Direct Probing and Modeling of Adsorbed Layers of Surfactant/Lipid/Protein Mixtures at Air/Water Interfaces

该健康相关项目通过了解基本现象和机制，研究如何测量、表征和控制表面活性剂、脂质和蛋白质在空气/水界面的吸附程度和速率。这种吸附决定了平衡和动态表面张力，影响气泡、液滴和液体射流的自由表面流动。对恒面积和脉动面积条件下的动态表面张力进行了测量和建模。独特的特点包括：(i)直接探测水溶液的界面层或表面活性剂、脂质、蛋白质的分散体，以及它们的混合物，定量椭偏仪和红外光谱；（ii）通过控制脂质分散制备方法，控制不溶性脂质的吸附；（iii）了解脂质和血清蛋白（白蛋白或纤维蛋白原）的竞争性吸附；（iv）胶束溶解和扩散模型及其对吸附动力学的影响；(v)脂质到达表面的速率和机制的研究，在那里它们产生非常低的动态表面张力（在表面压缩期间小于10 mN/m）；（六）研究脂质从界面区域排除或排出可溶性蛋白质的速率和机制。本文首次利用定量红外光谱和椭偏仪对脂溶性蛋白分散体的表层组成进行了研究。热力学和界面传质原理首次应用于预测和控制脂质如何从界面吸附和排出蛋白质。这对于受泡沫稳定性和破裂影响的过程（如生物反应器、洗衣机和泡沫基分离）以及肺表面活性剂的设计和配方可能很重要。这些结果在涉及液滴变形和破裂的过程中很重要，如DNA和蛋白质微阵列，喷墨打印过程，以及农业农药喷雾剂的设计和使用。由于白蛋白和纤维蛋白原血清蛋白可渗漏至肺泡并抑制肺表面活性物质的功能，了解影响其移位的因素可在生物医学工程中应用于治疗急性呼吸窘迫综合征（ARDS）肺损伤。这可能对有效治疗或减轻婴儿和成人呼吸道疾病有直接和间接的影响。其他社会影响可以得到改善，农药配方可以更精简，以减少环境污染。这项研究还将有效地培养研究生和本科生，他们将接触到最先进的实验和建模。研究结果将部分用于研究生课程和本科生课程。发展和完善表面层表征将改善界面、生物医学、生物化学和矿物工程的研究和教育基础设施。私家侦探致力于为该项目招募研究生和本科生的多样性，并在过去五年中与一些代表性不足的群体成员合作。研究结果可能导致与医学研究人员或专业人员以及处理表面活性剂、脂质和蛋白质应用的工业和学术研究人员建立伙伴关系。

ABSTRACT - 0457289Purdue UniversityProject Summary The health related project examines how to measure, characterize, and control the extent and rate of adsorption of surfactants, lipids, and proteins at air/water interfaces by understanding the fundamental phenomena and mechanisms. Such adsorption determines the equilibrium and dynamic surface tension, which affects free surface flows involving bubbles, drops, and liquid jets. The dynamic surface tension at constant and pulsating area condition is measured and modeled. Unique features include: (i) direct probing of the interfacial layers of aqueous solutions or dispersions of surfactants, lipids, proteins, and their mixtures with quantitative ellipsometry and infrared spectroscopy; (ii) control of adsorption of insoluble lipids by controlling the method of lipid dispersion preparation; (iii) understanding of competitive adsorption of lipids and serum proteins (albumin or fibrinogen); (iv) models of micellar dissolution and diffusion, and their effect on adsorption dynamics; and (v) studies of rates and mechanisms by which lipids reach the surface where they produce very low dynamic surface tensions (less then 10 mN/m during surface compression); and (vi) studies of rates and mechanisms by which lipids can exclude or expel soluble proteins from the interfacial region. The surface layer composition of lipid/soluble protein dispersions is probed for the first time by quantitative IR spectroscopy and ellipsometry. Thermodynamic and interfacial mass transfer principles are applied for the first time for predicting and controlling how lipids can adsorb and expel proteins from the interface. This could be important for processes affected by foam stability and breakup, such as bioreactors, washing machines, and foam-based separations, and in lung surfactants design and formulations. The results are important in processes involving drop deformation and breakup, as in DNA and protein microarrays, inkjet printing processes, and the design and uses of agricultural pesticide sprays. Since albumin and fibrinogen serum proteins can leak to the alveoli and inhibit the function of lung surfactant, understanding the factors which affect their displacement could lead in biomedical engineering applications of treatment of lungs injured by the acute respiratory distress syndrome (ARDS). This may have direct and indirect implications in effectively treating or alleviating infant and adult respiratory diseases. Other societal impacts could be improved and leaner pesticide formulations, for reducing environmental pollution. This research will also lead to effective training of graduate and undergraduate students, who will be exposed to state-of-the-art experimentation and modeling. The results will be used in part in a graduate course and an undergraduate course. Developing and refining surface layer characterization will improve the infrastructure of research and education in interfacial, biomedical, biochemical, and mineral engineering. The P.I. is committed to diversity in recruiting graduate and undergraduate students for this project, and has worked with several members of underrepresented groups over the past five years. The results may lead to partnerships with medical researchers or professionals and with industrial and academic researchers dealing with surfactant, lipid, and protein applications.