Influences on Fluidity of Artificial Cell Membrane by Cholic Acid

The natural phospholipid DMPC and Ala, a kind of synthetic peptide lipid, were used to prepare artificial cell membrane vesicles. 10%, 20% and 30% cholic acid were added into the samples, re- spectively. DPH was taken as the fluorescence reagent and the influences on the fluidity of two kinds of vesicle samples were examined by fluorescence polarization technology. The results showed that in the setting temperature range, cholic acid of different concentrations had little ef- fect on the fluidity of DMPC vesicles. For Ala vesicles, in the temperature range of gel phase, pola- rization value decreased while the fluidity increased with the elevation of cholic acid concentra- tions. However, in the temperature range of liquid phase, cholic acid of different concentrations showed little effect. This research provides the theory basis on interaction mechanism of cholic acid and cell membrane in the natural organism.