Collaborative Research: Mechanics of fusion of dissimilar lipid bilayers and multi-lamellar vesicles

合作研究：不同脂质双层和多层囊泡的融合机制

基本信息

批准号：
1705775
负责人：
David Weitz
金额：
$ 21.7万
依托单位：
Harvard University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1705775&HistoricalAwards=false
关键词：
Collaborative Research Mechanics fusion dissimilar

项目摘要

Vesicles are small sacs surrounded by a lipid bilayer membrane and enclosing biomolecules essential for inter- and intra-cellular communication, transportation, and other physiological functions. Vesicles can fuse with cells and other vesicles to deliver designated drugs, segments of DNA for gene therapy, and neurotransmitters in a wide spectrum of medical treatments. Understanding the mechanism of membrane fusion is critical to interpret natural phenomena and to design and facilitate drug delivery. The overarching goal of this collaborative project between Northeastern University and Harvard University is to investigate the underlying biomechanics and biochemistry of membrane and liposome fusion by coordinated experiments and theoretical modeling. Vesicles with ranges of lipids and pseudo-lipids, microstructures, and size will be fabricated using specialized microfluidic devices. Mechanical characterization and intermediate steps of fusion under physiologically relevant conditions will be performed using atomic force microscopy. A mechanistic model of vesicle fusion, including membrane properties and inter-surface forces, will be developed to reveal molecular and membrane interactions. Outcomes of this study will lead to new insights into transport processes that are ubiquitous in mammalian cells, as well as guidelines to fabricate synthetic vesicles for drug delivery. The project will involve participation of students at all academic levels. Research outputs will be incorporated into undergraduate and graduate level courses at both universities. Educational videos will be developed to demonstrate vesicle dynamics for K-12 students and for the general public.The goal of this award is to investigate the underlying principles of fusion of similar and dissimilar lipid bilayers and vesicles and to develop a universal fusibility index by probing an extensive experimental parameter space. A wide range of known lipids relevant to drug delivery, lipids derived from healthy and diseased cell lines, and co-block polymer as pseudo lipids will be investigated. New microfluidics devices will be designed and built to manufacture homogeneous, heterogeneous, and multi-lamellar vesicles, with a wide range of diameters. Atomic force microscopy will be used to determine membrane properties of single liposomes in compression mode, as well as the energy barrier involved in hemifusion and fusion of two similar and dissimilar vesicles under physiologically relevant conditions. Hemifusion and fusion will be monitored in-situ by fluorescence microscopy, as well as a fluorescence resonance energy transfer technique. We will test the hypothesis that mechanics in terms of internal and intersurface forces, large deformation of the vesicles and associated strain energy, and statistical mechanics of surface domains plays a significant role in vesicle fusion. The fusibility index will be derived as a function of material properties of lipid membranes, vesicle geometry, interface and surface chemistry, and physiological environments, based on fundamental engineering principles.

囊泡是由脂质双层膜包围的小囊，其内含细胞间和细胞内通讯、运输和其他生理功能所必需的生物分子。囊泡可以与细胞和其他囊泡融合，以输送指定药物、用于基因治疗的 DNA 片段以及多种医学治疗中的神经递质。了解膜融合机制对于解释自然现象以及设计和促进药物输送至关重要。东北大学和哈佛大学之间的这个合作项目的总体目标是通过协调实验和理论建模来研究膜和脂质体融合的基础生物力学和生物化学。具有各种脂质和假脂质、微观结构和尺寸的囊泡将使用专门的微流体装置来制造。将使用原子力显微镜进行机械表征和生理相关条件下融合的中间步骤。将开发囊泡融合的机制模型，包括膜特性和表面间力，以揭示分子和膜的相互作用。这项研究的结果将为哺乳动物细胞中普遍存在的运输过程带来新的见解，并为制造用于药物输送的合成囊泡提供指导。该项目将涉及所有学术水平的学生的参与。研究成果将纳入两所大学的本科和研究生课程。将制作教育视频，向 K-12 学生和公众展示囊泡动力学。该奖项的目标是研究相似和不相似的脂质双层和囊泡融合的基本原理，并通过探索制定通用的融合性指数广泛的实验参数空间。将研究与药物递送相关的多种已知脂质、源自健康和患病细胞系的脂质以及作为假脂质的共嵌段聚合物。新的微流体装置将被设计和建造，以制造具有各种直径的均质、异质和多层囊泡。原子力显微镜将用于确定压缩模式下单个脂质体的膜特性，以及在生理相关条件下两个相似和不同的囊泡的半融合和融合所涉及的能量屏障。半融合和融合将通过荧光显微镜以及荧光共振能量转移技术进行原位监测。我们将测试以下假设：内力和表面间力、囊泡大变形和相关应变能以及表面域统计力学在囊泡融合中发挥重要作用。基于基本工程原理，可熔性指数将作为脂膜材料特性、囊泡几何形状、界面和表面化学以及生理环境的函数而导出。