure the glucose gradient immediately below the surface.The size of the gradient is related to microbial activity on the surface of the meat and is regarded as a sound indicator of meat quality.The device provides in seconds what laboratory- based microbiology takes days to test.The biocheck method transformed the glucose sensor into a device capable of detecting and quantifying microorganisms in aqueous solutions.The system transferred electrons from the respiratory pathways of micro-organisms, and detected bacteria in under two minutes (1, in). Quality control of MEAT
  • 52. •Concentration of lactic acid is an important parameter for the meat industry as it characterizes the state of fresh meat . Lactic acid is caused by anaerobic glycolysis from glycogen post mortem in muscles. The lactic acid concentration leads to conclusions concerning the pre- mortem metabolic situation, physical stress and deficiency in the meat quality. Bergann et al. (1999) reported an enzymatic biosensor based on immobilised lactatoxidase as bioreceptor and an amperometric transducer. The biosensor estimates lactic acid without special sample preparation, very quickly and at low cost (1 , in).