BILL TELFORD, Ph.D., National Cancer Institute, National Institutes of Health (NIH)
Flow cytometry was first patented in 1953, but it became an effective method for the analysis of large numbers of biological cells with the introduction of lasers. Simple flow cytometers shine the beam of a single laser onto a rapidly flowing jet of particles. By the fluorescence (or scattered) radiation, the machine can recognize certain spectral features and thus distinguish or even actively sort single cells.
As described by Bill Telford, a scientist at the Flow Cytometry Research Laboratory of the National Cancer Institute, from genetics to pathology, flow cytometry has proved to be an efficient technology throughout almost all fields of medicine and life sciences. With hundreds of different fluorescent markers available, one can label almost every protein in or on a cell. Detecting receptors, pumps, or nuclear proteins allows researchers to identify and trace every part of a cell.
Modern flow cytometers use several lasers and can track many labels simultaneously. Small systems with one or two lasers follow 2–4 fluorescent parameters for simple analytical tasks like cell viability. Clinical flow cytometers can analyze 4–10 fluorescent parameters, and research systems analyze up to 30 fluorescent parameters simultaneously.
Telford said that in the future, more wavelengths in the UV and IR are expected. New imaging techniques will be added to next-generation flow cytometers and full-spectrum analysis will become viable. Microfluidic-based cell sorters are now available, although they are still slower than their electrostatic ancestors.
