Overcoming rapid inactivation of lung surfactant: analogies between competitive adsorption and colloid stability.
Overcoming rapid inactivation of lung surfactant: analogies between competitive adsorption and colloid stability.
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克服肺表面活性剂的快速失活：竞争吸附和胶体稳定性之间的类比。
DOI：
10.1016/j.bbamem.2009.12.010
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Dhar,Prajna
中科院分区：
文献类型：
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作者：
Zasadzinski,JosephA;Stenger,PatrickC;Shieh,Ian;Dhar,Prajna
肺表面活性剂（LS）是脂质和蛋白质的混合物，排列在肺泡气液界面上，将界面张力降低到使呼吸成为可能的水平。在急性呼吸窘迫综合征（ARDS）中，LS 失活被认为在疾病的发展和严重程度中发挥着重要作用。本综述研究了 ARDS 患者肺泡液中 LS 和表面活性污染物（例如血清蛋白）的竞争吸附，以及这种竞争吸附如何导致正常量的正常 LS 无法有效降低界面张力。当 LS 和血清蛋白同时存在于肺泡液或朗缪尔槽溶液中时，它们会竞争空气-水界面。平衡有利于 LS，因为它具有较低的平衡表面压力，但较小的蛋白质在动力学上比多微米 LS 双层聚集体更有利，因为扩散速度更快。如果白蛋白到达界面，就会对随后的 LS 吸附产生能量势垒，从而减慢或阻止降低表面张力所需的必要量 LS 的吸附。这个过程可以根据经典的胶体稳定性理论来理解，其中扩散的能量势垒可以稳定胶体悬浮液以防止聚集。这种类比提供了关于表面活性剂失活起源的定性和定量预测。一个重要的推论是，任何促进胶体凝固的添加剂，如增加电解质浓度、多价离子、添加到LS中的亲水性非吸附性聚合物如PEG、葡聚糖等，或聚电解质如壳聚糖，也会在血清蛋白存在的情况下促进LS吸附，并有助于逆转表面活性剂失活。该理论提供了定量工具来确定这些添加剂的最佳浓度，并表明多种添加剂可能具有协同效应。包括等温线、荧光显微镜、电子显微镜和 X 射线衍射在内的各种物理和化学技术表明，通过这种机制增强了 LS 的吸附，而基本上不改变 LS 单层的结构或性质。
Lung surfactant (LS) is a mixture of lipids and proteins that line the alveolar air–liquid interface, lowering the interfacial tension to levels that make breathing possible. In acute respiratory distress syndrome (ARDS), inactivation of LS is believed to play an important role in the development and severity of the disease. This review examines the competitive adsorption of LS and surface-active contaminants, such as serum proteins, present in the alveolar fluids of ARDS patients, and how this competitive adsorption can cause normal amounts of otherwise normal LS to be ineffective in lowering the interfacial tension. LS and serum proteins compete for the air–water interface when both are present in solution either in the alveolar fluids or in a Langmuir trough. Equilibrium favors LS as it has the lower equilibrium surface pressure, but the smaller proteins are kinetically favored over multi-micron LS bilayer aggregates by faster diffusion. If albumin reaches the interface, it creates an energy barrier to subsequent LS adsorption that slows or prevents the adsorption of the necessary amounts of LS required to lower surface tension. This process can be understood in terms of classic colloid stability theory in which an energy barrier to diffusion stabilizes colloidal suspensions against aggregation. This analogy provides qualitative and quantitative predictions regarding the origin of surfactant inactivation. An important corollary is that any additive that promotes colloid coagulation, such as increased electrolyte concentration, multivalent ions, hydrophilic non-adsorbing polymers such as PEG, dextran, etc. added to LS, or polyelectrolytes such as chitosan, also promotes LS adsorption in the presence of serum proteins and helps reverse surfactant inactivation. The theory provides quantitative tools to determine the optimal concentration of these additives and suggests that multiple additives may have a synergistic effect. A variety of physical and chemical techniques including isotherms, fluorescence microscopy, electron microscopy and X-ray diffraction show that LS adsorption is enhanced by this mechanism without substantially altering the structure or properties of the LS monolayer.