15386_Biosensors and Biochips
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Transcript of 15386_Biosensors and Biochips
Basic Biosensor Instrumentation
A biosensor is made up of two parts:
1.Physical component: Transducer, amplifier, display unit, etc. 2.Biological component: Enzymes, antibodies, nucleic acids, etc.
Figure 6 Block diagram of a biosensor. Engineering Chemistry Copyright 2013 Wiley India Pvt. Ltd. All rights reserved.
Components of a Biosensor
Detector
Types of Biosensors
Based on the type of physical change produced, the biosensors are of following types:
1.Potentiometric biosensors: Measure the electrical potential. 2.Calorimetric biosensors: Measure the heat released or absorbed by a reaction. 3.Optical biosensors: Measure the light produced or absorbed during the reaction. 4.Acoustic wave biosensors: Measure the change in the mass of the biological material during the reaction. 5.Amperometric biosensors: Measure the movement of electron during an oxidation-reduction reaction.
Engineering Chemistry Copyright 2013 Wiley India Pvt. Ltd. All rights reserved.
RECOGNITIONHow do you specifically recognize the analyte?
Antibody DNA
Complementary DNA
Antigen Other:
enzyme/substrate
PNA/DNA or PNA/RNA
Antibody Antibody
Antibodies are biological molecules that exhibit very specific binding capabilities for specific structure (antigens).
Antigen It can be recognized by antibody.
Bioreceptors
membrane
Bioreceptors
Display
Bioreceptor
Enzyme is a large protein molecule that acts as a catalyst in chemical reactions. Enzymes are often chosen as bioreceptors based on their specific binding capabilities as well as their catalytic activity
Bioreceptors EnzymeEnzyme
Bioreceptors
Bioreceptor
Display
Four chemical bases:• adenine(A), guanine (G),
• cytosine (C), and thymine (T)
Bioreceptors
DNA structure Another biorecognition mechanism involves hybridization of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), which are the building blocks of genetics.
Bioreceptors
Bioreceptor
Display
Nourishment
Product
Bioreceptors
Living Cell Living Cell
Bioreceptors
Bioreceptor
Display
The immobilization is done either by physical entrapment or chemical attachment.
Immobilizatiom
Bioreceptor (Antibody, Enzyme, Cell, …) + polymer solution → polymerization
Physical Entrapment
adsorptive interactions such as ionic, polar or hydrogen bonding and hydrophobic interaction.
Adsorption
Example of biosensors
Pregnancy test Detects the hCG protein in urine.
Glucose monitoring device (for diabetes patients)
Monitors the glucose level in the blood.
Example of biosensorsExample of biosensors
Infectous disease biosensor
Old time coal miners’ biosensor