Collaborative Research: Active Transport of Lipid Vesicles in Osmotic Gradients

合作研究：渗透梯度下脂质囊泡的主动运输

• 批准号: 1804332
• 负责人: Kyle Bishop
• 金额: $ 29万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1804332&HistoricalAwards=false
• 关键词: Collaborative; Research; Active; Transport; Lipid

The membranes of living cells are highly and selectively permeable to water. Variations in the osmotic pressure due to dissolved molecules drives water transport across the membrane, thereby inducing fluid flows and membrane motions. Such flows are critical to biological processes such as the regulation of cell water content, the transport of intra- and extracellular compartments, and the migration of cells in tissues. Despite their importance, the fundamental fluid mechanics underlying these processes remains poorly understood. This project aims to advance our understanding of fluid flows and membrane motions driven by osmotic gradients. Such knowledge will further enable biotechnologies involving the extraction, separation, and delivery of extracellular vesicles, which are actively pursued as diagnostic and therapeutic tools for treating human diseases. The project will also provide educational opportunities to middle and high school students from underrepresented groups through laboratory tours and summer research experiences.The central goal of the proposed work is to develop experimental platforms and theoretical models that elucidate the physical mechanisms underlying the motion of lipid vesicles in osmotic gradients ? a process called osmophoresis. Using microfluidic systems, we will quantify vesicle velocity as a function of membrane properties such as vesicle size, permeability, rigidity, tension / excess area, and surface charge as well as environmental properties such as solute type, gradient magnitude, fluid viscosity, and confinement. Notably, we will use lipid membranes incorporating aquaporin water channels to create high permeability vesicles that mimic native exosomes. The proposed experiments will provide definitive data with which to enhance our understanding of osmophoresis and its impact on vesicle transport in biology. The proposed theory will integrate previous work on the osmophoresis of rigid spherical membranes with models of membrane dynamics that account for deformation and flow within incompressible lipid bilayers. Our theoretical investigations will ultimately reproduce and explain experimental observations of rapid vesicle motions in osmotic gradients. Finally, the proposed demonstration of osmophoretic vesicle sorting will provide a fundamental basis for biotechnologies involving the separation and characterization of extracellular vesicles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

活细胞的膜对水具有高度和选择性的渗透性。由于溶解分子引起的渗透压变化驱动水在膜上的运输，从而诱导流体流动和膜运动。这种流动对细胞含水量的调节、细胞内和细胞外区室的运输以及细胞在组织中的迁移等生物过程至关重要。尽管它们很重要，但这些过程背后的基本流体力学仍然知之甚少。该项目旨在促进我们对渗透梯度驱动的流体流动和膜运动的理解。这些知识将进一步推动细胞外囊泡提取、分离和输送等生物技术的发展，这些技术正被积极用作治疗人类疾病的诊断和治疗工具。该项目还将通过实验室参观和夏季研究经验，为来自代表性不足群体的初高中学生提供教育机会。提出的工作的中心目标是建立实验平台和理论模型，阐明渗透梯度中脂质囊泡运动的物理机制。这个过程叫做渗透。使用微流体系统，我们将量化囊泡速度作为膜特性的函数，如囊泡大小、渗透率、刚性、张力/过剩面积、表面电荷，以及环境特性，如溶质类型、梯度大小、流体粘度和约束。值得注意的是，我们将使用含有水通道蛋白水通道的脂质膜来创建模仿天然外泌体的高渗透性囊泡。提出的实验将提供明确的数据，以加强我们对渗透及其对生物学中囊泡运输的影响的理解。所提出的理论将整合先前关于刚性球形膜渗透的研究与膜动力学模型，这些模型解释了不可压缩脂质双层内的变形和流动。我们的理论研究将最终重现和解释渗透梯度中快速囊泡运动的实验观察。最后，本文提出的渗透囊泡分选将为涉及细胞外囊泡分离和表征的生物技术提供基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Measurement and mitigation of free convection in microfluidic gradient generators

• DOI: 10.1039/c8lc00526e
• 发表时间: 2018-11-21
• 期刊: LAB ON A CHIP
• 影响因子: 6.1
• 作者: Gu, Yang;Hegde, Varun;Bishop, Kyle J. M.
• 通讯作者: Bishop, Kyle J. M.