Working and applications of biosensors in Pharmaceutical Industries
What is a biosensor?
A biosensor is a device, probe or electrode consisting of an immobilized biocatalyst (enzymes or cells).
A biosensor is an analytical device which is used to determine the presence and concentration of a specific substance in a biological analyte.
Uses of the biosensor device
- To detect microorganisms in water, food, etc and also for diagnostic purposes.
- Finding microorganisms in a blood sample or any biological sample to detect the disease or disorder.
- Used for detecting chemicals like antibiotics in a particular sample.
- Can be used to detect toxic chemicals in nutraceuticals or food supplements, packed food, etc.
- Can be used for detecting proteins (biomarkers). These proteins are present in the blood sample of a diseased person (e.g. Cancer patient) and hence disease can be diagnosed or detected.
- Early diagnosis of various diseases.
Composition of biosensor
Biosensor consists of immobilized enzymes or cells which are used in detection system
Bioreceptor
Different enzymes can be immobilized for different purposes like detection of various substances.
The substances which can be detected are as follows:
- Antibody, Nucleic acids
- Cells (microbial, plant, animal, human)
- MIP: macrophage inflammatory protein (protein)
Transducer
A transducer converts the interaction between the analyte (substance to be detected) and the immobilized enzymes and cells into a measurable signal.
The signal can be physical, chemical or electrical signal. Numbers of transducers are used which are listed as follows:
- Optical : absorption, fluorescence, interference
- Electrochemical : potentiometric, amperometric, conductimetric
- Mass based
- Temperature based
- Electric and magnet : dielectric and permeating properties, voltage or current.
Display unit
The signal is displayed onto the display unit of the biosensor.
Working of a biosensor
- Enzymes are a protein molecule which acts as a catalyst in several chemical reactions and are used as bioreceptors.
- The enzyme which is used in the biosensor reacts with the analyte or substances which is to be determined.
- The product formed is detected using a transducer and the signals which are produced are processed and converted into different measurable forms.
Examples of biosensors
There are several known biosensors, some of the examples are as follows
- For analyzing the quantity of alcohol, an enzyme alcohol oxidase is immobilized using glutaraldehyde where the transducer is oxygen.
- For determining glutamate concentration, glutamate decarboxylase is immobilized using glutaraldehyde having CO2 as the transducer.
- Urea uses polyacrylamide for immobilization of urease enzyme.
- Examples for glucose and penicillin are well discussed ahead.
Glucose biosensor
- Target molecule is glucose.
- For detection of glucose, glucose oxidase enzyme is used as bioreceptor.
- This enzyme is immobilized on a membrane.
- There is interaction between glucose and glucose oxidase enzyme which leads to formation gluconic acid.
- Transducer i.e. a signaling system is of electrochemical type, it detects the formation of gluconic acid based on its concentration. It converts formation of gluconic acid into electrochemical signal.
- Display unit, the electrochemical signal is measured by amperometer and the current is detected and converted into digital units.
Penicillinase biosensor
- It is used for detection of β-lactam antibiotics in a particular sample.
- Also used for determining/ detection of concentration of antibiotic.
DIFFERENCE BETWEEN ENZYME AND CELL IMMOBILIZATION
PROBABLE QUESTION’S ASKED:
- Explain the methods used in immobilization with suitable diagrams and examples.
- Write a note on biosensors.
- Explain in brief glucose oxidase or penicillinase as biosensors.
- Write the difference between all the immobilization techniques.
- Write a note on immobilization, ‘On’ a support.
- Write a note on immobilization, ‘In’ a support
Reference:
SIMPLIFIED CONCEPTS OF BIOTECHNOLOGY By, Dr. Pramod Kadu & Ms. Suchita Vishwakarma
Third Year B Pharm Notes, Syllabus, Books, PDF Subjectwise/Topicwise
Suggested readings:
