Flow cytometry is a powerful technique that simultaneously measures and analyzes multiple physical characteristics of single particles, usually cells, as they flow in a fluid stream through a beam of light. Flow cytometry is widely used for analyzing expression of cell surface and intracellular molecules, characterizing and defining different cell types in heterogeneous cell populations, assessing the purity of isolated subpopulations, and analyzing cell size and volume. These characteristics are determined using an optical-to-electronic coupling system that records how the cell or particle scatters incident laser light and emits fluorescence (Figure 2).
Over the past 30 years, flow cytometry has become an indispensable tool for many scientific researchers and clinicians. The evolving technology ensures its application in a number of fields, including cell biology, drug discovery, cancer research, neuroscience, stem cell research, pathology, immunology, hematology, plant biology, food science and marine biology.