DYNAMICS OF LABELLING CELL MEMBRANE WITH DPH AND THE CORRECTED DETERMINATION OF MEMBRANE FLUIDITY BY FLUORESCENCE POLARIZATION
DPH标记细胞膜的动力学与膜脂流动性的荧光偏振校正测量

The fluorescence polarization degree of fluorescence probe DPH labelled in cells was calculated from corrected fluorescence components measured by steady-state fluorescence technique.The plot of fluorescence polarization vs. labelling time was made and the fluorescence polarization of DPH located in cell membrane was obtained by extrapolating this curve to zero labelling time. In this way, the membrane fluidity of living Ehrlich ascite tumor cells was determined.Results show that the fluidity of cell membrane is less than that from whole cell determination,indicating that the order and the packing density of lipids are higher in cell membrane than in plasma.The experimental data fit well with that from three-compartment model analysis, it suggests that the fluorescence probe labelling process is mainly controlled by molecular diffusion.