Role of enzymes in biosensor

Presented by:

Waqar-un-nisa

Humaira anwar

Nadia bashir

Nazia sharif

Presented to:

Dr. Samar khan

ROLE OF ENZYMES IN BIOSENSOR

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 the concentration or activity of analyte present in the sample

Components of biosensor

Biologically active material or biological recognition element.

Detector element or transducer.

Signal processor.

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.

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.

Types of biosensor

Biosensor is broadly classified into two classes:I) On the basis of biological element

a) Enzyme Biosensorb) Microbial Biosensorc) Antibody Based.

II) On the basis of transducing element

a)Electrochemical transducers: The two common types of electrochemical transducers are:

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.

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

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.

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.

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.

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.

APPLICATION OF ENZYMES BASED

BIOSENSORS

ANY QUESTION?