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Flow Cytometry Center

Services

The Flow Cytometry Center provides state of the art instrumentation and resources for fluorescent analysis of cells at the single cell level, including high-speed fluorescence-activated cell sorting. Our goal is to provide expertise in flow cytometry in the areas of experimental design, instrument knowledge and training, data analysis and cell sorting. We support the mission of NIEHS by providing the latest advances in flow cytometric technology to the institute for reducing the burden of diseases and dysfunctions associated with the environment.

Background

Flow cytometry is a powerful technique to simultaneously analyze multiple characteristics of thousands of individual cells in a relatively short period of time. Unlike other biochemical techniques, flow cytometry makes these multiparametric measurements on single cells as opposed to population measurements.

Cells stained with various fluorescent markers or dyes pass single file by a set of lasers where the cells of interest are specifically selected and sorted or isolated into individual tubes for further biochemical analysis
Animation of Flow Cytometer: Cells stained with various fluorescent markers or dyes pass single file by a set of lasers where the cells of interest are specifically selected and sorted or isolated into individual tubes for further biochemical analysis.

By definition, cytometry means cell measurement (Cyto = Cell; Metry = measurement). Flow cytometry measures many different characteristics of cells as they move in a stream and are excited by a light source (laser). As cells are exposed to the laser, they scatter light in different directions and emit fluorescence.

When scattered light is along the same axis as the laser light, it is detected in the forward scatter channel. Forward scatter tends to be more sensitive to surface properties of the cell, giving information about the cell size. Light scattered to the side or perpendicular to the axis the laser light is traveling is detected in the side scatter channel. Side scatter tends to be more sensitive to inclusions within the cell, giving information about the cell granularity.

In addition to scattered light, fluorescence signals are created when cells that have been exposed to a fluorescent molecule intercept the laser beam.

Many different types of fluorescent probes are commercially available. Some fluorescent probes interact directly with cellular components, such as fluorochromes that bind directly to DNA, RNA, or intracellular ions. There are also molecules that are attached to other probes, which provide specificity, such as fluorochromes attached to monoclonal antibodies or biological ligands. In some cases, a fluorescent molecule can be produced by the cell as a reporter, exemplified by the green fluorescent protein. Multiple probes with different excitation, which require more than one laser wavelength, or different emission wavelengths can be combined to provide multiparameter resolution for an individual sample. The molecules measured may be on the cell surface, in the cytoplasm, nucleus, or other intracellular organelle, depending on the specificity of the probe.

Flow cytometry also permits the physical isolation of various subpopulations of cells based on specific cellular characteristics by electrostatic separation. Four distinct populations of cells may be simultaneously sorted for a given sample. Cell sorting may be performed under sterile conditions, and various types of containers, such as eppendorf tubes or microscope slides, may be used to collect cells.

NIEHS Shared and Core Facilities are available to NIH researchers. Information for staff on utilizing these services may be found on the NIEHS Junction or by contacting the staff below.

Scientific Staff

Carl Bortner, Ph.D.
Carl D. Bortner, Ph.D.
Director, Flow Cytometry Center
P.O. Box 12233
Mail Drop F3-07
Durham, N.C. 27709

Tel 919-541-7535
Fax 301-480-2851
bortner@niehs.nih.gov
Marie Iannone
Marie A. Iannone, M.S.
Biologist
P.O. Box 12233
Mail Drop F3-07
Durham, N.C. 27709

Tel 919-541-3210
marie.iannone@nih.gov
Kevin Katen, M.S.
Kevin S. Katen, M.S.
Biologist
P.O. Box 12233
Mail Drop F3-07
Durham, N.C. 27709

Tel 919-316-4799
kevin.katen@nih.gov
Maria Sifre
Maria I. Sifre, M.S.
Biologist
P.O. Box 12233
Mail Drop F3-07
Durham, N.C. 27709

Tel 919-541-2165
Fax 919-541-1898
sifre@niehs.nih.gov