Thermodynamics of monolayers formed by mixtures of phosphatidylcholine/phosphatidylserine.
Thermodynamics of monolayers formed by mixtures of phosphatidylcholine/phosphatidylserine.
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由磷脂酰胆碱/磷脂酰丝氨酸混合物形成的单层的热力学。
DOI：
10.1016/j.colsurfb.2011.02.037
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Aranda-Espinoza,Helim
中科院分区：
文献类型：
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作者：
Luna,Carlos;Stroka,KimberlyM;Bermudez,Harry;Aranda-Espinoza,Helim
在这项工作中，我们获得了混合的（1-硬脂酰-2-油酰-sn-甘油-3-磷酸胆碱）PC和（1-硬脂酰-2-油酰-sn-甘油-3-磷酸-l-丝氨酸（钠盐））PS单层的热力学性质。压缩性（等温线、体积模量和每个分子的过剩面积）和表面电势的测量表明，空气-水界面处单分子层的性质取决于离子（Na+和K+）的浓度以及混合物中PS的比例。对 PS 的依赖性是因为该分子最初与 Na+ 抗衡离子结合；通过增加离子浓度，熵会发生变化，为结合的 PS 反离子加入主体创造一个有利的系统，留下带负电的分子。这种变化导致静电斥力的增加，这反映在每个分子面积相对于表面压力的增加和更高的表面电势。结果得出这样的结论：这种磷脂混合物遵循非理想行为，可以帮助理解由两性离子和阴离子磷脂与结合抗衡离子的二元混合物制成的膜的热力学行为。
In this work we obtain the thermodynamic properties of mixed (1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine) PC and (1-stearoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (sodium salt)) PS monolayers. Measurements of compressibility (isotherms, bulk modulus, and excess area per molecule) and surface potential show that the properties of monolayers at the air–water interface depend on the concentration of ions (Na+and K+) and the proportion of PS in the mixture. The dependence on PS arises because the molecule is originally bound to a Na+counterion; by increasing the concentration of ions the entropy changes, creating a favorable system for the bound counterions of PS to join the bulk, leaving a negatively charged molecule. This change leads to an increase in electrostatic repulsions which is reflected by the increase in area per molecule versus surface pressure and a higher surface potential. The results lead to the conclusion that this mixture of phospholipids follows a non ideal behavior and can help to understand the thermodynamic behavior of membranes made of binary mixtures of a zwitterionic and an anionic phospholipid with a bound counterion.