GOVT. ARTS AND SCIENCE COLLEGE

RATLAM Topic : ENZYME BASED BIOSENSOR

Submitted to: Submitted by:Ms Kanushri Ranawat Shivangi Soni

Index• History • Introduction• Sensor• Principle• Components and working• Enzymes biosensor• Glucometer • Types of biosensor• Advantage and disadvantage • Reference

HistoryFirst commercial glucose biosensor was invented in 1975.

Introduction

It is an analytical device, used for the detection of analyt, that combine a biological component

with a physiochemical detector.

Sensor

- It is an analytical device which convert a biological response into an electric signal.

- It detects, records and transmit information regarding a physiological change or process.

Principle

1. Biological recognization element which is highly specific toward the biological analyt.

2. Transducer detect and traduce signal from biological target to electric signal which is due to reaction occur.

3. This electrical signal are amplified and can be read in detector after processing the value are display in

monitor.

Components and Working

Bioreceptor (biological)+Transducer (physiological)

Components:Bioreceptor (biological)

1.The component used to bind the target molecule.

2. This must be highly specific, stable under storage condition.

3. And immobilized on transducer.

Immobilization of receptorThe bioreceptor must immobilized on transducer by

following method.- physical adsorption- covalent binding -entrapment etc.

Transducer- It convert the bio recognization eventinto a

measurable signal.- This is done by measuring the change that occur in

the bioreceptor reaction.

Detector - Signal from the transducer are passed to a microprocessor where they are amplified and analyze.- The data is then converted and is display on monitor.

Ideal biosensor should be:

- highly specific for analyt.- device should be tiny and biocompatible.- device should be cheap and small.- easy to use.- should be durable.- capable of repeated use.- Should be sterilizable.- Should require small sample volume.

Enzyme based biosensor

- The biological material i.e. Enzyme is immobilized on transducer.- The analyte i.e. substrate binds to the enzyme to form a bound analyte.- The analyte is converted into a product which could be associated with the release of heat, gas, or hydrogen ions.- The transducer then convert the product linked change into electrical single which is amplified and measure.

Example of enzyme biosensorGlucometer

Procedure- A blood glucose meter is an electronic device for measuring the blood glucose level. - A relatively small drop of blood is placed on a disposable test strip which interfaces with a digital meter.- Within seconds, the level of blood glucose will be shown on the digital display.

How does it works?- Glucose react with glucose oxidase (GOD) to form gluconic acid.- Glucose mediator reacts with surrounding oxygen to form H2O2 (hydrogen peroxide).- higher the glucose content higher the O2 consumption.- glucose content can be detect by electrode.

3 different type of transducer can be use:

- an oxygen sensor that measure 02 concentration.- A pH sensor that measure the gluconic acid production.- A peroxide sensor that measure H2O2 concentration.

Types of biosensor

1. Calorimetric: measure changes in heat.

2. Optical: measure changes in light intensity.

3. Electrometric: detect changes in electrical conductivity.

4. piezoelectric: measure changes in mass.

5. potentiometric: measure changes in charge.

calorimetric biosensor

- these biosensor are also called thermometric biosensor or thermal biosensor.- Many enzyme catalyzed reaction produce heat (exothermic) - calorimetric biosensor measure the change in temperature of the solution containing the analyt.

Optical biosensor

- this biosensor measure the changes in fluorescence or in absorbance caused by the product generated by catalytic reaction.

Luciferin + ATP + O2 ---- oxyluciferin +CO2 + pyrophosphate + light

the above reaction happens in presence of enzyme Luciferase.

Potentiometric biosensor- These biosensor use ion selective electrode to convert the biological reaction into electronic signal.- The electrodes employed are most commonly pH meter glass electrodes.

CO(NH2)2 + 2H2O + H(+ion) -- 2NH4 (+ion) + HCO3 (-ion)

The above reaction happens in presence of enzyme urease.

Advantage 1. more specific than cell based sensor. 2. Faster responds due to shorter diffusion path (no cell walls).

Disadvantage1. More expensive to produce due to additional problem of isolating the enzyme.2. Enzyme are often unstable when isolated.

Example

Example

Example pregnancy test kit

Reference• B.D. Singh, Biotechnology ,Expanding Horizon .

Second edition, Chapter 15 , Enzymes Technology , Biosensor , Page 666-672.

• http://www.slideshare.net/951384/biosensors-33317356

• http://engineering.mit.edu/ask/how-do-glucometers-work

• https://en.wikipedia.org/wiki/Blood_glucose_monitoring#Blood_glucose_meters

• http://de.123rf.com/photo_9176220_diabetes-patienten-lustig-finger-glucose-level-bluttest-von-neuen-smart-glucometer-auf-weissem-hinte.html

THANK YOU