MBC 414
BIOSENSOR
Introduction
A biosensor is a device that measures biological or chemical reactions by generating signals
proportional to the concentration of an analyte in the reaction. It is an analytical device, used for
the detection of a chemical substance, that combines a biological component with a
physicochemical detector. The sensitive biological element, e.g. tissue, microorganisms,
organelles, cell receptors, enzymes, antibodies, nucleic acids, etc., is a biologically derived
material or biomimetic component that interacts with, binds with, or recognizes the analyte under
study. The biologically sensitive elements can also be created by biological engineering.
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 (blood, urine, saliva, sweat). A typical biosensor consists of the Analyte,
bioreceptor, transducer, electronics, display.
, 1. Analyte: A substance of interest that needs detection. For instance, glucose is an ‘analyte’
in a biosensor designed to detect glucose.
2. Bioreceptor: A molecule that specifically recognises the analyte is known as a
bioreceptor. Enzymes, cells, aptamers, deoxyribonucleic acid (DNA) and antibodies are
some examples of bioreceptors. While the type of biomolecule used can vary widely,
biosensors can be classified according to common types of bioreceptor interactions
involving: antibody/antigen, enzymes/ligands, nucleic acids/DNA, cellular
structures/cells, or biomimetic materials. The process of signal generation (in the form of
light, heat, pH, charge or mass change, etc.) upon interaction of the bioreceptor with the
analyte is termed bio-recognition.
3. 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 signalisation. Most
transducers produce either optical or electrical signals that are usually proportional to the
amount of analyte–bioreceptor interactions. The most common types of biotransducers
used in biosensors are: electrochemical biosensors, optical biosensors, electronic
biosensors, piezoelectric biosensors, gravimetric biosensors, pyroelectric biosensors.
4. Electronics: This is the part of a biosensor that processes the transduced signal and
prepares it for display. It consists of complex electronic circuitry that performs signal
conditioning such as amplification and conversion of signals from analogue into the
digital form. The processed signals are then quantified by the display unit of the
biosensor.
5. 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. This part often consists of a combination of hardware and software that
generates results of the biosensor in a user-friendly manner. The output signal on the
display can be numeric, graphic, tabular or an image, depending on the requirements of
the end user.
BIOSENSOR
Introduction
A biosensor is a device that measures biological or chemical reactions by generating signals
proportional to the concentration of an analyte in the reaction. It is an analytical device, used for
the detection of a chemical substance, that combines a biological component with a
physicochemical detector. The sensitive biological element, e.g. tissue, microorganisms,
organelles, cell receptors, enzymes, antibodies, nucleic acids, etc., is a biologically derived
material or biomimetic component that interacts with, binds with, or recognizes the analyte under
study. The biologically sensitive elements can also be created by biological engineering.
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 (blood, urine, saliva, sweat). A typical biosensor consists of the Analyte,
bioreceptor, transducer, electronics, display.
, 1. Analyte: A substance of interest that needs detection. For instance, glucose is an ‘analyte’
in a biosensor designed to detect glucose.
2. Bioreceptor: A molecule that specifically recognises the analyte is known as a
bioreceptor. Enzymes, cells, aptamers, deoxyribonucleic acid (DNA) and antibodies are
some examples of bioreceptors. While the type of biomolecule used can vary widely,
biosensors can be classified according to common types of bioreceptor interactions
involving: antibody/antigen, enzymes/ligands, nucleic acids/DNA, cellular
structures/cells, or biomimetic materials. The process of signal generation (in the form of
light, heat, pH, charge or mass change, etc.) upon interaction of the bioreceptor with the
analyte is termed bio-recognition.
3. 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 signalisation. Most
transducers produce either optical or electrical signals that are usually proportional to the
amount of analyte–bioreceptor interactions. The most common types of biotransducers
used in biosensors are: electrochemical biosensors, optical biosensors, electronic
biosensors, piezoelectric biosensors, gravimetric biosensors, pyroelectric biosensors.
4. Electronics: This is the part of a biosensor that processes the transduced signal and
prepares it for display. It consists of complex electronic circuitry that performs signal
conditioning such as amplification and conversion of signals from analogue into the
digital form. The processed signals are then quantified by the display unit of the
biosensor.
5. 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. This part often consists of a combination of hardware and software that
generates results of the biosensor in a user-friendly manner. The output signal on the
display can be numeric, graphic, tabular or an image, depending on the requirements of
the end user.
