ABSTRACT
Flow cytometry (Flow = motion, Cyto = cell, Metry = measurement) is high throughput technology that allows the measurement and analysis of physical, chemical, and biological properties of individual cells or cell-like particles within homogenous or heterogeneous populations while they are flowing in a single file at high speed. Since its inception and commercialization more than 50 years ago, the technology of flow cytometry has advanced by leaps and bounds and continues to make a significant impact in biological research. Fluorescence-based flow cytometry affords multi-parametric, rapid and high-throughput analysis of stained single cells in suspension. The fluidic systems in the flow cytometers employ hydrodynamic (and in some cases hydrodynamic and acoustic) focusing to ensure that cells pass the light sources in a single file. Flow cytometers typically utilize LASERs as light sources to generate scatter and fluorescent light signals from the cells that are acquired by detectors (photodiodes/photomultiplier tubes/avalanche photodiodes). These signals are amplified and converted into electronic signals that are coded in a standard format as a .fcs (flow cytometry standard) data file. Cell populations can be analyzed and/or sorted out by utilizing the relevant fluorescent and light-scattering profile of individual cells. Flow cytometry has diverse applications in almost all the fields of biology, such as cell biology, immunology, molecular biology, bacteriology, virology, environmental science, clinical diagnostics, etc. The objective of this chapter is to introduce this powerful tool and its various applications.
