PHASE-FIELD SIMULATIONS OF THE MORPHOLOGICAL EVOLUTION OF LIPID BILAYER MEMBRAN

脂质双层膜形态演化的相场模拟

• 批准号: 8171925
• 负责人: KAREN A THORNTON
• 金额: $ 0.14万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8171925
• 关键词: Affect; Biological; Biosensor; Cell Adhesion; Cell membrane; Cell physiology; Cells; Cholesterol; Computer Retrieval of Information on Scientific Projects Database; Coupled; Coupling; Drug Delivery Systems; Endocytosis; Equation; Equilibrium; Evolution; Free Energy; Funding; Grant; Hydrophobic Interactions; Immunologist; Individual; Infection; Institution; Investigation; Lipid Bilayers; Lipid Binding; Lipids; Liquid substance; Mammalian Cell; Membrane; Membrane Microdomains; Methods; Modeling; Phase; Process; Proteins; Regulation; Relaxation; Research; Research Personnel; Resources; Shapes; Signaling Protein; Simulate; Source; Structure; System; United States National Institutes of Health; Vesicle; pathogen; saturated fat; simulation

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Biological membranes are structures composed of multiple lipid species and proteins. The lipids are bound only through hydrophobic interactions, creating a liquid-like structure. The plasma membrane, a lipid bilayer membrane surrounding all mammalian cells, is not homogeneous, but rather contains domains termed rafts, defined as regions enriched with cholesterol and saturated lipids. Understanding how and why these rafts form is of great importance to cell biologists and immunologists, since they are involved in many important cell functions and processes including endocytosis, cell adhesion, signaling, protein organization, lipid regulation, and infection by pathogens. These raft structures also show great potential for technological applications, especially in connection with biosensors and drug delivery systems. We examine phase separation (lipid raft formation) and morphological evolution of multicomponent lipid bilayer membranes. The model applies to membranes with planar and spherical background geometries, simulating a nearly planar portion of a membrane or an entire vesicle, respectively. The model treats the individual composition of each bilayer leaflet, which determines the spontaneous curvature. The compositions and shape of the membrane are coupled with a modified Helfrich free energy, which includes coupling between the leaflets compositions. The compositional evolution is modeled using a phase-field method and is described by a Cahn-Hilliard-type equation, while the shape changes are described by relaxation dynamics. For nearly planar bilayer systems we construct a phase diagram of equilibrium morphological phases in the composition space for a few values of the strength of the leaflet coupling. For vesicles modeled using a spherical background, our investigations have focused on how the dynamics are affected by spontaneous curvature effects.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 生物膜是由多种脂质和蛋白质组成的结构。脂质仅通过疏水相互作用结合，产生液体状结构。质膜是包围所有哺乳动物细胞的脂质双层膜，它不是均匀的，而是包含称为筏的结构域，筏被定义为富含胆固醇和饱和脂质的区域。了解这些木筏如何以及为何形成对于细胞生物学家和免疫学家来说非常重要，因为它们参与许多重要的细胞功能和过程，包括内吞作用、细胞粘附、信号传导、蛋白质组织、脂质调节和病原体感染。这些筏结构也显示出巨大的技术应用潜力，特别是在生物传感器和药物输送系统方面。我们研究相分离（脂筏形成）和形态演变的多组分脂质双层膜。该模型适用于膜与平面和球形的背景几何形状，模拟一个膜或整个囊泡，分别接近平面的一部分。该模型处理每个双层小叶的个体组成，其决定自发曲率。膜的组成和形状与修改的Helfrich自由能耦合，其包括小叶组成之间的耦合。成分的演变是使用相场法建模，并描述了一个Cahn-Hilliard型方程，而形状的变化是由弛豫动力学描述。对于近平面的双层系统，我们构建了一个相图的平衡形态相在组合物空间的小叶耦合的强度的几个值。对于使用球形背景建模的囊泡，我们的调查集中在如何动态自发曲率效应的影响。