Stability and tribological performances of fluid phospholipid bilayers: Effect of buffer and ions
Stability and tribological performances of fluid phospholipid bilayers: Effect of buffer and ions
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DOI：
10.1016/j.colsurfb.2010.06.012
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发表时间：
2010-10-15
影响因子：
5.8
通讯作者：
Rieu, J. -P.
中科院分区：
文献类型：
--
作者：
Dekkiche, F.;Corneci, M. C.;Rieu, J. -P.
我们研究了支撑二油酰磷脂酰胆碱（DOPC）双层膜在不同溶液中的机械和摩擦学性能：超纯水（pH 5.5），盐溶液（150 mM NaCl，pH 5.8）。Tris缓冲液（pH 7.2）和Tris盐水缓冲液（150 mM NaCl，pH 7.2）。摩擦力的测量使用自制的生物摩擦计。在摩擦试验过程中，使用荧光显微镜原位控制脂质双层降解。压痕的机械阻力是通过原子力显微镜的力谱测量的。这项研究证实，在剪切或正常负载下的机械稳定性是必不可少的，以获得低和恒定的摩擦系数。在超纯水中，双层不具有抵抗力并且润滑性能较差。另一方面，在Tris盐水缓冲液中，它们完全抵抗压痕，并表现出低（mu = 0.035）和稳定的摩擦系数，在50分钟的摩擦测试期间没有可见的磨损。无缓冲盐溶液改善了压痕的机械阻力，但没有改善润滑性。这些结果表明，离子的吸附的两性离子双层膜的机械和摩擦学性能的双层：更高的阻力正常压痕由于增加双层的凝聚力，更高的润滑由于增加双层-双层排斥。(C)2010 Elsevier B. V.保留所有权利。
We have investigated the mechanical and tribological properties of supported Dioleoyl phosphatidylcholine (DOPC) bilayers in different solutions: ultrapure water (pH 5.5), saline solution (150 mM NaCl, pH 5.8). Tris buffer (pH 7.2) and Tris saline buffer (150 mM NaCl, pH 7.2). Friction forces are measured using a homemade biotribometer. Lipid bilayer degradation is controlled in situ during friction tests using fluorescence microscopy. Mechanical resistance to indentation is measured by force spectroscopy with an atomic force microscope. This study confirms that mechanical stability under shear or normal load is essential to obtain low and constant friction coefficients. In ultrapure water, bilayers are not resistant and have poor lubricant properties. On the other hand, in Tris saline buffer, they fully resist to indentation and exhibit low (mu = 0.035) and stable friction coefficient with no visible wear during the 50 min of the friction test. The unbuffered saline solution improves the mechanical resistance to indentation but not the lubrication. These results suggest that the adsorption of ions to the zwiterrionic bilayers has different effects on the mechanical and tribological properties of bilayers: higher resistance to normal indentation due to an increase in bilayer cohesion, higher lubrication due to an increase in bilayer-bilayer repulsion. (C) 2010 Elsevier B.V. All rights reserved.