生物膜表面介电常数的荧光测量

FLUORESCENCE MEASUREMENT OF SURFACE DIELECTRIC CONSTANT OF CELL MEMBRANE

利用正交试验的方法,得到了荧光探针Dansyl Phosphatidyl-ethanolamine(DPE)标记艾氏腹水癌细胞质膜表面的最佳条件,首次建立了用DPE测定生物膜表面介电常数的方法.并用比方法测定了艾氏腹水癌细胞质膜表面介电常数,观察了有关的物理、化学因素对这种荧光测量方法的可能影响.

The measurement of surface dielectric constant (e) of cell membranes was carried out by determinating the wavelength of emission spectra maximum (λmax) of Dansyl Phosphatidylethanolamine (DPE), a fluorescent probe, labelled on cell membrane surface.By using the orthogonal method, the optimal conditions for labelling DPE on the membrane surface of mouse Ehrlich ascites cells were studied. Based on the determination of λmax of DPE in organic solvents with different dielectric constant and λmax of labelled DPE on membrane surface of mouse Ehrlich ascites cells, we measured the ε of native membranes (Ehrlich ascites cell membranes) to be 18.3±0.9 (n = 4). Inhibitors of respiration and glycolysis as well as uncouplers of energy transduction of mitochondria were found to have no effect on λmax of labelled DPE on liposomes. The change of incubation temperature could affect the fluorescence intensity of DPE but was unable to affect its λmax, indicating that the shift of λmax of DPE is related to the change of ε.