Lecture 6 - Biosensor

Question 0

Main Components of Biosensors

Answer 0

• biological recognition element or biochemical receptors
• transducer or detector element
• signal processing system

Question 1

Biosensor

• Definition
• Principle
• Mechanics

Answer 1

A small analytical device which utilize biological reaction for the detection of target analytes.

Utilizes immobilized biological sensing element and a transducer to produce an electrical signal proportional to the concentration of the substance to be measured.

Specific binding of the target analyte to the recognition element generates electrical signal (light, electronic current) that is detectable by a transducer ( CCD Camera, photodiode, electrode, nanostrucrure transistor)

Question 2

Examples of Biological Recognition Element

Hint:”MR ACEL aNd TOM”

Answer 2

Membrane 
Receptor 
Antibody 
Cells
Enzymes 
Lectin 
Nucleic acid
Tissues 
Organelles 
Microorganism

Question 3

Biological recognition element
-interaction
Hint:”NECA”

Answer 3

Nucleic acid and complementary sequence interaction
Enzymes and substrate interaction
Cellular interaction
Antibody and antigen interaction

Question 4

Transducer or Detector Elements

• definition
• classification

Answer 4

Converts bio recognition elements into measurable signals

Classifications:
Electrochemical measurement 
-electric 
-potential 
-resistive 
Mass Sensitive Measurement
-quarts crystal microbalance (QCM)
Optical Measurement 
-ethidium bromide 
-fluorescent 
-chemiluminesence
-fiber optic DNA sensor arrays 
Surface plasmon resonance

Question 5

Properties Required for Biosensor

Hint:”ALU MM PP RR 6S”

Answer 5

Accurate 
Low productivity cost
User friendly 
Marketable 
Minimal specimen 
Portable 
Precise
Rapid 
Reliable 
Simple
Small 
Specific 
Sensitive 
Safe 
Stable

Question 6

Applications of biosensors

Answer 6

Diagnostic
Monitor of food safety, freshness, and nutritional value
Detection of biological and warfare agents
Industrial analysis
Detections of environmental pollutant and pesticides

Question 7

Design of biosensors

Answer 7

Hand-held meters 
Bench-top models
Flow monitor devices
Implantable devices 
Bioaffinity devices 
Biocatalytic devices

Question 8

Electrochemical Biosensors
-types
Hint:”CPA”

Answer 8

Conductimetric

• determine conductance associated with change in ionic environment
• bioeletrical impedance analysis allows the determination of free-fat and total body water in subject without significant fluid and electrolytes abnormalities

Potentiometric

• electric potential measurement at constant measurement
• use ion selective electrodes to determine the changes in the concentration of chosen ions
• detect/monitor alcohol and glucose

Amperometric

• determine the electric current associated with electrons involved in redox processes
• detect/monitor ethanol, glucose, cholesterol,CF ^F508 deletion

Question 9

Other biosensors

Answer 9

Colorimetric Biosensors
-a.k.a thermal biosensors, thermometric biosensor

Whole microbial cell Biosensors

• cheaper
• longer active lifetime
• less sensitive to inhibition, pH, and temperature variations than enzymes.