Flow Cytometry: The Use of Lasers for Rapid Analysis and Separation of Single Biological Cells

The term flow cytometry describes a relatively new technique for making rapid measurements on individual biological cells as they pass in single file through a laser beam. The early history of this rapidly expanding technology has been reviewed by Mullaney et al. (1976). The development of the argon-ion laser enabled precise measurement of cellular DNA content, using fluorescent stains which bind stoichiometrically to DNA. The technology has since expanded to include flow cytometer instruments for (1) studies of doubly stained cells by means of multiple lasers and fluorescence detectors, (2) single chromosome analysis, (3) measurements of scattered light with multiple detectors, (4) studies of polarized fluorescence emission from single cells, and (5) scanning and imaging of cells as they pass through a laser beam. The present review surveys some of the laser-related instrumentation developments in this subfield of automated cytology and indicates some new directions for growth in this research area.