Yamamoto Yasushi, Taga Keijiro, Yoshida Tadayoshi, Kamaya Hiroshi, Ueda Issaku
Department of Life and Materials Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
J Colloid Interface Sci. 2006 Jun 15;298(2):529-34. doi: 10.1016/j.jcis.2005.12.044. Epub 2006 Jan 18.
Interaction between phospholipid monolayers (dihexadecyl phosphate: DHP, dipalmitoyl phosphatidyl choline: DPPC) and water soluble ethanol has been studied using quartz crystal microbalance (QCM) method and quartz crystal impedance (QCI) method. The quartz crystal oscillator was attached horizontally on the DHP and DPPC monolayers that were formed on the water surface. At low concentration, increased ethanol concentration decreased the frequency for QCM and increased the resistance for QCI. Both frequency and resistance approached asymptotically to a saturation value. A further increase in ethanol concentration induced a sudden and discontinuous linear change (a decrease in frequency and an increase in resistance). Based on these results, we propose the following action mechanism of ethanol on phospholipid monolayers: at low concentration, the ethanol hydrates adsorb into the monolayer/water interface and saturate on the interface. The monolayer viscosity also increases with the adsorption of hydrates. A further increase in concentration causes multilayer formation of hydrates and/or penetration of hydrates into the monolayer core. The viscosity of the interfacial layer (monolayer and interfacial structured water) changes dramatically according to the action of ethanol hydrates.
利用石英晶体微天平（QCM）法和石英晶体阻抗（QCI）法研究了磷脂单层膜（磷酸二己酯：DHP，二棕榈酰磷脂酰胆碱：DPPC）与水溶性乙醇之间的相互作用。石英晶体振荡器水平附着在水面上形成的DHP和DPPC单层膜上。在低浓度下，乙醇浓度增加会使QCM的频率降低，使QCI的电阻增加。频率和电阻都渐近地接近饱和值。乙醇浓度的进一步增加会引起突然且不连续的线性变化（频率降低，电阻增加）。基于这些结果，我们提出乙醇对磷脂单层膜的以下作用机制：在低浓度下，乙醇水合物吸附到单层膜/水界面并在界面上饱和。单层膜的粘度也会随着水合物的吸附而增加。浓度的进一步增加会导致水合物形成多层结构和/或水合物渗透到单层膜核心。界面层（单层膜和界面结构化水）的粘度会根据乙醇水合物的作用而发生显著变化。
