BIOSENSOR AND IT’S

APPLICATION

By JOY KARMAKARDEPARTMENT OF INSTRUMENTATION SCIENCE JADAVPUR UNIVERSITY

A sensor is an object whose purpose is to detect events or changes in its environment, and then provide a corresponding output.

e.g Pressure sensor, Ultrasonic sensor , Humidity Sensor , Gas Sensor , Motion Sensor ,Biosensor , Acceleration sensor , Displacement sensor etc.

A transducer is a device that converts one

form of energy to another. e.g pressure sensor might detect pressure (a mechanical form of

energy) and convert it to electrical signal for display at a remote gauge.

A sensor is a type of transducer.

SENSOR & TRANSDUCER

Accuracy (how much accurate reading it produces) Precision (how close is the measured value to the true

value) Resolution ( smallest incremental change in the input

that will produce a detectable change in the output) Sensitivity (ratio of incremental output to incremental

input) Selectivity and specificity (depends on the unwanted

signals) Non linearity (deviation from linearity, i.e deviation from

best fit straight line obtained by regression analysis) Hysteresis

Sensor Characteristics

A biosensor is an analytical device, used for the detection of an analyte, that combines a biological component with

a physicochemical detector.

What is BIOSENSOR?

Professor Leland C Clark Jnr is known as the father of the biosensor . On 15 April 1956 the biosensor that he invented was named after him as “Clark electrode”(measured oxygen level in blood).

1975 Clark’s ideas became commercial reality with the successful re-launch of the Yellow Springs Instrument Company (Ohio) glucose analyser based on the amperometric detection of H2O2

1977 Karl Cammann introduced the term “biosensor”

HISTORY

(1918-2005)

SENSING ELEMENTSEnzymesEnzymes are proteins with high catalytic activity and selectivity towards substrates . They have been used for decades to assay the concentration of diverse analytes. Their commercial availability at high purity levels makes them very attractive for mass production of enzyme sensors. Enzymes have been immobilized at the surface of the transducer by adsorption, covalent attachment, entrapment in a gel or an electrochemically generated polymer, in bilipid membranes or in solution behind a selective membrane. Enzymes are commonly coupled to electrochemical and fiber optic transducers.

AntibodiesAntibodies are proteins that show outstanding selectivity. Molecules larger than about 10kDa can stimulate an immune response.Many antibodies are commercially available and commonly used in immunoassays. Antibodies are usually immobilized on the surface of the transducer by covalent attachment by conjugation of amino, carboxyl, aldehyde, or sulfhydryl groups. The surface of the transducer must be previously functionalized with an amino, carboxyl, hydroxyl, or other group.

MicrobesThe use of micro-organisms as biological elements in biosensors is based on the measurement of their metabolism. Microbial cells have the advantage of being cheaper than enzymes or antibodies,can be more stable, and can carry out several complex reactions involving enzymes and cofactors. Conversely, they are less selective than enzymes, they have longer response and recovery times, and may require more frequent calibration.

TRANSDUCING ELEMENTS Principle of detection

PIEZOELECTRIC Materials Quartz , Tourmaline, Rochelle salt , Lithium Sulphate , Barium Titanate

Shows piezoelectric effects i.e electric polarisation produced by mechanical strain in the crystal.

A piezoelectric disk generates a voltage when deformed (change in shape is greatly exaggerated)

AMPLIFIER

An amplifier, is an electronic device that increases the power of a signal Power amplifier Transistors

amplifier Operational

amplifier etc

OP-AMP

A/D CONVERTER

Counter controlled A/D converter

Successive approximation A/D converter

Flash/parallel A/D converter

Dual slope A/D converter

:4DIGIT 7 SEGMENT DISPLAY

APPLICATIONS Glucose monitoring , pregnancy test in diabetes patients ←historical

market driver

Environmental applications e.g. the detection of pesticides and river water contaminants such as heavy metal ions

Remote sensing of airborne bacteria e.g. in counter-bioterrorist activities Remote sensing of water quality in coastal waters by describing online

different aspects of clam ethology (biological rhythms, growth rates, spawning or death records) in groups of abandoned bivalves around the world

Determining levels of toxic substances before and after bioremediation Routine analytical measurement of folic acid, biotin, vitamin B12 and

pantothenic acid as an alternative to microbiological assay

Drug discovery and evaluation of biological activity of new compounds Detection of toxic metabolites such as mycotoxins

GLUCOSE MONITORING IN BLOOD

IN AGRICULTURE,FOOD INDUSTRY

DETECTION OF VIRAL FUNGAL BACTERIAL DISEASE OF PLANTS

DETECTION OF FOOD, TOTAL MICROBES IN SOFT DRINKS

DETERMINE FRESHNESS OF FRUIT,MEAT,FISH ETC.

OPTICAL BIOSENSOR USES CYANIDE TO GLOW BACTERIA AND DETECT IT

Tattoo biosensor warns when athletes are about to ‘hit the wall’

Disadvantages 1. Heat sterilization is not possible because of denaturaization of biological material, 2. Stability of biological material (such as enzyme, cell,

antibody, tissue, etc.), depends on the natural properties of the molecule that can be denaturalized under environmental conditions (pH, temperature or ions)

3. The cells in the biosensor can become intoxicated by

other molecules that are capable of diffusing through the membrane

4.Fabrication is Costly

CONCLUSIONWe can say that developing a biosensor is related with interdisciplinary study as Biology, Biochemistry, Chemistry, Electrochemistry, Physics, Kinetics and Mass transfer knowledge is required for this study. Proportional to the technological development and increase of interdisciplinary studies biosensors are being more useful and having more usage areas day by day. Recent development topics which are Electrochemical biosensor ,Fiber-optic biosensor Carbon Nanotube , Protein Engineering for biosensors Wireless Biosensors Networks So in near future the fabrication and use of Biosensors is going to be revolutionary.

BIBLIOGRAPHY• www.wikipedia.org• http://cdn.intechopen.com/pdfs/37345/InTech-Biosensor

s_and_their_principles.pdf• Sensors and Transducers book by D Patranabis• http://biosensor.se/• http://www.biosensors-congress.elsevier.com/• Fundamental prinples of Electronics by Dr B. Ghosh