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ELECTROCHEMICAL
BIOSENSORS
Shiva Lashkari
Chem 4590
Outline
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General overview of electrochemical biosensors.
Two Types of electrochemical biosensors.
Some biomedical applications.
Nanobiosensors.
Summary and conclusion.
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Definition
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An electrochemical biosensor is an analytical device
that
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Converts a biological response to an electric signal;
e.g., via releasing electrons during a reaction.
Measures that electric signal; e.g., measures the
resulting electric current.
Processes the electric signal; e.g., relating the
measured current to the released electrons.
Detects (characterizes) a biological component from
this processed electric signal; e.g., determine the
amount of glucose in the blood.
Electrochemical Biosensors Flowchart
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Analyte
Bioreceptors
(e.g.,
enzymes)
Electrical
Transducer
(e.g.,
Electrode)
Signal
amplification
and
processing
Display
(e.g., a
graph, a
number)
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Electrochemical Biosensor Elements
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Requirements for different parts of biosensor
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Bioreceptor:
Highly specific to the analyte
 Stable
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Bioreceptor & Analyte:
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Their interaction should be independent of physical
parameters; e.g., stirring, pH, and temperature.
Electrical transducer:
The resulting signal must be linear, reproducible over the
concentration range of interest.
 Generates a signal having high signal-to-noise ratio.
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Non-Specialist Market:
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Affordable, portable, easy-to-use, and rapid.
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Advantages and Disadvantages
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Advantage:
 Highly
specific
 Easy miniaturization
 Low detection limit
 Portable
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Disadvantage
 Utilized
enzymes have limited life span, and gradually
lose their activity.
History—Father of Biosensors
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• Professor Clark is
considered as the “father
of biosensors”.
• 1962: Clark and Lyons
described how to make an
amperometric enzyme
electrode for detecting
glucose.
• 1972: First commercial
biosensor (glucose) by
Yellow Springs Instruments.
1918-2005
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Amperometric Transducers
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Electrochemical reaction between the analyte and
bioreceptor generates electric charges.
These electric charges then move and create an
electric current.
This electric current is measured.
This measured electric current is then used to
characterize the analyte.
Glucose Amperometric Biosensor
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Glucose Amperometric Biosensor
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Potentiometric Transducer
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Potentiometric transducers work based
on the idea of a transistor. (A
transistor consists of three terminals)
Electrochemical reaction generates
electric charges.
These electrical charges creates an
electric potential difference between
two ports.
This electric potential difference
creates an electric current between
another two ports.
Field Effect Transistor (FET)
Potential difference between
Gate-Source results in a current
between Source-Drain.
This electric current is then measured.
The measured electric current is then
used to characterize the analyte.
Enzyme FET (En-FET)
Use an enzyme for the gate.
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Penicillin-Sensitive En-FET biosensor
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Nanobiosensor
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Nanotechnology is already being used for
transistor manufacturing; e.g., Apple A8, used
in iphone 6, contains 2 billion transistors.
Nanotechnology enables us to design much
smaller sensor that are much more sensitive
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Some Different Nanobiosensors
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Nanowire FET sensors, Carbon nanotube
electrodes, Quantum dots, Nanoparticle sensors,
etc.
For example, carbon nanotubes (CNTs) are made
from rolled-up graphene sheets.
CNTs can be oxidised. This produces carboxylic
end, which can then be used for attaching
different biomolecules such as DNA, enzymes.
DNA Electrochemical Sensor
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• Such sensors have been fabricated by immobilizing single-stranded DNA (ssDNA) onto an
electrode. Identifying genomic DNA sequences and detecting mutations can be done using
these biosensor; e.g., breast cancer 1 (BRCA1) gene can be detected.
• When the complementary sequence hybridizes with the ssDNA a current signal will be
generated and measured.
• A cationic metal complex is normally utilized as a redox indicator.
• This redox indicator has a higher affinity for double-stranded DNA (dsDNA). This results
in a larger electrochemical response after hybridization.
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Highly sensitive glucose sensors based on enzymemodified whole-graphene solution-gated transistors
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graphene gate electrodes modified with an enzyme
glucose oxidase
Immunosensor (Silicon nanowire FET)
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Biomarker is defined as anything which could be used as an
indicator of a particular disease state.
Detection of specific biomarker can be applied to disease
screening; e.g, prostate specific antigen (PSA),
carcinoembryonic antigen (CEA) and Mucin 1
Biomarker usually exist in blood in low concentration, therefore
sensitive methods (nanobiosensors) are needed to detect those
antigen
Detection to Pg/ml
Help in early detection of cancer
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Other Applications
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Environmental field monitoring
Scientific crime detection
Food Analysis
Drug development
Summary and Conclusion
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An electrochemical biosensor characterizes the
analyte by measuring an electric signal generated
due to the reaction of that analyte with an
appropriate bioreceptor.
Two common ways for generating the electric signal
are amperometric and potentiometric techniques.
Nanotechnology fabrication can be utilized to
manufacture nanobiosensors, which have very high
sensitivity and can be applied in biomedical
diagnostic.
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References
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Youtube Lecture: nanoHUB-U Nanobiosensors L3.7: Sensitivity - Amperometric Sensors - Glucose
Sensors https://www.youtube.com/watch?v=FQfOyU06Cdw
M. Schoning and Arshak Poghossian, “Recent Advances in biologically sensitive field effect
transistors,” Analyst, vol. 127, 2002.
T. G. Drummond, M. Hill, and J. K. Barton, “Electrochemical DNA Sensors,” Nature Biotechnology,
2003.
K. Balasubramanian and M. Burghard, “Biosensors based on carbon nanotubes,” Anal Bioanal Chem,
vol. 385, pp. 452–468, 2006.
A. Chaubey and B. D. Malhorta, “Mediated Biosensors,” Biosensors and Bioelectronics, vol. 17, pp. 44456, 2002.
D. Grieshaber, R. MacKenzie, J. Voros, and E. Reimhult, “Electrochemical Biosensors – Sensor Principles
and Architectures,” Sensors, vol. 8, pp. 1400-1458, 2008.
W. Putzbach and N. J. Ronkainen, “Immobilization Techniques in the Fabrication of NanomaterialBased Electrochemical Biosensors: A Review,” Sensors, vol. 13, no. 4, pp. 4811-4840, 2013.
M. Zhang, C. Liao, C. Hin Mak, P. You, C. Mak & F. Yan “Highly sensitive glucose sensors based on
enzyme-modified whole-graphene solution-gated transistors” scientific reports, 2015
Kuan-I Chena, Bor-Ran Li, Yit-Tsong Chen, “Silicon nanowire field-effect transistor-based
biosensors for biomedical diagnosis and cellular recording investigation” nanotoday, 2011
Thanks for your attention
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Question?
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