application of Biosensors in food analysis

1. Reza JOIA
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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.
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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
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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.
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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.
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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.
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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.
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8. WORKING PRINCIPLE
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9. TYPES OF BIOSENSORS
Biosensors utilize various transducers, including thermal, optical, piezoelectric, and electrochemical, converting
energy from bio-reactions into detectable signals.
1.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.
2.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.
3.Potentiometric Transducers: These biosensors measure potential changes without current flow. Ion-selective
electrodes, relying on potentiometric data, are commonly used, especially in enzyme biosensors.
4.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.
5.Surface 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.
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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.
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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
1.Safety of Foods:
1. Detection of xenobiotics (additives, fertilizers, pesticides, drugs) and contaminants (PCBs, dioxins, PAHs,
biotoxins, heavy metals).
2. Identification of bacterial toxins (marine toxins, mycotoxins).
3. Pathogen detection (viruses, protozoa, bacteria).
2.Food Quality:
- Analysis of food composition , Ensuring food safety, Measurement of organophosphate pesticides
,monitoring amino acids (fermentation) and sugars (pasteurization and fermentation).
3.Detection of Microorganisms:
1. Rapid and efficient detection of pathogenic microorganisms like L. monocytogenes, E. coli, Salmonella
species using immunosensors and aptamer-based electrochemical biosensors.
2. Biosensors for estimating oxygen stress in microbes, improving food safety under different packaging
conditions.
4.Quality Control of Modified Atmosphere Packages:
1. Biosensors to identify ethanol for detecting less oxygen injury in modified atmosphere packages for
vegetables and fruits.
2. Monitoring ethanol accumulation for assessing quality loss in apples, decay in potato tubers, and other
applications.
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12. Types of Biosensors in Food Sector
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1.Enzyme-Based Biosensors:
1.Utilized in the beverages and liquor industry for determining carbohydrates,
alcohols, amines, amino acids, phenol amides, etc.
2.Enzymes such as fructose-5-dehydrogenase, glucose oxidase, invertase, alcohol
dehydrogenase, and others are used based on the specific food component.
2.Microbial Biosensors:
1.Bioluminescent biosensors, for detecting gene expression in genetically modified
cells.
2.Optical biosensors (resonant mirror, ellipsometric, piezoelectric) for direct
identification of bacteria.
3.Electrical impedance biosensors for determining the impedance of interfaces in AC
steady state.
4.Fluorescence-labeled biosensors using chemiluminescence, colorimetric,
fluorescence, electrochemical, or magnetic responses.
5.Flow immune sensors, often based on enzyme-linked immunosorbent assay
(ELISA) principles.
3.Microbial Metabolism-Based Biosensors:
1.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.
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14. Thank you for your
attention
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15. Reza Joia Teacher: Albana vaseli
Reza
Joia
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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.
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17. Classification of biosensors
Biosensors can be classified by type of recognition element or type of signal transduction.
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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).
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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

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
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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). 12/25/202
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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
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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
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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
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27. Thank you for your attention
Reza Joia
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