Ethanol and Cholesterol Effects on Bilayer Characteristics of DPPC Liposomes

• Main Authors: Yu-LingHsieh, 謝佑翎
• Other Authors: Yu-Min Yang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/8t7q78

碩士 === 國立成功大學 === 化學工程學系 === 105 === The aim of this study was to investigate the effect of ethanol and cholesterol, respectively and simultaneously, on bilayer characteristics of DPPC liposomes. Stable liposomes were fabricated by using lipid with various amounts of ethanol and cholesterol in water through a forced formation approach, and the physical properties of vesicles were investigated by size, zeta potential and fluorescence polarization. In this work, fluorescence polarization was measured at different temperatures and typical sigmoidal thermograms could be observed. Experimental results revealed that the sizes of vesicles didn't show consistent trend, but zeta potential would decrease with addition of ethanol. Fluorescence polarization showed that addition of ethanol is likely to disorder part of the lipid headgroup region and decrease of phase transition temperature. Addition of cholesterol would increase the sizes and decrease zeta potentials of vesicles. However, as the liposomes also contained high concentration of ethanol, the effect of cholesterol was quite different and showed no consistent trend. Fluorescence polarization showed that the addition of cholesterol had no significant effect on phase transition temperature of lipid bilayers, but it would lead to disordering and condensing effect on vesicular bilayer rigidity at different phases. The opposite effect of cholesterol attributed to the formation of liquid ordered phase, and it could also be observed from liposomes with high concentration of ethanol.