IMR: Acquisition of a Light Scattering System for Research and Education at the Polymer/Colloid Interface

技术摘要。配备静态和动态在线光散射探测器的不对称场流分馏设备将能够高分辨率测量颗粒和组件的尺寸和分子量分布。该系统可以处理水或非水样品，将有利于以下主要项目：淀粉样纤维的形成，这是阿尔茨海默病的一个关键过程；响应的树状大分子超结构，设计用于捕获和释放客人，如药物、毒素和试剂；早期组装非共价稳定的聚合物凝胶的前体，有可能作为纳米级支架；评估设计用于生产响应性胶体晶体的二氧化硅-多肽复合颗粒；以及正在开发的用于人造皮肤的聚合物-粘土复合材料的相互作用。次级项目包括支持病毒制备和功能的表征、聚电解质的物理化学行为和新型锥形囊泡。感兴趣的颗粒的大尺寸和往往微妙的性质使得它们很难或不可能用凝胶渗透色谱来表征。其他与之竞争的方法，如低温电子显微镜，有时会受到制备伪影或欠采样误差的影响。大多数要研究的颗粒都带有电荷；因此，要求包括测量Zeta电位的设备，Zeta电位与溶液中分子或颗粒上的有效电荷有关。这也允许常规的生物物理测量，如蛋白质的等电点和在生物相关条件下其大小的细微变化。新设备将允许旧的光散射设备退役，然后在学生设计师手中重生。其结果将是一种超越商业上可用设计的仪器，用于微观流变学和快速自组装等应用。非技术摘要。所要求的设备可以测量纳米颗粒、聚合物及其聚集体的大小和质量，包括人工合成的和自然存在的。例如，阿尔茨海默病被认为是通过极小的蛋白质片段堆积成巨大的结构而进展的。所要求的设备将有助于评估旨在拦截这一过程的候选药物的疗效。同样的设备将用于表征新的合成材料，这些材料有可能携带药物，去除环境毒素，或以光学纯形式分离新材料。该请求的一个组成部分在公开可访问的实验室中并不广泛提供。它在路易斯安那州立大学校园的存在利用不断增长的项目来改善我们学生群体的产业拓展和多样性。该设备大大增加了路易斯安那州应用聚合物技术推广联盟，这是一个全州范围的大学联盟，其主要任务是在美国最贫穷的地区之一发展经济。学术实验室中缺乏类似的设备，这使得这些设备吸引了更多的学生，包括由NSF-REU支持的暑期实习生，以及一项由NIH资助的针对代表性不足群体的新倡议。该设备支持与德克萨斯大学泛美分校的一项新的研究合作伙伴关系，该大学培训的学生主要是拉丁裔。这些设备将在路易斯安那州立大学的一门新的、跨部门的、团队授课的课程中发挥关键作用，这是路易斯安那州立大学第一门涉及胶体科学及其与纳米研究和大分子的接口的课程。

Technical Abstract. An asymmetric field flow fractionation device with on-line light scattering detectors, both static and dynamic, will permit high-resolution measurements of the size and molecular weight distributions of particles and assemblies. The system, which can handle aqueous or non-aqueous samples, will benefit these primary projects: formation of amyloid fibrils, which is a key process in Alzheimer's disease; responsive dendrimer superstructures designed to trap and release guests, such as drugs, toxins, and reagents, on command; early assembly of precursors to noncovalently stabilized polymer gels with potential as nanoscale scaffolds; evaluation of silica-polypeptide composite particles designed to produce responsive colloidal crystals; and, interactions in polymer-clay composites being developed for artificial skin applications. Secondary projects include characterization in support of virus preparation and function, physicochemical behavior of polyelectrolytes, and novel cone-shaped vesicles. The large size and often-delicate nature of the particles of interest makes them difficult or impossible to characterize by gel permeation chromatography. Other competing methods, such as cryo electron microscopy, are sometimes subject to preparation artifacts or undersampling errors. Most of the particles to be investigated carry an electrical charge; therefore, the request includes equipment to measure zeta potential, which is related to the effective charge on a molecule or particle in solution. This also permits routine biophysical measurements, such as the isoelectric point of proteins and subtle changes in their size under biologically relevant conditions. The new equipment will permit an older light scattering device to be retired and then reborn in the hands of student designers. The outcome will be an instrument that transcends commercially available designs for applications such as microrheology and rapid self-assembly. Non-technical Abstract. The requested equipment can measure the size and mass of nanoparticles, polymers and their aggregates, both synthetic and naturally occurring. For example, Alzheimer's disease is thought to progress through the accretion of very small protein fragments into huge structures. The requested equipment will help assess the efficacy of drug candidates designed to intercept this process. The very same equipment will be used to characterize new synthetic materials that have the potential to carry drugs, remove environmental toxins, or isolate new materials in optically pure form. One component of the request is not widely available in publicly accessible laboratories. Its presence on the Louisiana State University campus leverages growing programs to improve both industrial outreach and diversity of our student body. The equipment adds significantly to the Louisiana Applied Polymer Technology Extension Consortium, a statewide university coalition whose primary mission is economic development in one of the poorest regions of the United States. The paucity of similar equipment in academic laboratories makes the equipment appealing to a wider audience of students, including summer interns supported by NSF-REU and a new, NIH-funded initiative targeting under-represented groups. The equipment supports a new research partnership with the University of Texas-Pan American, which trains a largely Latino student body. The equipment will play a key role in a new, interdepartmental, team-taught course, the first at Louisiana State University to address colloid science and its interface to nanoscale research and macromolecules.