Introduction to flow cytometry

How does flow cytometry work?

Flow cytometry is a technique used to analyze the properties of each cell in a sample population.

1.   First, a cell suspension solution flows through the chamber where it is then separated into a stream of single cells by the fluidics system.

2. The solution then passes through a laser beam or a set of lasers (Figure 1 – flow cytometry overview).

3.   A set of lenses, filters, and dichroic mirrors are used to collect and separate the light.

4. The light is collected at a 90-degree angle (side scatter – SSC) and directly opposite the cell flow (forward scatter – FSC).

5. The light is detected using photodiodes or photomultiplier tubes (PMTs).

Besides these inherent physical properties, fluorescence from markers can be assayed in a similar manner. Some flow cytometers can also sort cells based on the user gating conditions of these properties. This type of flow cytometry is often referred to as fluorescence-activated cell sorting (FACS).

Figure 1 - Flow Cytometry overview