Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Upcoming SlideShare
What to Upload to SlideShare
What to Upload to SlideShare
Loading in …3
×
1 of 33

Biosensor

2

Share

Download to read offline

BIOSENSOR, PHARMACEUTICAL BIOTECHNOLOGY, B PHARAM, 6TH SEM
Basic components of Biosensor
Working of Biosensor
Types of Biosensor
Electrochemical biosensor
Optical biosensor
Thermal biosensor
Resonant biosensor
Ion-sensitive biosensor
Applications of Biosensor
Nano sensors
sensing device
Father of the Biosensor
components of BIOSENSOR
BASIC PRINCIPLE OF BIOSENSOR
BIO-ELEMENT
TRANSDUCER
DETECTOR
RESPONSE FROM BIO-ELEMENT
IDEAL BIOSENSOR
BASIC CHARACTERESTICS

Related Books

Free with a 30 day trial from Scribd

See all

Related Audiobooks

Free with a 30 day trial from Scribd

See all

Biosensor

  1. 1. Himanshu Kamboj Assistant Professor
  2. 2. CONTENTS ▪ Introduction ▪ Basic components of Biosensor ▪ Working of Biosensor ▪ Types of Biosensor ▪ Applications of Biosensor
  3. 3. • 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. • Nanosensors are any biological, chemical, or surgical sensory points used to convey information about nanoparticles to the macroscopic world.  medicinal purposes nanoproducts, such as computer chips that work at the nanoscale and nanorobots. INTRODUCTION
  4. 4. INTRODUCTION • A biosensor is a sensing device comprised of a combination of a specific biological element and a transducer. • A “specific biological element” recognizes a specific analyte and the changes in the biomolecule are usually converted into an electrical signal (which is in turn calibrated to a specific scale) by a transducer. • It detects, records, and transmits information regarding a physiological change or process. • It determines the presence and concentration of a specific substance in any test solution.
  5. 5. Father of the Biosensor Professor Leland C Clark Jnr (1918–2005 ) • A device incorporating a biological sensing element either intimately connected to or integrated within a transducer. • Recognition based on affinity between complementary structures like enzyme-substrate, antibody-antigen and receptor-hormone complex. • Selectivity and specificity depend on biological recognition systems connected to a suitable transducer. • It is an analytical device which converts a biological response into an electrical signal. • It detects, records, and transmits information regarding a physiological change or process.
  6. 6. BASIC PRINCIPLE OF BIOSENSOR • The biological material is immobilized and a contact is made between the immobilized biological material and the transducer • The analyte binds to the biological material to form a bound analyte which in turn produces the electronic response that can be measured. • Sometimes the analyte is converted to a product which could be associated with the release of heat, gas (oxygen), electrons or hydrogen ions. The transducer then converts the product linked changes into electrical signals which can be amplified and measured
  7. 7. COMPONENTS ▪ Bio-element ▪ Transducer component
  8. 8. BIO-ELEMENT It is a typically complex chemical system usually extracted or derived directly from a biological organism. Types : • Enzymes • Oxidase • Polysaccharide • Antibodies • Tissue • Nucleic Acid
  9. 9. ▪ Function :- To interact specifically with a target compound i.e. the compound to be detected. ▪ It must be capable of detecting the presence of a target compound in the test solution. ▪ The ability of a bio-element to interact specifically with target compound (specificity) is the basis for biosensor. BIO-ELEMENT
  10. 10. TRANSDUCER ▪ Function : To convert biological response in to an electrical signal. ▪ Types : Electrochemical Optical Piezoelectric
  11. 11. DETECTOR Signals from the transducer are passed to a microprocessor where they are amplified and analyzed. The data is then converted to concentration units and transferred to a display or/and data storage device. PRINCIPLE OF DETECTION • PIEZOELECTRIC: Measures change in mass • ELECTRO-MECHANICAL: Measures change in electric distribution • OPTICAL: Measures change in light intensity • CALORIMETRIC: Measures change in heat
  12. 12. WORKING OF BIOSENSOR Figure:- Schematic Diagram of a Biosensor
  13. 13. • Biosensors basically involve the quantitative analysis of various substances by converting their biological actions into measurable signals. • Generally the performance of the biosensors is mostly dependent on the specificity and sensitivity of the biological reaction, besides the stability of the enzyme
  14. 14. RESPONSE FROM BIO-ELEMENT ■ Heat absorbed (or liberated ) during the interaction. ■ Movement of electrons produced in a redox reaction. ■ Light absorbed (or liberated ) during the interaction. ■ Effect due to mass of reactants or products.
  15. 15. IDEAL BIOSENSOR • The output signal must be relevant to measurement environment. • The functional surface must be compatible with the transducer. • High specificity and selectivity (low interference). • Sufficient sensitivity and resolution • Sufficient accuracy and repeatability • Sufficient speed of response • Sufficient dynamic range. • Insensitivity to environmental interference or their effects must be compensated
  16. 16. 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.
  17. 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 minimised for obtaining Correct Result. • RESPONSE TIME – Time necessary for having 95% of the Response.
  18. 18. TYPES OF BIOSENSOR ▪ Electrochemical biosensor ▪ Optical biosensor ▪ Thermal biosensor ▪ Resonant biosensor ▪ Ion-sensitive biosensor
  19. 19. ELECTROCHEMICAL BIOSENSORS ▪ Principle Many chemical reactions produce or consume ions or electrons which in turn cause some change in the electrical properties of the solution which can be sensed out and used as measuring parameter. ▪ Classification (1) Amperometric Biosensors (2) Conductimetric Biosensors (3) Potentiometric Biosensors continue…
  20. 20. AMPEROMETRIC BIOSENSORS ▪ This high sensitivity biosensor can detect electro-active species present in biological test samples. ▪ Since the biological test samples may not be intrinsically electro-active, enzymes are needed to catalyze the production of radio-active species. ▪ In this case, the measured parameter is current.
  21. 21. CONDUCTIMETRIC BIOSENSORS ■ ■ ■ The measured parameter is the electrical conductance / resistance of the solution. When electrochemical reactions produce ions or electrons, the overall conductivity or resistivity of the solution changes. This change is measured and calibrated to a proper scale(Conductance measurements have relatively low sensitivity.). The electric field is generated using a sinusoidal voltage (AC) which helps in minimizing undesirable effects such as Faradaic processes, double layer charging and concentration polarization.
  22. 22.  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.
  23. 23. POTENTIOMETRIC BIOSENSORS • In this type of sensor the measured parameter is oxidation or reduction potential of an electrochemical reaction. • The working principle relies on the fact that when a ramp voltage is applied to an electrode in solution, a current flow occurs because of electrochemical reactions. • The voltage at which these reactions occur indicates a particular reaction and particular species.
  24. 24. OPTICAL-DETECTION BIOSENSORS • The output transduced signal that is measured is light for this type of biosensor. • The biosensor can be made based on optical diffraction. • In optical diffraction based devices, a silicon wafer is coated with a protein via covalent bonds. The wafer is exposed to UV light through a photo-mask and the antibodies become inactive in the exposed regions. • When the diced wafer chips are incubated in an analyte, antigen- antibody bindings are formed in the active regions, thus creating a diffraction grating. • This grating produces a diffraction signal when illuminated with a light source such as laser. • The resulting signal can be measured.
  25. 25. THERMAL-DETECTION BIOSENSORS  This type of biosensor work on the fundamental properties of biological reactions, namely absorption or production of heat, which in turn changes the temperature of the medium in which the reaction takes place.  They are constructed by combining immobilized enzyme molecules with temperature sensors. When the analyte comes in contact with the enzyme, the heat reaction of the enzyme is measured and is calibrated against the analyte concentration.  The total heat produced or absorbed is proportional to the molar enthalpy and the total number of molecules in the reaction.
  26. 26.  The measurement of the temperature is typically accomplished via a thermistor, and such devices are known as enzyme thermistors. Their high sensitivity to thermal changes makes thermistors ideal for such applications.  Unlike other transducers, thermal biosensors do not need frequent recalibration and are insensitive to the optical and electrochemical properties of the sample.  Common applications of this type of biosensor include the detection of pesticides and pathogenic bacteria.
  27. 27. RESONANT BIOSENSORS ■ It Utilize crystals which undergo an elastic deformation when an electrical potential is applied to them.(Alternating potential (A.C.) produces a standing wave in the crystal at a characteristic frequency.) In this type of biosensor, an acoustic wave transducer is coupled with an antibody (bio-element). When the analyte molecule (or antigen) gets attached to the membrane, the mass of the membrane changes. The resulting change in the mass subsequently changes the resonant frequency of the transducer. This frequency change is then measured. ■ ■
  28. 28. ION-SENSITIVE BIOSENSORS • These are semiconductor FETs having an ion-sensitive surface. • The surface electrical potential changes when the ions and the semiconductor interact.(This change in the potential can be subsequently measured.) • The Ion Sensitive Field Effect Transistor (ISFET) can be constructed by covering the sensor electrode with a polymer layer. This polymer layer is selectively permeable to analyte ions. The ions diffuse through the polymer layer and in turn cause a change in the FET surface potential. • This type of biosensor is also called an ENFET (Enzyme Field Effect Transistor) and is primarily used for pH detection.
  29. 29. GLUCOSE BIOSENSORS  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.
  30. 30. APPLICATIONS OF BIOSENSORS ▪ In food industry, biosensors are used to monitor the freshness of food. ▪ Drug discovery and evaluation of biological activity of new compounds. ▪ Potentiometric biosensors are intended primarily for monitoring levels of carbon dioxide, ammonia, and other gases dissolved in blood and other liquids. ▪ Environmental applications e.g. the detection of pesticides and river water contaminants.
  31. 31. ▪ Determination of drug residues in food, such as antibiotics and growth promoters. ▪ Glucose monitoring in diabetes patients. ▪ Analytical measurement of folic acid, biotin, vitamin B12 and pantothenic acid. ▪ Enzyme-based biosensors are used for continuous monitoring of compounds such as methanol, acetonitrile, phenolics in process streams, effluents and groundwater. ▪ Detection of viral, fungal, bacterial diseases of plants. ▪ In food industry, detection of total microbes & food quantification in soft drinks. ▪ To determine the freshness of other fish, beef & other food items. ▪ Makes Bacteria GLOW by OPTICAL Biosensor
  32. 32. THANK YOU

×