biosensors in food analysis.pptx

application of Biosensors in food analysis

1. Reza JOIA 1

2. Introduction Biosensors play a pivotal role in modern food analysis, offering rapid and precise detection of various components. By harnessing biological molecules, these innovative devices contribute to ensuring food safety, quality, and authenticity. From detecting contaminants to monitoring freshness, biosensors are indispensable tools in the realm of food analysis. 29-Nov-23 Reza Joia 2

3. What is biosensor? Definition of Biosensor: A biosensor is a receptor-transducer system providing semi-quantitative or quantitative analytical information through a bio-recognition unit. IUPAC Description: Described by IUPAC (2000) as an analytical system integrating a bio-substance with a physiochemical transducer, including thermometric, electrochemical, optical, magnetic, or piezoelectric transducers. Advantages Over Traditional Methods: Rapid Results: Nanosensors offer quicker results compared to traditional methods, especially for foodborne pathogen identification. Versatility: Nanosensors are designed for various analytes relevant to food safety, detecting contaminants such as metal ions, gases, vapors, biomolecules, organic molecules, and foodborne microbes. 29-Nov-23 Reza Joia 3

4. Biosensor components Components of Biosensors: Bio-Elements: Living cells, enzymes, tissues, or antibodies act as bio-elements. Sensing Component: Can be electric potential, electric current, etc. Biosensor Functionality: Bio-Receptor: A biomolecule with the ability to recognize the target analyte. Transducer: Converts the identification event into a quantifiable signal. Integration Methods of Bio and Sensor Components: Physical Adsorption: Based on ionic bonds, hydrogen bonds, hydrophobic, or Van der Waals forces to combine the bio-component with the sensor surface. Membrane Entrapment: Uses a membrane, such as partially permeable, to separate the analyte and bio-component while the sensor is integrated with the biological substance. Entrapment in Matrix: Involves creating a porous encapsulation matrix around the bio-component to bind it to the sensor. Covalent Bonding: The surface of the sensor acts as a reactive group to bond with a bio-component. 29-Nov-23 Reza Joia 4

5. GENERATIONS OF BIOSENSORS First Generation Biosensors: Biocatalyst is immobilized between membranes, fixed to the transducer surface. Membranes serve as a binding platform for the biocatalyst. Second Generation Biosensors: Bio-active compound binds instantly, either covalently or adsorptively , to the transducer surface. Elimination of the semi-permeable membrane simplifies the binding process. Third Generation Biosensors: Biocatalyst is bound to an electric equipment, aiding in signal transduction and amplification. Integration with electric components, such as the gate of a field-effect transistor, enables further miniaturization of nano-biosensors. 29-Nov-23 Reza Joia 5

6. CHARACTERISTICS OF BIOSENSOR Selectivity: Biosensor systems require high specificity, minimizing cross-reactivity with compounds of similar chemical composition. Sensitivity: The ability to detect a wide range of analyte concentrations without the need for extensive sample preparation or cleaning steps. Linearity of Response: The biosensor's response should be proportional and cover concentrations relevant to the intended identification of the specific analyte. Signal Response Reproducibility (SRR): Consistent and reproducible responses are crucial when determining trial samples with similar analyte concentrations. Recovery and Quick Response Time: Rapid response times enable real-time monitoring, and efficient recovery times contribute to the reusability of these devices. Operating Life and Stability: Bio-materials used in biosensors must be interfaced to maintain activity under various environmental and biochemical conditions, ensuring a longer operating life and practical market applicability. 29-Nov-23 Reza Joia 6

7. WORKING PRINCIPLE Recognition and Conversion: Biosensors convert biologically induced recognition events (e.g., antibodies, enzymes) into measurable signals through transducers and processors. Bio-Receptor Diversity: Bio-receptors in biosensors, including microorganisms, tissues, enzymes, antibodies, or nucleic acids, play a vital role in detecting target analytes . Transducer Techniques : Transducers are essential components employing diverse techniques (electrochemical, optical, piezoelectric, thermometric, micromechanical, and magnetic) to transform recognition events into detectable signals. Role in Food Quality Control : Biosensors in food quality control offer rapid and specific assessment of quality factors, contributing significantly to analytical chemistry's role in ensuring food quality. 29-Nov-23 Reza Joia 7

8. WORKING PRINCIPLE 29-Nov-23 Reza Joia 8

9. TYPES OF BIOSENSORS Biosensors utilize various transducers, including thermal, optical, piezoelectric, and electrochemical, converting energy from bio-reactions into detectable signals. Electrochemical Transducers: They operate on electrochemical principles, where chemical reactions on nano-substances generate detectable signals like current, voltage, or impedance, enabling diverse biosensing methods. Amperometric Transducers: Based on steady-state electrical current changes during a consistent potential application, these biosensors, often enzyme-based, detect electrochemical substances related to bio-material interactions. Potentiometric Transducers: These biosensors measure potential changes without current flow. Ion-selective electrodes, relying on potentiometric data, are commonly used, especially in enzyme biosensors. Optical Transducers: Different from electrochemical sensors, optical biosensors detect variations in optical signals, employing methods like Surface Plasmon Resonance (SPR), fluorescence, and absorbance for label-free detection. S urface Plasmon Resonance (SPR) Biosensors: Utilizing evanescent waves, SPR detects changes in refractive index, allowing label-free identification of biological-affinity reactions, with applications in medical diagnostics and environmental detection. 29-Nov-23 Reza Joia 9

10. TYPES OF BIOSENSORS 6. Piezoelectric Transducers: Employing piezoelectricity for mass-sensitive detection, commonly using quartz crystals, these biosensors detect changes in frequency due to mass alterations on the crystal surface. 7. Thermometric Transducers: These biosensors monitor heat changes resulting from biochemical reactions, using sensitive thermistors to detect temperature variations, especially in exothermic enzymatic reactions. 29-Nov-23 Reza Joia 10 Bio-Recognition Layer: Essential for precise analysis, bio-recognition involves specific bio-receptors like enzymes, antibodies, DNA, or entire cells, providing high affinity towards target analytes. - Immobilization Methods: Ensuring effective biosensor operation, biological components are immobilized using techniques such as adsorption, microencapsulation, inclusion, cross-linking, and covalent bonding, each with unique advantages and limitations.

11. Application of biosensors on food analysis Safety of Foods: Detection of xenobiotics (additives, fertilizers, pesticides, drugs) and contaminants (PCBs, dioxins, PAHs, biotoxins, heavy metals). Identification of bacterial toxins (marine toxins, mycotoxins). Pathogen detection (viruses, protozoa, bacteria). Food Quality: - Analysis of food composition , Ensuring food safety, Measurement of organophosphate pesticides ,monitoring amino acids (fermentation) and sugars (pasteurization and fermentation). Detection of Microorganisms: Rapid and efficient detection of pathogenic microorganisms like L. monocytogenes, E. coli, Salmonella species using immunosensors and aptamer-based electrochemical biosensors. Biosensors for estimating oxygen stress in microbes, improving food safety under different packaging conditions. Quality Control of Modified Atmosphere Packages: Biosensors to identify ethanol for detecting less oxygen injury in modified atmosphere packages for vegetables and fruits. Monitoring ethanol accumulation for assessing quality loss in apples, decay in potato tubers, and other applications. 29-Nov-23 Reza Joia 11

12. Types of Biosensors in Food Sector 29-Nov-23 Reza Joia 12 Enzyme-Based Biosensors: Utilized in the beverages and liquor industry for determining carbohydrates, alcohols, amines, amino acids, phenol amides, etc. Enzymes such as fructose-5-dehydrogenase, glucose oxidase, invertase, alcohol dehydrogenase, and others are used based on the specific food component. Microbial Biosensors: Bioluminescent biosensors, for detecting gene expression in genetically modified cells. Optical biosensors (resonant mirror, ellipsometric , piezoelectric) for direct identification of bacteria. Electrical impedance biosensors for determining the impedance of interfaces in AC steady state. Fluorescence-labeled biosensors using chemiluminescence, colorimetric, fluorescence, electrochemical, or magnetic responses. Flow immune sensors, often based on enzyme-linked immunosorbent assay (ELISA) principles. Microbial Metabolism-Based Biosensors: Microbes transduce metabolic redox reactions to quantify electric signals using mediators and oxidoreductase reactions.

13. Conclusion Biosensors in Food Analysis: Biosensors play a vital role in ensuring food safety, quality, and process automation by detecting contaminants and essential components in various food products. Applications in Food Sector: Biosensors are employed for safety (detecting xenobiotics, toxins, pathogens), quality control (analyzing composition, shelf life, and freshness), and technological monitoring in food processing. Detection of Microorganisms: Biosensors, particularly immunosensors, offer rapid and reliable identification of microorganisms like E. coli, Salmonella, and L. monocytogenes, enhancing food safety. Quality Control in Modified Atmosphere Packages: Nano-biosensors contribute to quality control by detecting indicators like ethanol, preventing quality loss due to inadequate storage conditions in modified atmosphere packaging. Future Perspectives: Ongoing advancements in nano-biosensors hold the potential to revolutionize food quality monitoring, addressing scientific challenges and enabling multiple-analyte identification with remote sensing capabilities. 29-Nov-23 Reza Joia 13

14. Thank you for your attention 29-Nov-23 Reza Joia 14

15. Reza Joia Teacher: Albana vaseli Reza Joia 29-Nov-23 15

16. Introduction electrochemical biosensors utilize a bioreceptor, such as enzymes or antibodies, linked to a transducer to detect specific molecules in a sample. The selective interaction between the biocomponent and the target molecule generates a signal converted into a measurable property by the transducer. This design ensures the biosensor's specificity, responding solely to the intended analyte and minimizing interference from other substances in the sample. 29-Nov-23 Reza Joia 16

17. Classification of biosensors Biosensors can be classified by type of recognition element or type of signal transduction. 29-Nov-23 Reza Joia 17

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19. Classification of electrochemical biosensors chematic diagram of (a) amperometric / voltammetric , (b) potentiometric, (c) conductometric biosensors, and (d) impedimetric biosensor with the relative equivalent circuit [16] ( Cdl = double-layer capacitance of the electrodes, Rsol = resistance of the solution, Cde = capacitance of the electrode, Zcell = impedance introduced by the bound nanoparticles, and Rcell and Ccell are the resistance and capacitance in parallel). 29-Nov-23 Reza Joia 19 Electrochemical biosensors are classified based on transduction principles and corresponding electrochemical techniques into: (a) Potentiometric, (b) Amperometric , (c) Impedimetric, (d) Conductometric, and (e) Voltammetric biosensors. Each category employs specific electrochemical methods to convert the bioreceptor's interaction with the analyte into measurable signals, allowing for diverse applications in analytical and biomedical field

20. Working principle of electrochemical biosensors 1. Biorecognition Keys: Bioreceptors Specific Interaction: Bioreceptors like enzymes, antibodies, nucleic acids, and aptamers enable specific interactions with target analytes, ensuring selective signal generation. Diverse Recognition Elements: Synthetic aptamers, DNA, proteins, and viruses enhance sensor selectivity, especially in food analysis. Innovative Bioconjugation: Advanced bioconjugation techniques improve biomolecule immobilization on electrodes, enhancing biosensor stability. 2. Sensing Materials and Electrodes Critical Transducer Role: The transducer significantly impacts biosensor performance, including sensitivity and response time. Electrode Surface Properties: Surface characteristics, electron transfer rate, and mass transfer influence signal production. Nanomaterial Integration: Introduction of nanomaterials enhances sensitivity by providing a high surface area-to-volume ratio, strengthening biomolecule loading capacity. 29-Nov-23 Reza Joia 20

21. Potentiometric Biosensors: Measure change in potential at the working electrode surface upon specific analyte-bioreceptor interaction. Utilize ion-selective electrodes. Widely used for various bioanalytes but generally exhibit lower sensitivities compared to amperometric biosensors. Amperometric Biosensors: Measure current produced at the working electrode during the conversion of electroactive moieties. Current directly relates to oxidation or reduction of the analyte after specific interaction with the bioreceptor. Offer simplicity, ease of use, and relatively high sensitivities, but suffer from poor selectivity and potential interferences. Voltammetric Biosensors: Detect analytes by measuring current during controlled variation of applied potential. Provide highly sensitive measurements and enable simultaneous detection of multiple analytes. Different types include Differential Pulse Voltammetry (DPV), Cyclic Voltammetry (CV), and Square Wave Voltammetry (SWV). 29-Nov-23 Reza Joia 21

22. Conductometric Biosensors: Quantify change in conductance between electrodes due to electrochemical reactions. Measure changes in the conductivity properties of the analyte. Often used to monitor metabolic processes in living biological systems. Impedimetric Biosensors: Measure electrical impedance at the electrode/electrolyte interface with a small sinusoidal excitation signal. Utilize Electrochemical Impedance Spectroscopy (EIS) for effective detection. Provide label-free, highly sensitive, and miniaturized biosensing by correlating the analyte-bioreceptor interaction with impedance changes 29-Nov-23 Reza Joia 22

23. Application of biosensors in food analysis Toxin Detection: Biosensors play a crucial role in identifying toxins in food, offering a rapid and sensitive means to detect contaminants such as bacterial toxins, fungal toxins, and algal toxins. Precision in Shellfish Toxin Monitoring: Electrochemical biosensors, such as aptasensors , contribute to precise monitoring of shellfish toxins like saxitoxin (STX), domoic acid (DA), and okadaic acid (OA), ensuring seafood safety by preventing paralytic shellfish poisoning (PSP) and diarrheic shellfish poisoning (DSP). Mycotoxin Monitoring: Biosensors are instrumental in monitoring mycotoxins, which are natural contaminants produced by fungi in crops. Aflatoxins, known for their carcinogenic properties, are particularly targeted, with biosensors offering innovative strategies for their detection in various food items. Innovative Sensing Strategies: Electrochemical biosensors provide innovative sensing strategies, including aptasensors , enzyme-linked immunosensors, and electrochemiluminescence platforms, enhancing the sensitivity and selectivity of detection methods for toxins and mycotoxins. Real Sample Validation: Biosensors are applied to real food samples, demonstrating their practical utility in ensuring food safety. These sensors are designed to detect toxins and mycotoxins in complex matrices such as seawater, mussels, cereals, and even beverages like beer and wine, providing reliable and applicable results 29-Nov-23 Reza Joia 23

24. Abbreviations: AuE: gold electrode; AuNPs: gold nanoparticles; AuSPE: gold screen-printed electrode; Au-IME: gold interdigitated microelectrodes; CA: chronoamperometry; CF: carbon felt; CNF: carbon nanofibers; CV: cyclic voltammetry; DEP: Disposable electrical printed microarray electrode; DPV: differential pulse voltammetry; EIS: electrochemical impedance spectroscopy; GCE: glassy carbon electrode; GF: graphite felt; GO: graphene oxide; ITO: indium–tin-oxide electrode; MBs: magnetic beads; m-GEC: magnetic graphite-epoxy composite; MWCNTs: multi-walled carbon nanotubes; OSWV: Osteryoung square-wave voltammetry; PPY: polypyrrole; QDs: quantum dots; Pt-IME: platinum interdigitated microelectrodes; SPCE: screen-printed carbon electrode; SWV: square-wave voltammetry; SWASV: square-wave anodic stripping voltammetr 29-Nov-23 Reza Joia 24

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27. Thank you for your attention Reza Joia 29-Nov-23 Reza Joia 27