Fluorescence activated cell sorter FACS

A fluorescence-activated cell sorter (FACS) is a flow cytometry instrument used to separate and identify cells in a heterogeneous population. Cell mixtures to be sorted are first bound to fluorescent dyes such as fluorescein or phycoerythrin. The labeled cells are then pumped through the instrument and are excited by a laser beam. Cells that fluoresce are detected, and an electrostatic charge is applied. The charged cells are separated using voltage deflection. 

Fluorescence-activated cell sorters (FACS) have been used to separate subpopulations of cells for subsequent treatment or analysis (see Chapter 30). However, this approach requires that the cells be in suspension. In the case of adherent cells, some cannot be easily suspended, or the treatments used to suspend them may interfere with subsequent analysis. In these situations, a laser microheam system capable of fluorescence imaging can serve two purposes. At low power, the laser can excite fluorescence to produce an image, and at a higher power, the laser can be used to kill the undesired cells. 

Newer strategies for stem cell identification have been developed based on the knowledge of cell functions. A primitive and multipotential subpopulation of bone marrow mononuclear cells has been identified on the basis of the intracellular presence of aldehyde dehydrogenase (ALDH). Those cells can be marked on the basis of the presence of ALDH and are called aldehyde dehydrogenase-bright cells (ALDH cells), allowing for their separation from a bone marrow aspiration mononuclear subpopulation under fluorescence-activated cell sorter (FACS) analysis. 

Fluorescence-activated cell sorter (FACS) To predict and select cells in the population that express target protein Sensitive and allows direct sorting and cloning of positive cells Required proteins expressed intracellnlarly or on the cell snrface. Not sensitive for expression system engineered to secrete the protein... 

Parks, D. R., Bryan, V M., Oi, V. I, and Herzenberg, L. A (1979) Antigen-specific identification and cloning of hybridomas with a fluorescent-activated cell sorter (FACS) Proc Natl Acad Sci USA 76, 1962-1966... 

Fluorescence-activated cell sorter (FACS), e.g., Becton Dickinson FACScan (see Chapters 33 and 34). 

A third aspect of flow cytometry (known sometimes simply with the acronym for fluorescence-activated cell sorter, FACS, or even more familiarly as just flow) that distinguishes it from many other techniques is the way in which its wide and increasing usefulness has continued to surprise even those who consider themselves experts. What began as a clever technique for looking at a very limited range of problems is now being used in universities, in hospitals, within industry, at marine stations, on submersible buoys, and on board ships plans have existed for use on board space ships as well. The applications of flow cytometry have proliferated (and continue to proliferate) rapidly both in the direction of theoretical science, with... 

Fluorescence-Activated Cell Sorter (FACS) Analyses... 

A flow cytometer identifies different cells by measuring the light that they scatter and the fluorescence that they emit as they flow through a laser beam thus it can sort out cells of a particular type from a mixture. Indeed, a fluorescence-activated cell sorter (FACS), an instrument based on flow cytometry, can select one cell from thousands of other cells (Figure 5-34). For example, if an antibody specific to a certain cell-surface molecule is linked to a fluorescent dye, any... 

Flow c rt ometiy can Identify different cells on the basis of the light that they scatter and the fluorescence that they emit. The fluorescence-activated cell sorter (FACS) Is useful In separating different types of cells (see Figures 5-34 and 5-35). 

Microfluidic device can be used to sort cells. Fluorescence-activated cell sorter (FACS) machines have been scaled down to chip size. Single cell manipulation at a high speed is made possible by the fast response time of an integrated piezoelectric (PZT) actuator. Cells are sorted on the detected optically expression [46]. Cells can also be separated in an electric held on the basis of electrically distinguishable phenotypes [47]. Other cell sorters look at the fitness of the cell. For example, semen can be fractionated by their ability to swim through interfaces between adjacent laminar streams into separate streamlines, which enables isolation of motile, morphologically normal spermatozoa from semen samples [48]. This resulted in a microscale sperm sorter in which high-quality sperm can be isolated and used for in vitro fertilization [49]. 

Fig. 3 B-cell recovery and SPD in all responders (pivotal trial). Median B-cell counts in peripheral blood (as measured by CD 9 positivity on Fluorescence Activated Cell Sorter (FACS) analysis) drop to zero and start recovering by the sixth month. Tumor volume (as measured by SPD) for responders continues to decrease beyond nine months despite normalization of B-cell counts [38, 39]. This figure is used by permission from the copyright holders - Grillo-Lopez A] and Idee Pharmaceuticals.

Daunorubicin and rhodaminel23 (P-gp substrates), Calcein (a MRP substrate) (Sarkadi et al., 2001), LysoTracker (Xia et al., 2005b) (a BCRP substrate), and H2FDA and BODIPY (BSEP substrates) have been used as fluorescent substrates for the screening of transporter inhibitors and their concentrations can be measured by fluorescence-activated cell sorter (FACS) flow cytometry (Wang et ah, 2000, 2003) or any fluorescence detectors. 

In addition to the above-mentioned experiments using PS-based nanoparticles, the hydrophobic fluorescent dye A-(2,6-diisopropylphenyl)perylene-3,4-dicarbonacidimide (PMI) could also be successfully incorporated in phosphate-functionalized poly(methylmethacrylate) (PMMA) and PS [33], polyisoprene (PI), PS-co-PI [34], PBCA [35, 36] and polylactide (PLLA), or poly(e-caprolactone) (PCL) nanoparticles [37] in order to study the cellular response to these polymeric nanoparticles. For qualitative investigations, confocal microscopy can be used the quantitative measurements can be realized by a fluorescent activated cell sorter (FACS). 

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