Lecture 1-converted.pdf

Biosensors (BT 440) Course Instructor Dr. Ashish A Prabhu Assistant Professor Department of Biotechnology 1 NIT Warangal  Syllabus  Unit 1:General principles: A historical perspective; Signal transdu...

Biosensors (BT 440) Course Instructor Dr. Ashish A Prabhu Assistant Professor Department of Biotechnology 1 NIT Warangal  Syllabus  Unit 1:General principles: A historical perspective; Signal transduction; Physico-chemical and biological transducers; Sensor types and technologies, Definitions and Concepts Terminology and working vocabulary; Main technical definitions: calibration, selectivity, sensitivity, reproducibility, detection limits, response time.  Unit 2:Physico-chemical transducers: Electrochemical transducers (amperometric, potentiometric, conductimetric); optical transducers (absorption, fluorescence, SPR); Thermal transducers; piezoelectric transducers.  Unit 3:Biorecognition systems: Enzymes; Oligonucleotides and Nucleic Acids; Lipids (LangmuirBlodgett bilayers, Phospholipids, Liposomes); Membrane receptors and transporters; Tissue and organelles (animal and plant tissue); Cell culture; Immunoreceptors; Chemoreceptors; Limitations & problems. Immobilization of biomolecules.  Unit 4:Biosensor Engineering: Methods for biosensors fabrication: self-assembled monolayers, screen printing, photolithography, micro-contact printing, MEMS.  Unit 5:Engineering concepts for mass production. Application of modern sensor technologies: Clinical chemistry; Test-strips for glucose monitoring; Urea determination.  Unit 6: Implantable sensors for long-term monitoring; Environmental monitoring; Technological process control; Food quality control; Forensic science benefits; Problems & 2 limitations. Course Outcome  Understand biosensing and transducing techniques.  Understand principles of linking cell components and biological pathways with energy transduction, sensing and detection.  Demonstrate appreciation for the technical limits of performance of biosensor  Apply principles of engineering to develop bioanalytical devices and design of biosensors 3 Referred Readings  Donald G. Buerk, Biosensors: Theory and Applications, CRC Press, 2009  Alice Cunningham, Introduction to Bioanalytical Sensors, John Wiley& Sons, 1998.  Brian R. Eggins, Chemical Sensors and Biosensors, John Wiley& Sons, 2003  Recent Publications highlighting the applications of biosensors 4 What is biosensors?  A biosensor is a device that measures biological or chemical reactions by generating signals proportional to the concentration of an analyte in the reaction.  The term ‘‘biosensor’’ was coined by Cammann, and its definition was introduced by IUPAC (International Union of Pure and Applied Chemistry).  Biosensors are employed in applications such as disease monitoring, drug discovery, and detection of pollutants, disease-causing micro-organisms and markers that are indicators of a disease in bodily fluids 5 (blood, urine, saliva, sweat). Nose as a sensor 6 Basic terminologies in biosensors  Analyte: A substance of interest that needs detection.  Bioreceptor: A molecule that specifically Analytes recognizes the analyte is known as a bioreceptor.  Bio-recognition: The process of signal generation (in the form of light, heat, pH, charge or mass change, etc.) upon Bioreceptors interaction of the bioreceptor with the analyte. 7 Basic terminologies in biosensors  Transducer: The transducer is an element that converts one form of energy into another. In a biosensor the role of the transducer is to convert the bio-recognition event into a measurable signal. This process of energy conversion is known as Transducers signalization.  Electronics: This is the part of a biosensor that processes the transduced signal and prepares it for display. Signal Processor  Display: The display consists of a user interpretation system such as the liquid crystal display of a computer or a direct printer that generates numbers or curves understandable by the user. 8 Display Basic Components in biosensors 9 Schematic representation of Biosensor 10  Key Milestones 1956 Leland C. Clark, Biosensors for oxygen determination Amperometric enzyme 1962 electrode for the detection of glucose by Leland Clark Potentiometric biosensor to 1969 detect urea by Guilbault and Montalvo First commercial biosensor was developed by Yellow 1975 Spring Instruments 1992 Handheld blood biosensor by i-STAT  Types of biosensors  Resonant biosensors  Optical biosensors  Thermal biosensors  Ion sensitive biosensors  Electrochemical biosensors: Conductimetric, Amperometric and potentiomentric 12  Coupling of Bio and sensor elements Membrane entrapment Physical Adsoprtion Matrix entrapment Covalent bonding 13  Parameters of the biosensors  Selectivity: Selectivity is the ability of a bioreceptor to detect a specific analyte in a sample containing other admixtures and contaminants.  Reproducibility: Reproducibility is the ability of the biosensor to generate identical responses for a duplicated experimental set-up.  Stability : Susceptibility for the external disturbance  Sensitivity : The minimum amount of analyte that can be detected by a biosensor defines its limit of detection (LOD) or sensitivity.  Linearity: Linearity is the attribute that shows the accuracy of the measured response.  Accuracy  Nature of Solution  Response time  Recovery time  Working life time 14 Applications of Biosensors 15  Application of Biosensors (Contd) 16  Challenges in biosensors research Identification of the market that is interested in a biosensor for a specific analyte of interest. Clear-cut advantages over existing methods for analyses of that analyte. Testing the performance of the biosensor both in use and after storage. Response of a biosensor after 6 months of storage is the absolute minimum for any practical commercial application. Stability, costs and ease of manufacturing each component of the biosensor. Hazards and ethics associated with the use of the developed biosensor. 17  Thank You 18