Biosensors Overview and Applications

Study Notes

A biosensor is an analytical device that detects an analyte by combining a biological component with a physicochemical detector component.
Biosensors have three parts:
- Biological recognition elements: These components differentiate target molecules.
- Transducer: This converts a biorecognition event into a measurable signal.
- Signal processing system: This converts the signal into a readable format.
Examples of biological elements include:
- Enzymes
- Cells
- Microorganisms
- Antibodies
- Nucleic acids

Biosensors are used in various disciplines:
- Medicine
- Food industry
- Environmental science
Biosensors now play a role in:
- Detecting analytes.
- Measuring concentrations of substances.

Catalytic biosensors: Uses enzymes as the biological component
- Commonly used enzyme is glucose oxidase.
- Converts glucose to gluconic acid while consuming oxygen, detected electrochemically.
- Urease can help break down urea to ammonia and carbon dioxide.
Tissue-based biosensors: Simple designs, often using natural biological materials
- Examples include biosensors made from a banana to detect dopamine.
Microorganism-based biosensors:
- Combines microorganisms with a transducer.
- Enables rapid, accurate, and sensitive detection of target analytes across many fields, including medicine, environmental monitoring, defense, food processing and safety.
Antibody-based biosensors (immune-sensors):
- Organisms produce antibodies that bind to specific antigens.
- Provide high selection specificity and sensitivity.

High sensitivity.
Simple calibration with standard materials, such as solutions in known quantities.
Linear response.
Minimal background signal noise with the ability to correct.
No hysteresis.
Selectivity.
Long-term stability.
Dynamic response.
Biocompatibility.