Flow Cytometry Made Simple: From Cells to Signals

Flow cytometry is a laboratory technique used to analyze the physical and chemical characteristics of particles suspended in a fluid (such as cells, bacteria, or chromosomes).

Cells pass one by one through a laser beam, where light scattering and fluorescence are measured to determine:

• Cell size
• Internal complexity
• Specific cellular markers
  

 Basic Principle

Cells in suspension are aligned in a single-file stream and passed through a laser. The interaction between light and cells generates signals that are detected and analyzed.

 Core Components of Flow Cytometry

1. Fluidic System

• Transports cells in a single stream 
• Uses pressurized sheath fluid
• Ensures cells pass one at a time 
  

2. Optical System

• Lasers to excite cells/fluorophores
• Filters & detectors to capture scattered and emitted light
  

3. Electronic System

• Converts optical signals into electrical signals 
• Processes them into digital data for analysis 
  

Key Measurements

1. Forward Scatter (FSC)

• Indicates cell size 
  

2. Side Scatter (SSC)

• Indicates internal complexity/granularity 
  

3. Fluorescence Intensity

• Measures specific markers using fluorescent dyes or antibodies
  

Applications

1. Diagnostics

• Detection of leukemia, lymphoma, and immune disorders
  

2. Immunophenotyping

• Identification of specific immune cell populations 
  

3. Fluorescence-Activated Cell Sorting (FACS)

• Sorting of cells based on specific characteristics 
  

4. Cell Cycle Analysis

• Determines DNA content and cell cycle stage