Takahara A, Takahashi K, Kajiyama T
Department of Chemical Science & Technology, Faculty of Engineering, Kyushu University, Fukuoka, Japan.
J Biomater Sci Polym Ed. 1993;5(3):183-96. doi: 10.1163/156856293x00285.
The relationships among surface, bulk properties and lipid sorption behaviors of segmented polyurethanes (SPUs) with various polyol soft segments were investigated. The polyols used in this study were poly(ethylene oxide) (PEO), poly(tetramethylene oxide) (PTMO), and poly(dimethylsiloxane) (PDMS). The hard segment of these segmented polyurethanes was composed of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol, present at 50 wt%. X-ray photoelectron spectroscopic (XPS) and dynamic contact angle measurements were carried out in order to analyze the surface chemical structure in the air- and water-equilibrated states. XPS revealed that in the air-equilibrated state, lower surface free energy components were enriched at the air-solid interface, whereas in the water-equilibrated state, higher surface free energy components were enriched at the water-solid interface. The change in environment from air to water induced the surface reorganization in order to minimize interfacial free energy. Lipid sorption behaviors of SPUs were investigated by means of infrared spectroscopy. Even after extensive rinsing of the surface, the amount of lipid present on the SPU surface was more than that calculated on the assumption that a monolayer covers the SPU surface. Therefore, the lipid was not only adsorbed on the surface of SPU but absorbed into SPU. The SPU with hydrophilic PEO sorbed larger amount of phospholipid compared with that with hydrophobic polyol such as PTMO and PDMS. Also, the competitive sorption behaviors of phospholipid and cholesterol from their mixed liposome solution were studied. The ratio of sorbed cholesterol to phospholipid increased with an increase in surface hydrophobicity owing to the hydrophobic nature of cholesterol.
研究了具有不同多元醇软段的嵌段聚氨酯（SPU）的表面性质、本体性质与脂质吸附行为之间的关系。本研究中使用的多元醇为聚环氧乙烷（PEO）、聚四氢呋喃（PTMO）和聚二甲基硅氧烷（PDMS）。这些嵌段聚氨酯的硬段由4,4'-二苯基甲烷二异氰酸酯和1,4-丁二醇组成，含量为50 wt%。进行了X射线光电子能谱（XPS）和动态接触角测量，以分析在空气和水平衡状态下的表面化学结构。XPS显示，在空气平衡状态下，较低表面自由能的组分在气-固界面富集；而在水平衡状态下，较高表面自由能的组分在水-固界面富集。从空气到水的环境变化引起了表面重组，以最小化界面自由能。通过红外光谱研究了SPU的脂质吸附行为。即使对表面进行了大量冲洗，SPU表面存在的脂质量仍超过假设单分子层覆盖SPU表面时计算出的量。因此，脂质不仅吸附在SPU表面，还被吸收到SPU中。与具有疏水性多元醇（如PTMO和PDMS）的SPU相比，具有亲水性PEO的SPU吸附了更多的磷脂。此外，还研究了磷脂和胆固醇从其混合脂质体溶液中的竞争吸附行为。由于胆固醇的疏水性，吸附的胆固醇与磷脂的比例随着表面疏水性的增加而增加。
