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

技术摘要。 一个不对称的场流分馏装置与在线光散射检测器，静态和动态的，将允许高分辨率的测量颗粒和组件的大小和分子量分布。 该系统可以处理水性或非水性样品，将有利于这些主要项目：淀粉样蛋白原纤维的形成，这是阿尔茨海默病的关键过程;响应树枝状聚合物超结构设计用于捕获和释放客人，如药物，毒素和试剂，在命令下;早期组装非共价稳定的聚合物凝胶前体，具有纳米级支架的潜力;二氧化硅-多肽复合颗粒的评估，旨在产生响应胶体晶体;和，在聚合物-粘土复合材料的相互作用正在开发的人工皮肤应用。 次要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通常精细的性质使得它们难以或不可能通过凝胶渗透色谱法表征。 其他竞争方法，如冷冻电子显微镜，有时会受到准备工件或欠采样误差。 大多数待研究的颗粒都带有电荷;因此，请求包括测量zeta电位的设备，zeta电位与溶液中分子或颗粒的有效电荷有关。 这也允许常规的生物物理测量，例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设计的工具，用于微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合成和天然存在的纳米颗粒、聚合物及其聚集体的大小和质量。 例如，阿尔茨海默病被认为是通过非常小的蛋白质片段堆积成巨大的结构而发展的。 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功效。 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，或以光学纯的形式分离新材料。 该请求的一个组成部分在公众可进入的实验室中并不普遍。 它在路易斯安那州州立大学校园的存在利用不断增长的计划，以提高我们的学生群体的工业推广和多样性。 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，一个全州范围的大学联盟，其主要使命是在美国最贫穷的地区之一的经济发展。 学术实验室中类似设备的缺乏使得设备吸引了更广泛的学生群体，包括NSF-REU支持的暑期实习生和NIH资助的针对代表性不足群体的新举措。 该设备支持与德克萨斯大学泛美分校（University of Texas-Pan American）建立新的研究伙伴关系，该大学主要培养拉丁裔学生。 该设备将在一个新的跨部门的团队授课课程中发挥关键作用，这是路易斯安那州立大学第一个解决胶体科学及其与纳米级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.