GOALI: A GOALI Study of the Stability of Monolayers, Bilayers, and Multivesicular Lipsomes

GOALI：单层、双层和多囊泡脂质体稳定性的 GOALI 研究

• 批准号: 9634050
• 负责人: Jacob Israelachvili
• 金额: $ 22万
• 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: 1997
• 资助国家: 美国
• 起止时间: 1997-05-15 至 1999-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9634050&HistoricalAwards=false
• 关键词: GOALI; Study; Stability; Monolayers; Bilayers

ABSTRACT CTS-9634050 It is planned to pattern model biomembranes onto solid substrates via functionalized silane self assembled monolayers ("patterned SAMs") produced by microcontact printing on oxidized silicon or mica. The free ends of the silanes will be functionalized with specific reactive groups such as thiol-coupled gold colloids or ligand-receptor pairs such as biotinated lipid-streptavidin to anchor an otherwise free-floating bilayer at a pattern of discrete points. The unfunctionalized part of the substrate will be treated with a second silane terminated with a neutral group to prevent adhesion to the substrate. Bilayers incorporating biotinated or gold-colloid lipids will be deposited on these functionalized surfaces either by adsorption from vesicle solution or by Langmuir-Blodgett or Langmuir-Schaefer deposition, to bind to the SAM layer at discrete points. Alternatively, we can lithographically pattern a substrate via plasma-enhanced chemical vapor deposition of silicon oxide, then apply monolayers of functionalized silanes to anchor bilayers. The idea is to create the bilayer equivalent of a Langmuir monolayer in which we can study the morphology and interactions of nearly free-floating membranes with the Surface Forces Apparatus, fluorescence and Brewster angle microscopy (BAM), and AFM. In addition to studying membrane properties, patterning membranes is a first step toward biofunctionalizing semiconductors with a micronresolution technique similar to and compatible with microlithography for use in biosensors. An important part of this project is to study the long-term stability of surfactant and lipid structures on surfaces (2D assembly) and in solution (3D assembly). It is still not known whether many surfactant structures, such as circular or stripe domains in monolayers, or unilamellar vesicles in solution, are true equilibrium structures. This question is particularly important to creating membrane-based biosensors that require long-term stability and our GO ALI project of predicting drug release from the DepoTech Co.'s multivesicular liposomes (MVL). It is proposed to study these effects at the air-water interface in monolayers by constructing a completely sealed Langmuir trough to provide temperature and environment control. The surface pressure will be measured using a novel floating wire sensor the monolayers will be viewed by fluorescence microscopy and BAM. It is planned to investigate the long-term stability of domain structures at the airwater interface by continuously monitori.ng. Concurrent with these studies, freeze-fracture electron microscopy will be used to examine a novel multivesicular liposome (DepoFoam) drug delivery system in collaboration with the Depotech Co. The MVL are made from a water-organic-water double emulsion process and the structure is similar to a gas-liquid foam. The goal is to determine the effects of processing conditions, drug composition, and the progression to equilibrium on drug-release properties.

摘要CTS-9634050 计划通过在氧化硅或云母上微接触印刷产生的官能化硅烷自组装单层（“图案化SAM”）将模型生物膜图案化到固体基底上。 硅烷的自由端将用特定的反应性基团如硫醇偶联的金胶体或配体-受体对如生物素化的脂质-链霉亲和素官能化，以在离散点的图案处锚定否则自由浮动的双层。 基材的未官能化部分将用以中性基团封端的第二硅烷处理，以防止粘附到基材上。 结合生物素化或金胶体脂质的双层将通过从囊泡溶液中吸附或通过Langmuir-Blodgett或Langmuir-Schaefer沉积而沉积在这些功能化表面上，以在离散点处结合到SAM层。 或者，我们可以通过等离子体增强化学气相沉积氧化硅光刻图案的基板，然后应用功能化硅烷单层的锚双层。 我们的想法是创建一个朗缪尔单层的双层等效物，在其中我们可以研究的表面力装置，荧光和布鲁斯特角显微镜（BAM），和原子力显微镜几乎自由浮动的膜的形态和相互作用。 除了研究膜的性质，图案化膜是生物功能化半导体的第一步，其微分辨率技术类似于并兼容于用于生物传感器的微光刻技术。 该项目的一个重要部分是研究表面活性剂和脂质结构在表面（2D组装）和溶液（3D组装）中的长期稳定性。 许多表面活性剂结构，如单层中的环状或条纹状结构域，或溶液中的单层囊泡，是否是真正的平衡结构，目前还不清楚。 这个问题对于创建需要长期稳定性的膜基生物传感器和我们预测DepoTech Co.的多囊脂质体（MVL）。 建议通过构建完全密封的朗缪尔槽以提供温度和环境控制来研究单分子膜中空气-水界面处的这些效应。 表面压力将使用一种新型的浮线传感器测量，单分子膜将通过荧光显微镜和BAM观察。 计划通过连续监测来研究气水界面畴结构的长期稳定性。 与这些研究同时，冷冻断裂电子显微镜将用于检查一种新的多泡脂质体（DepoFoam）药物递送系统与Depotech公司合作。MVL由水-有机-水复乳工艺制成，结构类似于气液泡沫。 目的是确定加工条件、药物组合物和药物释放特性的平衡进展的影响。