title: Membrane fluidity measured by fluorescence polarization using an EPICS V cell sorter.
abstract: We have characterized the measurement of fluorescence polarization on single cells using an EPICS V cell sorter. A critical analysis is made of the balancing and calibration of the system. The system is highly linear for polarization measurements. Cellular membranes were labeled with 1,6-diphenyl-1,3,5-hexatriene (DPH) to measure membrane fluidity. Fluorescence polarization histograms had coefficients of variation as low as 7%. Cells labeled with DPH after 24 hr incubation in medium lacking serum showed a significantly higher fluorescence polarization than cells in medium containing serum. The fluorescence polarization measured at 15 degrees C was 0.311 compared to 0.270 at 25 degrees C for cells labeled with DPH, verifying that temperature affects the membrane fluidity as measured by flow cytometry.
mesh_terms: D000818:Animals; D002460:Cell Line; D002469:Cell Separation; D004161:Diphenylhexatriene; D005434:Flow Cytometry; D005454:Fluorescence Polarization; D006367:HeLa Cells; D006801:Humans; D008560:Membrane Fluidity
chemical_list: D004161:Diphenylhexatriene