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National Flow Cytometry and Sorting Research Resource

Babetta L. Marrone, Ph.D.

Center Overview

The resource advances flow cytometric analyses through innovative research, development, and collaborations. Flow cytometry is a technique for high-speed analysis of individual particles ranging in size from single molecules and macromolecular complexes to subcellular organelles, cells, and cellular aggregates. Particles pass rapidly through one or more focused laser beams, where probe molecules bound to specific components, such as DNA in cells, are excited and the emitted fluorescence photons are detected. Measurement of fluorescence emissions and scattered excitation light provides quantitative information about the particles. For cells, measurements are made of DNA, RNA, and protein contents; surface molecules; internal antigens; and physiologic parameters. A wide variety of assay systems based on microspheres (generally 5-10 μm in diameter) are also available, including specific DNA/RNA binding, protein analysis, protein-protein and protein-nucleic acid interactions, and enzymatic activity. Because individual particles are analyzed, distributions of these and other measured parameters are obtained at analysis rates of thousands of events per second. On the basis of these measurements, particles in selected subpopulations can be physically separated by sorting. Unique flow cytometric capabilities in the resource include high-resolution chromosome analysis and sorting, fluorescence lifetime measurement, rapid-mix analyses with subsecond time resolution, phase-sensitive fluorescence detection, DNA fragment size quantification, ultrasensitive fluorescence detection, full spectral analysis, and a robust, flexible digital data display and analysis system. Expert advice and assistance are available to collaborators in the areas of cellular and chromosome sample preparation, multiplexed genetic and protein analysis, rapid kinetic analyses, macromolecular assembly dynamics, intrinsic property analysis, multivariate data acquisition and analysis, sorting procedures, and instrument development and troubleshooting.