| Summary: | 碩士 === 國立中央大學 === 化學工程研究所 === 89 === This study investigated the behavior of mixed DMPC/PF-127 Gibbs’ adsorption monolayers (the weight ratio are 34: 4 , 34:14 and 34:34)and the PF-127 absorbed on different monolayers(the composition are DMPC, DMPC/Vit-E and DMPC/cholesterol)at the air/liquid interface at 25 . For mixed DMPC/PF-127 adsorption monolayers system at the air/water interface, the measurements of equilibrium surface tensions and surface pressure-area per molecule(Π-A) isotherms were carried out. The results of the mixed monolayer, the equilibrium surface tensions increased with the PF-127 concentration. But the excess of surface concentration is non- linear. TheΠ-A isotherms of the behavior of mixed DMPC/PF-127 monolayers indicate that the addition of the PF-127increased the shift percentages and the transition phases were obviously.
The behavior of the PF-127 adsorbed on different monolayers were investigated from the measurements of the change of surface pressure with time andΠ-A isotherms. In the PF-127 adsorption of monolayer systems, the equilibrium adsorption surface pressure increased with the PF-127 concentration and the initial surface pressure. The behavior of PF-127 adsorbed on DMPC/Vit-E and DMPC/cholesterol mixed monolayers, the ranges of equilibrium adsorption surface pressures are 15.8~28.3mN/m and 20.3~27.7mN/m, indicated that the addition of α-tocopherol and cholesterol change the distance of mixed monolayers. TheΠ-A isotherms of the PF-127 adsorbed to balance indicate that the transition phases were carried out and the PF-127 might be insert or absorb to monolayers. However, at higher surface pressure, the PF-127 molecules are squeezed into the subphase. From the DSC (differential Scanning Calorimetry ) experiments of liposome, the change of temperatures of phase transition regardless of the PF-127 incorporated or adsorbed to liposomes, which suggest the PF-127 does not insert or absorb deeply. Finally, the results obtained in this study support that the PF-127 can be readily absorbed or inserted onto liposome, providing steric barrier , preventing the fusion or aggregation of liposomes.
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