Membrane fluidity measured by fluorescence polarization using an EPICS V cell sorter

Area of Science:

• Cell Biology
• Biophysics
• Analytical Chemistry

Background:

• Cellular membrane fluidity is a critical determinant of cell function.
• Accurate measurement of membrane fluidity is essential for understanding cellular processes.
• Flow cytometry offers a high-throughput method for single-cell analysis.

Purpose of the Study:

• To characterize the measurement of fluorescence polarization on single cells using an EPICS V cell sorter.
• To critically analyze the system's balancing and calibration for polarization measurements.
• To investigate the impact of environmental factors on cellular membrane fluidity.

Main Methods:

• Utilized an EPICS V cell sorter for fluorescence polarization measurements.
• Labeled cellular membranes with 1,6-diphenyl-1,3,5-hexatriene (DPH) to assess membrane fluidity.
• Analyzed fluorescence polarization histograms and assessed system linearity.

Main Results:

• The EPICS V system demonstrated high linearity for fluorescence polarization measurements.
• Fluorescence polarization histograms showed coefficients of variation as low as 7%.
• Cells incubated without serum exhibited significantly higher fluorescence polarization than those with serum.
• Membrane fluidity decreased with increasing temperature (0.311 at 15°C vs. 0.270 at 25°C).

Conclusions:

• The EPICS V cell sorter is a reliable tool for single-cell fluorescence polarization measurements.
• Serum presence and temperature significantly influence cellular membrane fluidity.
• Flow cytometry-based fluorescence polarization is a valuable technique for studying membrane dynamics.