1. Role of enzymes in biosensor
Presented by:
Waqar-un-nisa
Humaira anwar
Nadia bashir
Nazia sharif
Presented to:
Dr. Samar khan

2. ROLE OF ENZYMES IN BIOSENSOR

3. Introduction
 What is biosensor?
 The term “ biosensor ” was introduced By Clark and Lyos in
1962.
 Biosensor is a device which involves incorporation of bioactive
material with transducing element for detecting
concentration or activity of analyte present in the sample
the

4. Components of biosensor
 Biologically active material or biological recognition
element.
 Detector element or transducer.
 Signal processor.

6. Principle of biosensor
Immobilization
of
biological
material
on
the
immobilization support, the permeable membrane, in the
direct vicinity of a sensor.
The substances to be measured pass through the
membrane and interact with the immobilized material and
yield the product.

7.  The product passes through another membrane to the
transducer.
 The transducer converts product into an electric signal which is
amplified.
 The signal processing equipment converts the amplified
signals into a display most commonly the electric signal which
can be read out and recorded.

10. Types of biosensor
 Biosensor is broadly classified into two classes:
 I) On the basis of biological element
 a) Enzyme Biosensor
 b) Microbial Biosensor
 c) Antibody Based.

11. II) On the basis of transducing element
 a)Electrochemical
transducers:
electrochemical transducers are:
The
two
common
types
of
 Amperometric and Potentiometric transducer.
 Amperometric transducers measure the potential between the two
electrodes is set and current produced by oxidation –reduction of electro
active species is measured and correlated with the concentration of the
analyte of the interest.

12.  Potentiometric measures the potential of electrochemical cell
with very low current value.
 b) Optical Transducer: They are used for determining the
concentration of analyte on the basis of change in optical
density at appropriate wavelength. I.e. Total Internal Reflection
is measured with a Photodetector as a function of incident
angle.
 c) Calorimetric Transducers: It is used for calculating the
heat of biochemical reactions by measuring the temperature
difference between the reaction vessel and isothermal heat sink
surrounding

13. The advantages of employing enzymes in biosensor
architecture
 Enzymes have a high selectivity for their substrates.
 They exhibit a very high catalytic activity.
 An
enzyme-based electrochemical sensor is formulated by
immobilizing a thin layer of enzyme on the surface of the membrane of
an electrode. The analyte to be monitored diffuses into the enzyme
layer where the catalytic reaction occurs, either consuming a substrate
or generating a product that can be detected electrochemically.

14.  Enzyme Biosensor: Enzyme because of its high
selectivity and activity towards substrate are the best
candidate to be used as biologically active materials.
 Enzymatic
biosensors measure the selective
inhibition or the catalysis of enzymes by a specific
target. Most of the enzymes used in biosensor are
Oxidizes but there are certain limitations as their
activity is susceptible to pH, temperature, ionic
strength etc.

16.  Enzyme-based biosensors represent a major application of
immobilized enzymes in medicine.
 The high specificity and reactivity of an enzyme towards
its substrate are properties being exploited in biosensor
technology.

17.  Enzymes that are used in biosensors often belong to the
classes of oxidoreductases and hydrolases.
 Thus, they are particularly suitable for their coupling with
electrochemical transducers.

18. APPLICATION OF ENZYMES BASED
BIOSENSORS