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Biosensors, Types of Biosensors, Applications of Biosensors, Nanotechnology, Nanobiosensors, Components of Biosensor, Working of Biosensor, Principle of Biosensor, Examples of Biosensor, Advantages of Biosensor, Disadvantages of Biosensor, Limitations of Biosensor, Features of a Biosensor, Calorimetric Biosensors, Potentiometric Biosensors, Acoustic Wave Biosensors, Amperometric Biosensors, Optical Biosensors, Examples of a Nanobiosensor, Lab on a chip,
Applications of Lab on a chip, Glucose Biosensor

Publié dans : Sciences
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  3. 3. INTRODUCTION • A biosensor is an analytical device containing an immobilized biological material (enzyme, antibody, nucleic acid, hormone, organelle 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 (e.g. glucose, urea, drug, pesticide) whose concentration has to be measured. 3
  4. 4. MAIN COMPONENTS OF A BIOSENSOR • Sensor • Transducer • Amplifier • Processor • Display unit 4
  5. 5. • Sensor It is a sensitive biological element (biological material (eg. tissue, microorganisms, organelles, cell receptors, enzymes, antibodies, nucleic acids, etc). • Transducer Transducer is a device that converts energy from one form to another form. In biosensors transducers convert the biochemical activity into electrical energy. 5
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  7. 7. WORKING PRINCIPLE • 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. 7
  8. 8. FEATURES OF A BIOSENSOR a) It should be highly specific for the analyte. b) The reaction used should be independent of manageable factors like pH, temperature, stirring, etc. c) The response should be linear over a useful range of analyte concentrations. d) The device should be tiny and bio-compatible. e) The device should be cheap, small, easy to use and capable of repeated use. 8
  9. 9. TYPES OF BIOSENSOR 1. Calorimetric Biosensors 2. Potentiometric Biosensors 3. Acoustic Wave Biosensors 4. Amperometric Biosensors 5. Optical Biosensors 9
  10. 10. 1. Calorimetric Biosensor Many enzyme catalysed reactions are exothermic, generating heat which may be used as a basis for measuring the rate of reaction and, hence, the analyte concentration. The analyte solution is passed through a small packed bed column containing immobilized enzyme; the temperature of the solution is determined just before entry of the solution into the column and just as it is leaving the column using separate thermistors. An example is the use of glucose oxidase for determination of glucose. 10
  11. 11. 2. Potentiometric Biosensors These biosensors use ion-selective electrodes to convert the biological reaction into electronic signal. Many reactions generate or use H+ which is detected and measured by the biosensor. Urea Biosensor is an example of these biosensors. 11
  12. 12. 3. Acoustic Wave Biosensors (Piezoelectric Biosensors) Acoustic sensors 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. 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. 12
  13. 13. 4. Amperometric Biosensors Amperometric biosensors function by the production of a current when a potential is applied between two electrodes. The magnitude of current being proportional to the substrate concentration. These biosensors are used to measure redox reactions. 13
  14. 14. 5. 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. A most promising biosensor involving luminescence uses firefly enzyme luciferase for detection of bacteria in food or clinical samples. 14
  15. 15. APPLICATIONS OF BIOSENSOR • Food analysis • Study of Biomolecules and their interactions • Drug development • Crime detection • Medical diagnosis • Environmental field monitoring 15 • Industrial process control • Manufacturing of pharmaceuticals and replacement of organs • Monitoring glucose level in diabetes patients • Protein engineering • Wastewater treatment • Agriculture industry
  16. 16. • Biosensors in Food Industry Biosensors are used for the detection of pathogens in food. Presence of Escherichia coli in vegetables, is a bioindicator of faecal contamination in food. E. coli has been measured by detecting variation in pH caused by ammonia (produced by urease–E. coli antibody conjugate) using potentiometric alternating biosensing systems. Enzymatic biosensors are also employed in the dairy industry. 16
  17. 17. • Biosensors in Medical field Glucose biosensors are widely used in clinical applications for diagnosis of diabetes mellitus. A novel biosensor, based on hafnium oxide (HfO2), has been used for early stage detection of human interleukin. These are also used for detection of cardiovascular diseases. 17
  18. 18. • Biosensors in Drug Discovery and Drug Analysis Enzyme‐based biosensors can be applied in the pharmaceutical industry for monitoring chemical parameters in the production process (in bioreactors). Affinity biosensors are suitable for high‐throughput screening of bioprocess‐produced antibodies and for drug screening. Oligonucleotide‐immobilized biosensors for interactions studies between a surface linked DNA and the target drug or for hybridisation studies. 18
  19. 19. • Role of Biosensors in Environmental Monitoring The biosensors find wide application for measurement, estimation and control of water, air and soil contaminants. Determination of the pesticides can be made by potentiometric biosensor. Amperometric basic sensor can be used for analyses of water pollution from herbicide. Concentration of ammonia can be defined with microbe biosensor with cells of type Nitrosomonas sp. 19
  20. 20. • Epigenetics Photonic biosensors have been developed, which can detect tumor cell in a urine sample to an ultra-sensitivity level . Epigenetic modifications are detected after exploitation of integrated optical resonators (e.g., post-translational modifications in histone and DNA methylation) using body fluids of patients suffering from cancer or other ailments. 20
  21. 21. NANOBIOSENSORS • Advances in nanotechnology have led to the development of nanoscale biosensors that have exquisite sensitivity and versatility. • The ultimate goal of nanobiosensors is to detect any biochemical and biophysical 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. • Their applications include detection of microorganisms in various samples, monitoring of metabolites in body fluids and detection of tissue pathology such as cancer. 21
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  23. 23. Advantages of Nanobiosensor  Enhanced sensitivity  Reduced instrumentation size  Improved Speed and specificity in biodiagnostics.  Low cost  Reduction in sensor size provides great versatility for incorporation into multiplexed, transportable, wearable, and even implantable medical devices. 23
  24. 24. Disadvantage of Nanobiosensor  The major problem is that the biomolecule is turned into a colloid by attaching it to a nanocrystal. Because colloids have very different ‘solubility’ from biomolecules, there is always a tendency for coagulation within biological media. 24
  25. 25. EXAMPLE OF NANOBIOSENSOR • Nanowire Biosensors Major sensing components are made of nanowires coated by biological molecules such as DNA molecules, polypeptides, fibrin proteins, and filamentous bacteriophages. The nanomaterials transduce the chemical binding event on their surface into a change in conductance of the nanowire in an extremely sensitive, real time and quantitative fashion. 25
  26. 26. LAB ON A CHIP • 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 the same chip. 26
  27. 27. APPLICATIONS OF LAB ON A CHIP • Concentration gradient generator • Electrophoretic separator • Microbio-reactor •PCR chip for DNA amplification • Quantitative DNA sensor chip (capable of detecting single- pair mismatch) • Flow cytometer Lab-on-a-Chip 27 • Immunoassay Lab-on-a- Chipforbacteria(e.g., E.coli, H. pylori) detection • Real-Time PCR detection chips (fordetecting E. coli, cancers, etc) • Blood sample preparation Lab-on- a-Chip • Cellular analysis Lab-on-a-Chip • Microarrays“(Biochips) DNA microarrays, Protein microarrays
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  29. 29. Use of LOC In HIV detection • 40 million people are infected with HIV.. • 1.3 million of these people receive anti-retroviral treatment. Around 90% of people with HIV have never been tested for the disease. • Measuring the number of CD4+ T lymphocytes in a person’s blood is an accurate way to determine if a person has HIV. • At the moment, flow cytometry is the gold standard for obtaining CD4 counts • Recently such a cytometer was developed for just $5. • In such devices it is possible to quickly diagnose and potentially treat diseases. 29
  30. 30. Use of LOC for Plant Studies • Lab-on-a-chip devices could be used to characterize pollen tube guidance. • Specifically, plant on a chip is a miniaturized device in which pollen tissues and ovules could be incubated for plant sciences studies. 30
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  33. 33. FUTURE OF BIOSENSORS • Biosensor Technology Will Detect—and Potentially Prevent—Illness • Biosensor Technology is on the Verge of Changing how Diabetics Monitor Their Glucose Levels • Biosensor Technology Could Put an End to Drunk Driving • Greater use of nanotechnology and microfluidics (LAB N A CHIP) • Intelligent control of medication delivery • Greater use of home-based monitoring and treatment 33
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  36. 36. THANK YOU 36