Basics of Flow Cytometry

Flow cytometry is a laser-based technology that is used to measure characteristics of biological particles. This technology is used to perform measurements on whole cells as well as prepared cellular constituents such as nuclei and organelles. Flow cytometers scan single particles or cells as they flow in a liquid medium past an excitation light source. The underlying principle of flow cytometry is that light is scattered and fluorescence is emitted as light from the excitation source strikes the moving particles. Light scattering and fluorescence is measured for each individual particle that passes the excitation source. Scattering and emission data can be used to examine a variety of biochemical, biophysical, and molecular aspects of particles. This unique and powerful technology is an important tool for many scientific disciplines because it allows characterization of cells or particles within a sample. Flow cytometry is particularly important for biological investigations because it allows qualitative and quantitative examination of whole cells and cellular constituents that have been labeled with a wide range of commercially available reagents, such as dyes and monoclonal antibodies.