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

弗朗西斯/普渡/0651942智力功绩。该项目研究如何了解和控制表面活性剂、脂类和蛋白质在空气/水界面上的吸附程度和速度，重点放在主要的基本物理化学、生物物理和工程现象和机制上。这种吸附决定了平衡和动态表面张力，从而影响包括气泡、液滴和液体射流在内的自由表面流动，并控制着肺泡内的压力和质量传递。其独特之处包括：(I)直接探测表面活性剂、脂类、蛋白质及其混合物的水溶液或分散体的界面层，使用定量红外反射吸收光谱和椭偏测量法；(Ii)通过改进脂类分散体制备方法，控制不溶性脂类的颗粒或分子吸附；(Iii)了解抑制肺表面活性物质的脂类和血清蛋白(白蛋白或纤维蛋白原)的竞争吸附；(Iii)研究脂类在表面压缩过程中产生极低动态表面张力的速率和机制；(Iv)研究脂类可将可溶性蛋白质排除或排出界面区的机制；及(V)蛋白质与脂类在原液和表面的相互作用，以开发生物相容的脂质体制剂。结果与喷墨打印工艺、农业喷雾、DNA和蛋白质微阵列以及受泡沫形成和稳定性影响的工艺相关。一个重要的生物医学应用，开发作为肺表面活性物质替代制剂的长期潜在用途的脂质制剂，是一个焦点领域。脂类分散体的动态表面性质与分散颗粒、脂质体或囊泡的大小和形态有关。该项目的科学独到之处在于了解如何通过控制脂肪和蛋白质在空气-水界面上的整体和表面相互作用来控制它们的吸附。该方法的独特之处在于使用了严格的直接探针和定量工程建模原理，对流体界面和水溶液中的脂类/蛋白质相互作用进行了理性的理解。主要的社会益处包括：(I)了解如何使用新配方治疗早产儿和成人的肺泡呼吸系统疾病；以及(Ii)了解如何通过使用与第一种脂类混合的第二种脂类来控制脂质体或囊泡与血清蛋白的聚集，从而抑制与蛋白质的聚集。上述许多应用程序的知识库将大大扩展。这一结果可能导致与医学研究人员或专业人员以及处理此类应用的工业和学术研究人员建立合作伙伴关系。这项研究的目的是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。某些成果将用于研究生和本科课程的教学。开发和完善表面层表征将改善界面、生物医学、生化和矿物工程方面的研究和教育基础设施。PI.致力于为这个项目招收研究生和本科生的多样性，并在过去五年里与代表不足的团体的几名成员进行了合作。他将招募普渡大学“冲浪”项目的少数族裔学生，在该项目中，来自普渡大学或其他学校的少数族裔高年级学生被积极招募、聘用、指导并建议他们继续研究生或专业学习。

Franses / Purdue / 0651942Intellectual Merit. The project examines how to understand and control the extent and rate of adsorption of surfactants, lipids, and proteins at air/water interfaces by focusing on the prevailing fundamental physicochemical, biophysical, and engineering phenomena and mechanisms. Such adsorption determines the equilibrium and dynamic surface tension, which affects free surface flows involving bubbles, drops, and liquid jets, and controls pressure and mass transfer in lung alveoli. Unique features include: (i) direct probing of the interfacial layers of aqueous solutions or dispersions of surfactants, lipids, proteins, and their mixtures, with quantitative infrared reflection absorption spectroscopy and ellipsometry; (ii) control of particulate or molecular adsorption of insoluble lipids by developing improved methods of lipid dispersion preparation; (iii) understanding of competitive adsorption of lipids and serum proteins (albumin or fibrinogen) which inhibit lung surfactant; (iii) studies of rates and mechanisms by which lipids produce very low dynamic surface tensions, less then 10 mN/m during surface compression; (iv) studies of mechanisms by which lipids can exclude or expel soluble proteins from the interfacial region; and (v) interactions of proteins with lipids in bulk solution and on surfaces, for developing biocompatible liposome formulations . The results are relevant to inkjet printing processes, agricultural sprays, DNA and protein microarrays, and processes affected by foam formation and stability. An important biomedical application, developing lipid formulations for long-term potential uses as lung surfactant replacement formulations, is an area of focus. The dynamic surface properties of lipid dispersions are related to the size and morphology of the dispersed particles, liposomes or vesicles. The scientific uniqueness of this project is the understanding of how to control lipid and protein adsorption at the air-water interface by controlling both their bulk and surface interactions. The unique aspect of the approach is the use of rigorous direct probes and quantitative engineering modeling principles in developing a rational understanding of lipid/protein interactions at fluid interfaces and in aqueous solution.Broader Impacts. Major societal benefits include: (i) understanding how to treat alveolar respiratory diseases of premature infants and adults with new formulations; and (ii) understanding how aggregation of liposomes or vesicles with serum proteins can be controlled by using a second lipid mixed with first so that aggregation with proteins is inhibited. The knowledge base for many of the above applications will be substantially expanded. The results may lead to partnerships with medical researchers or professionals, and with industrial and academic researchers dealing with such applications. This research aims at effective training of graduate and undergraduate students, who will be exposed to state-of-the-art experimentation and modeling. Certain results will be used in teaching of graduate and undergraduate courses. 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 under-represented groups over the past five years. He will recruit for minority students from the Purdue "Surf" program, in which minority seniors, from Purdue or other schools, are actively recruited, hired, mentored, and advised to pursue graduate or professional studies.