Techniques in Biotechnology: Biosensors

1. PTT 104: Introduction to Biotechnology Department of Chemical Engineering Technology, UniMAP Week 5: 10 October 2013 khadijahhanim@unimap.edu.my Techniques in Biotechnology: Biosensors

2. Able to demonstrate important recent advances in methods and applications of biotechnology with regards to microorganisms and plants. Topic: Demonstrate the basic principles of Recombinant DNA Technology and illustrate other methods used in biotechnological field, to include tissue culture, electrophoresis, Polymerase Chain Reaction (PCR) and biosensor. Course Outcome

3. Biosensor Background • What is a Biosensor? • Components of a Biosensor • Principles of Detection • Applications Lecture OutLINE

4. A biosensor is a special type of sensor often used in bioanalysis. Humankind has been performing bioanalysis since the dawn of time, using the sensory nerve cells of the nose to detect scents and those of the tongue to taste dissolved substances. Introduction to Biosensors

5. Analogy with the nose as a sensor (it is actually a biosensor). Biosensors

6. What is biosensor? Bioreceptor: biomolecule that recognizes target analyte Transducer: converts the recognition event into a measurable signal. Biosensor: the two components are integrated into a single sensor. Eg: glucose conc in blood sample can be measured directly by biosensor, by simply dipping the sensor into the sample. Advantages: save time and cost Require no specialized lab skills

8. 1ST Component: Biological Element/Bioreceptor Component that is capable of recognizing a specific target molecule. Must be highly specific, stable under storage conditions, and immobilized. Microorganism Tissue Cell Organelle Nucleic Acid Enzyme Enzyme Component Receptor Antibody

9. 2ND Component: Physiochemical Transducer Acts as an interface, measuring the physical change that occurs with the reaction at the bioreceptor then transforming that energy into measurable electrical output. Typically, this is done by measuring the change that occurs in the bioreceptor reaction. Eg: enzyme glucose oxidase is used as a bioreceptor in a glucose biosensor that catalyzes the following reaction: Glucose + O2 Gluconic acid + H2O2 To measure glucose in a solutions, 3 different transducers can be used: An O2 sensor that measures O2conc A pH sensor that measures acid A peroxidase sensor that measures H2O2 conc.

10. Transducer converts: • O2conc into electrical current • pH change into voltage change • H2O2conc into electrical current.

12. Major requirement for biosensor is the bioreceptor be immobilized in the vicinity of the transducer. • Immobilization can be done via: • Physical entrapment • Chemical attachment • Only minute quantity needed and used repeatedly for measurements. Immobilization of bioreceptor

13. - Performance Characteristics of Biosensor

14. Considerations in Biosensor development

15. Conventional transducers • Major transducers used: • Amperometry: based on H2O2 and O2 measurement • Potentiometry: based on pH or pI measurement • Photometry: utilizing optical fiber Transduction mechanisms in biosensors

16. Biorecognition reactions often generate chemical species that can be measured using electrochemical method. Eg: the reaction product is H2O2 can be measured by a pair of electrodes. When suitable voltage is impressed on one of the electrodes against a ref electrode (Ag/AgCl) the target species (H2O2) is reduced and generate electrical current. amperometry

17. A glass or polymeric membrane electrode is used for measuring membrane potential Resulting the difference in the conc of H+ across the membrane Measured for voltage potentiometry

18. Light from indicator molecule is the measured signal In this method, reactants/products of biorecognition reaction results in colorimetric, fluorescent or luminescent changes and measured using photodetectors. Photometry

20. Examples of biosensor: Pregnancy test: To detects the hCG protein in urine. Glucose monitoring device (for diabetes patients): To monitor the glucose level in the blood. Infectous disease biosensor

21. Examples of biosensor: Biosensor for research works Ring Sensor Smart Shirt

22. Health care/clinical diagnostics • Need a rapid and accurate methods of detection. • Eg:diabetes (type I, type II and gestational): detection of blood sugar levels • Insulin therapy: for treatment of insulin-dependent diabetes (Type I diabetes) Applications of Biosensor

24. Bioreactor control • The productivity depends on bioreactor conditions. • Real-time monitoring of carbon sources, dissolved O2 and CO2 and products of metabolism in fermentation can increased products yield at decreased processing and material cost. • Using biosensors to improve the process productivity. Industrial Process Control

25. Using sensors for chemical and biological warfare agents. Rapid analysis: monitoring hazards due to terrorist activity. Military and homeland security applications

26. Environmental Protection Agency (EPA) Air and Water Monitoring Environmental analytes: biological oxygen demand (BOD), atmospheric acidity, and river water pH, detergent, herbicides, & fertilizer concentrations in drainage and river Environmental monitoring

27. Biosensors using living immobilized microbes play an important part in environmental testing Yeasts such as Trichosporoncutaneumand Artxulaadenivoransare the most frequently used species to measure the organic pollution Microbial Yeast Sensors

28. The idea using microbial sensors developed from the traditional measuring of the Biochemical Oxygen Demand in 5 days By using Microbial Sensors, only 5 minutes are required instead of 5 days. HOW????

29. The living yeast cells are immobilized in a polymer gel and mounted on an oxygen electrode. The sensor measures how much oxygen the “starving” cells are taking up. When clean water, containing non degradable substances, is added, the yeast does not take up additional oxygen.