Everything you need to know about flow cytometry

Flow cytometry is a very effective technique used in biology and medicine to analyze and sort cells in suspension.

Two main approaches, conventional cytometry and spectral cytometry, are commonly used. Although their basic operation is similar, they differ in their analysis capabilities and specific applications.

The classic version

Conventional cytometry, also known as conventional flow cytometry, relies on the detection of light scattered and emitted by cells labelled with specific fluorochromes.

The cells are drawn into a continuous stream of buffer liquid and passed in front of a laser beam. The fluorochromes present on the cells react to laser excitation by emitting fluorescent light at specific wavelengths.

These fluorescent signals are detected by photomultipliers and converted into digital data for analysis.

The enhanced version

Spectral cytometry, on the other hand, extends the capabilities of conventional cytometry by enabling the detection and analysis of fluorescent light over a wider range of wavelengths.

Instead of using optical filters to separate the fluorescent signals, spectral cytometry uses a spectral dispersion system that divides the emitted light into its constituent wavelengths.

This enables more precise separation of superimposed fluorescent signals and offers better resolution of cell populations with multiple or complex labelling.

Compare before choosing

Conventional and spectral cytometry differ mainly in their ability to distinguish between fluorescent signals and analyze complex cell populations.

Spectral cytometry offers higher spectral resolution, allowing for a more accurate analysis of heterogeneous cell populations and providing samples with a strong superposition of fluorescent signals.

However, it generally requires more sophisticated equipment and more advanced analytical skills.

Author: Philippe St-Onge, Core Facilities’ Echo committee