Biosensor- device which uses a living organism or biological molecules, especially enzymes or antibodies, to detect the presence of chemicals.

1. NAME: SUVAGIYA DHRUVI
K.
CLASS: MSC. SEM 3
MICROBIOLOGY
TOPIC: BIOSENSOR
CLASSIFICATION

2. CLASSIFICATION OF
BIOSENSORS
 The pioneers named Clarke and Lyons began Biosensor in late 1960s.
Different kinds of biosensors being utilized based on two elements namely
known as sensing element and transduction modes.
 Enzymes based biosensor, immunosensor which includes antibodies, DNA
biosensor, Thermal and piezoelectric biosensor, biological tissues,
organelles and microorganisms which can be detected with the help of
whole cell biosensor comes under the category of sensing element.
 Transduction mode relies upon the physiochemical change coming about
because of detecting component.
 Subsequently on the premise of various transducers biosensors can be
electrochemical (amperometric, conductometric and potentiometric), optical
(absorbance, fluorescence and chemiluminense), piezoelectric (acoustic and
ultrasonic) And calorimetric.

3. CLASSIFICATION BASED ON
RECOGNISITION ELEMENTS
ENZYME
SENSOR
SPECIFIC
SUBSTRATE AS
RECEPTOR
IMMUNO
SENSOR
MONOCLONAL
ANTIBODIES AS
RECEPTOR
DNA
SENSOR
CELL
SENSOR
MICROBIAL
SENSOR

4.  Enzymatic Sensors These include pure enzyme preparations or biological
preparations (tissue or microbial culture homogenates) showing a certain
biological activity. The simplest enzymatic biosensor design is used when
the substrate or the product of the enzymatic reaction is electrochemically
active, capable of being rapidly and reversibly oxidized or reduced on an
electrode upon the application of an appropriate potential
 Immunosensors Immunoglobulins, which are protective proteins secreted by
the immune system of an organism in response to the ingress of alien
biological compounds (antigens), are employed in this case as the
biochemical receptor. Immunoglobulins, also known as antibodies, form
strong complexes with antigens.
 DNA Sensors The biochemical components of DNA sensors are nucleic
acids (DNA). Most frequently, they are not natural components isolated
from a living organism, but their fragments called DNA probes or DNA
primers. They are selected so that they reflect the specificity of the DNA
structure as a whole.
 Microbial Biosensors In most common microbial biosensors, the biological
component is separated from the recording device. This is due to the fact
that the response of microorganisms to variations in the chemical
composition of the medium is rather sluggish compared to the response of
enzymes or antibodies, because the former is mediated by matter transfer
across a biomembrane

5. CLASSIFICATION
BASED ON
TRANSDUCERS
PIEZO
ELECTRIC
ELECTRO
CHEMICAL
AMPERO
METRIC
POTENTIO
METRIC
CONDUCTO
METRIC
OPTICAL
COLORI
METRIC
PHOTO
METRIC
CALORI
METRIC
THERMI
STOR

6.  Electrochemical Transducers
Potentiometric transducers. The analytical signal in this case is the potential
drop between the working electrode and the reference electrode or between two
reference electrodes separated by a semipermeable membrane .
Voltammetric transducers. Here, the electroactive species oxidation or
reduction current is measured. The latter is induced by producing the preset
potential drop between the electrodes.
Conductometric transducers. These transducers measure the electrical
conductivity of the solution in the course of a biochemical reaction.
Impedimetric transducers. These devices measure the impedance of an
electrochemical cell and the variation of this impedance with ac frequency .
 Optical Transducers Optical transducers may be based on absorption,
fluorescence, luminescence, internal reflection, surface plasmon resonance,
or light scattering spectroscopy.
 Piezoelectric Devices Piezoelectric sensors employ crystals that undergo
elastic deformation under the action of an electric potential.
 Thermometric Transducers Measuring the amount of heat with a sensitive
thermistor provides means to determine the analyte concentration. Thermal
biosensors are quite uncommon