Adhesion Deformation and Fusion of Bilayer Vesicles and Other Amphiphilic Structures in Solution

溶液中双层囊泡和其他两亲结构的粘附变形和融合

• 批准号: 8721741
• 负责人: Jacob Israelachvili
• 金额: $ 18万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-01 至 1990-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8721741&HistoricalAwards=false
• 关键词: Adhesion; Deformation; Fusion; Bilayer; Vesicles

Forces between amphiphilic structures such as bilayers, vesicles, microemulsion droplets and biological membranes are accompanied by elastic deformation of the structures as they approach and come into contact. These deformations are dependent on both the inter-aggregate and intra-aggregate forces and their coupling. This project is a study of the adhesion, fusion and accompanying structure deformations using direct force measurements, freeze-fracture, and in-situ frozen hydrate electron microscopy techniques. The experimental conditions are modified to test the effects of undulation, electrostatic interactions, hydration and hydrophobic interactions on the adhesion and fusion process. This is the first systematic effort to understand the coupling between inter-and intra-aggregate interactions and the resulting structural modifications that occur when amphiphilic structures are brought into contact. A video recording system allows one to follow the fusion process in real time using a surface forces apparatus. Though a number of these apparatus exist in various laboratories, none is being deployed to study the dynamics of fusion as in this work. The combination of rapid freezing, artifact-free freeze-fracture and in-situ frozen-hydrated electron microscopy applied to amphiphilic structures is also unprecedented. The techniques present direct images of three-dimensional structural transitions with molecular resolution. This project should have a major impact on both the theory and practice of all phenomena involving interbilayer and intermembrane interactions. The expected new insights into the fundamental forces and molecular events accompanying the fusion of micelles, bilayers, vesicles, microemulsion droplets, foams, emulsions and surfactant- coated colloidal particles will be especially important as this has been the focus of much attention in the colloid and biological sciences. The stability of vesicles and their usefulness as drug carriers, the stability of colloidal dispersions, breaking and creating foams and emulsions, the effectiveness of surfactants in flotation, and the wear of boundary lubricants are all examples where understanding of basic mechanisms are still lacking. Of greatest possible importance is the ability to directly study the interactions of real biological membranes and other specific interactions involving biological macromolecules.

当双层、囊泡、微乳液液滴和生物膜等两亲结构接近和接触时，它们之间的力伴随着结构的弹性变形。 这些变形取决于聚集体间和聚集体内的力及其耦合。 该项目是利用直接力测量、冷冻断裂和原位冷冻水合物电子显微镜技术研究粘附、融合和伴随的结构变形。 修改实验条件以测试波动、静电相互作用、水合和疏水相互作用对粘附和融合过程的影响。 这是首次系统性地了解聚集体间和聚集体内相互作用之间的耦合以及两亲结构接触时发生的结构修饰。 视频记录系统允许人们使用表面力装置实时跟踪融合过程。 尽管不同的实验室中都存在许多这样的设备，但没有像这项工作那样被部署来研究聚变动力学。 快速冷冻、无伪影冷冻断裂和原位冷冻水合电子显微镜的结合应用于两亲结构也是前所未有的。 该技术以分子分辨率呈现三维结构转变的直接图像。 该项目将对涉及双层间和膜间相互作用的所有现象的理论和实践产生重大影响。 对伴随胶束、双层、囊泡、微乳液液滴、泡沫、乳液和表面活性剂涂覆的胶体颗粒融合的基本力和分子事件的预期新见解将尤其重要，因为这一直是胶体和生物科学中备受关注的焦点。 囊泡的稳定性及其作为药物载体的用途、胶体分散体的稳定性、泡沫和乳液的破裂和产生、浮选中表面活性剂的有效性以及边界润滑剂的磨损都是仍然缺乏对基本机制的理解的例子。 最重要的是能够直接研究真实生物膜的相互作用以及涉及生物大分子的其他特定相互作用。