At the interrogation point, where the blue laser hits the red cells in the graphic, the cells pass through a laser beam or beams that excite florescent probes bound to selected cellular targets, emitting light of a different color for each unique probe. The fluidics system accepts the cell sample (colored red dots in this illustration) and transports it to the interrogation point, while forcing the cells into a single file stream though either hydrodynamic or acoustic focusing. Cytometers are generally comprised of fluidics, optics, and electronics systems.
Cytometers, with a few examples shown here, come in all shapes and sizes but they share some underlying principles. The tool used to make these measurements is called a cytometer. Single cell data can be collected using flow cytometry: the measurement of cells in a flowing medium. Welcome to FlowJo University! Before we begin the discussion on how to use FlowJo to analyze single cell data, lets first discuss where that data comes from.
