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Biosensors An analytical Device

  1. BIOSENSORS
  2. DEFINITION  Self-contained integrated device that is capable of providing specific qualitative or semi-quantitative analytical information using a biological recognition element which is in direct-spatial contact with a transduction element. (IUPAC,1998)  A sensor that integrates a biological element with a physiochemical transducer to produce an electronic signal proportional to a single analyte which is then conveyed to a detector
  3. • What Is a Biosensor? • Biosensor = bioreceptor + transducer • The bioreceptor is a biomolecule that recognizes the target analyte whereas the transducer converts the recognition event into a measurable signal. • Enzyme is a Bioreceptor Need ofbiosensor • Diagnostic Market • Clinical Testing • clinical testing is one of the biggest diagnostic markets • clinical testing products market in excess of 4000 million US$ in the 1990s Specificity • With biosensors, it is possible to measure specific analytes with great accuracy. Speed • analyte tracers or catalytic products can be directly and instantaneously measured Simplicity • receptor and transducer are integrated into one single sensor& the measurement of target analytes without using reagents is possible Continuous monitoring capability • Biosensors regenerate and reuse the immobilized biological recognition element
  4. Simply any device that has specific biochemical reactions to detect chemical compounds in biological samples
  5. COMPONENTS Detector
  6. ELEMENTS OF BIOSENSORS
  7. BIOSENSOR Analyte Sample handling/preparation Detection Signal Analysis Response
  8. THE ANALYTE What do you want to detect? Molecule Protein, toxin, peptide, vitamin, sugar, metal ion Cholera toxin Glucose
  9. SAMPLE HANDLING. (How to deliver the Analyte to the SensitiveRegion?) •(Micro) fluidics •Concentration (increase/decrease) •Filtration/selection
  10. DETECTION/RECOGNITION. Antibody Enzyme Active site Fc Cell Membrane receptors Polymer/Hydrogel Competitive binding (How do you specifically recognise the analyte?) Fab
  11. SIGNAL (How do you know there was a detection?) Common Signalling Principles Optical Electrical Electromechanical Thermal Magnetic Pressure Often the detector is immobilized on a solid support/sensor (The immobilisation permits repeated use of the costlyBiological Molecule.) Specific recognition?
  12. WORKING PRINCIPLE 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 physico- chemical 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. 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 minimised for obtaining Correct Result.  RESPONSE TIME – Time necessary for having 95% of the Response.
  14. 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
  15. TYPES  Optical Biosensors  Resonant Biosensors  Physical biosensors • Piezoelectric Biosensors • Thermometric biosensors  Ion Sensitive Biosensors  Electrochemical Biosensors  Conductometric Sensors  Amperometric  Potentiometric sensors  Impedimetric sensors Sensors
  16. Optical Biosensors.  Colorimetric for colour - Measures change in LightAdsorption.  Photometric for Light Intensity - Detects the Photon output. Resonant Biosensors.  An Acoustic Wave Transducer is coupledwith Bioelement.  Measures the change in Resonant Frequency.
  17. Physical Biosensor Physical biosensors are the most fundamental as well as broadly used sensors. Any detecting device that offers reaction to the physical possessions of the medium was named as a physical biosensor. The physical biosensors are classified into two types namely piezoelectric biosensor and thermometric biosensor.  Piezoelectric Biosensors.  Uses Gold - To detect specific angle at which ȇ waves are emitted when the substance is exposed to laser light/crystals like quartz, which vibrates under the influence of an electric field  Change in Frequency ᾶ Mass ofAbsorbed material
  18. Calorimetric / Thermal Detection Biosensors.  Uses Absorption / Production of Heat. Total heat produced/absorbed is ᾶ Molar Enthalpy/Total No. of molecules in the rn.  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.
  19. There are various types of biological reactions which are connected with the invention of heat, and this makes the base of thermometric biosensors. These sensors are usually named as thermal biosensors Thermometric-biosensor is used to measure or estimate the serum cholesterol. As cholesterol obtains oxidized through the enzyme cholesterol oxidize, then the heat will be produced which can be calculated. Similarly, assessments of glucose, urea, uric acid, and penicillin G can be done with these biosensors.
  20. Ion Sensitive Biosensors.  Are semiconductor FETs with ion- sensitive surface.  Surface Electrical Potential changes when the ions & semiconductors interact.  Measures the Change in Potential. Uses: o pH Detection.
  21. Electrochemical Biosensors. Underlying Principle – Many chem.rns produce or consume ions or ȇs causing some change in the elctrical properties of the solution that can be sensed out & used as a measuring parameter. Uses: Detection of : o Hybridized DNA o DNA- binding Drugs & o Glucose Concentration.
  22. Conductometric 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.
  23.  Amperometric Biosensors.  High Sensitivity Biosensor.  Detects electro active species present in the biological test samples.  Measured Parameter – Current.
  24. Potentiometric Sensors. Working Principle – When ramp voltage is applied to an electrode in solution, a current flow occurs because of electrochemical reactions.  Measured Parameter – Oxidation / reduction Potential of an Electrochemical rn.
  25. 4. Impedimetric Biosensors The EIS (Electrochemical impedance spectroscopy) is a responsive indicator for a broad range of physical as well as chemical properties. A rising trend towards the expansion of Impedimetric-biosensors is being presently observed. The techniques of Impedimetric have been executed to differentiate the invention of the biosensors as well as to examine the catalyzed responses of enzymes lectins, nucleic acids, receptors, whole cells, and antibodies.
  26. OpticalBiosensor • The optical fibers allow detection of analytes on the basis of absorption, fluorescence or light scattering. optical biosensors have the advantages of to in vivo applications and allowing multiple analytes to be detected by using different monitoring wavelengths. Fluorescence-based optical Biosensor
  27. APPLICATIONS
  28. FoodAnalysis. Study of Biomolecules & their Interaction. Drug Development. Crime Detection. Medical Diagnosis (Clin&Lab). Environmental Field Monitoring. Quality Control. Industrial Process Control. Detection Systems for Biological Warfare Agents. Manf. Of Pharmaceuticals & Replacement organs.
  29. 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
  30. ApplicationsofBiosensor continue……. • Biosensor can be used for many analytical problems, ranging from detection of industrial toxins and food contamination to monitoring the density of microbes in an industry and medical diagnostics. • Biosensor for medical diagnostics. • Biosensor for agriculture and food industry. • Biosensor for environment monitoring. • Toxicology tests using biosensor. • Biosensor for general industry. • Biosensor for military and defense industry.
  31. Common healthcare checking Metabolites Measurement Screening for sickness Insulin treatment Clinical psychotherapy & diagnosis of disease In Military Agricultural, and Veterinary applications Drug improvement, offense detection Processing & monitoring in Industrial Ecological pollution control
  32. The DNA capture element instrument- for hereditary diseases Glucometer- for measurement of glucose in blood.
  33. Pregnancy Test •Detects the hCG protein in urine. •Interpretation and data analysis performed by the user. Infectious Disease Biosensor •Data analysis and interpretation performed by a microprocessor
  34. THA K YOU
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