Towards Scaffolds for Rational Self Assembly: Investigating Nucleation Dependent Growth and Self-Healing of Co-Assembled Amyloid Nanotubes

ID：MPS/DMR/BMAT(7623)0907435 PI：BERLAND，Keith ORG：Emory University标题：Towing Scaffods for Rational Self Assembly：Investigating Amyloid NanotubeIntelecultube：研究共组装的淀粉样纳米管的成核依赖生长和自修复研究优点：PI观察到，在有序组装之前，淀粉样蛋白形成的多肽聚集成几微米大小的聚集体，其形态与有序的纤维或纳米管不同，而且这种增长似乎源于这些聚集体结构中多肽构象的结构重组和相互作用。这些初步数据代表了对淀粉样蛋白成核的第一次直接观察，努力加深对这些纳米材料成核、生长和自我修复特性的物理机制的理解，对于推动它们作为功能性的、合理设计的分子自组装平台的潜在用途至关重要。已经开发了一个模型系统，其中荧光肽被掺入到高度有序的组装中，这些构造为加深对组装的基本途径的理解提供了独特的机会。通过将这个定义良好和结构特征明确的模型系统与最先进的荧光显微镜相结合，该研究计划有能力极大地促进对这些材料的理解。具体地说，有人建议应用荧光成像、寿命成像、波动光谱和光漂白测量来定义淀粉样蛋白成核、延伸和生长以及淀粉样蛋白纳米管的自愈特性。重点是：目标1：淀粉样核形成。表征聚集体结构、结构变化以及与淀粉样蛋白成核相关的动力学。这些测量将利用实验模型系统，该系统已经发现了第一个直接观察到的淀粉样核形成。目标2：纳米管的伸长和生长。直接观察伸长动力学，并定量测量单个组件的生长速度，以更好地表征传播过程。这些测量可以确定生长是单向的还是双向的，结合寿命显微镜可以确定成熟的结构是直接组装的，还是初始组装后的松弛过程产生的。目的3：淀粉样蛋白结构的肽交换和自我修复。有用的纳米级生物材料需要自我修复能力，通过这种能力，受损区域可以重新组装或自我修复。初步证据表明，淀粉样蛋白结构具有这种能力。这个目标集中在了解自我修复机制所需的详细实验上。BROADER影响：拟议的研究代表了埃默里大学伯兰德(物理系)和林恩(化学系)实验室的合作努力。这项研究的跨学科性质为埃默里社区内外的新培训机会提供了机会。教学和研究合作的一个优势是学生接受了物理光谱学、化学合成和分析技术方面的培训，这些技能是从事跨学科研究课题所必需的。该协会组织了一系列名为《秩序的起源》的新生研讨会课程。(根据埃默里研究人员的最新发现)，向本科生介绍尖端研究。PI和最近的一位博士后助理开发了这门课程的材料，用于向一年级学生教授荧光和涨落及其在现代研究中的应用。这项建议的两个私人助理都有监督本科生研究项目的历史，每年提供学年和暑期学生培训。在埃默里社区之外，两家私人投资机构还利用研究实验室与大学以外的人分享对科学研究的热情和兴奋，包括与其他机构的研究人员以及高中生和高中教师进行互动。

ID: MPS/DMR/BMAT(7623) 0907435 PI: Berland, Keith ORG: Emory UniversityTitle: Towards Scaffolds for Rational Self Assembly: Investigating Nucleation Dependent Growth and Self-Healing of Co-Assembled Amyloid NanotubesINTELLECTUAL MERIT: The PIs have observed that prior to ordered assembly, the amyloid forming peptides aggregate into several-micron sized aggregates with morphology that is distinct from the ordered fibers or nanotubes, and that the growth appears to originate from structural reorganization of peptide conformations and interactions within these aggregate structures. These preliminary data represent the first direct observation of amyloid nucleation, and working towards a deeper understanding of the physical mechanisms governing nucleation, growth, and self-healing properties of these nanomaterials is essential for advancing their potential use as functional, rationally-designed platforms for molecular self-assembly. A model system has been developed in which fluorescent peptides are incorporated into the highly ordered assemblies, and these constructs provide a unique opportunity to deepen understanding of the fundamental pathways for assembly. By combining this well defined and structurally characterized model system with state-of-the-art fluorescence microscopy, the research plan has the capability to dramatically advance understanding of these materials. Specifically, it is proposed to apply fluorescence imaging, lifetime imaging, fluctuation spectroscopy, and photobleaching measurements to define amyloid nucleation, elongation and growth as well as the self-healing properties of amyloid nanotubes. The focus will be: Aim 1: Amyloid nucleation. Characterize aggregate structures, structural changes, and associated kinetics involved in amyloid nucleation. These measurements will exploit the experimental model system which has uncovered the first direct observation of amyloid nucleation. Aim 2: Nanotube elongation and growth. Directly observe elongation kinetics and make quantitative measurements of single assembly growth rates to better characterize propagation processes. These measurements can determine whether growth is uni- or bidirectional, and coupled with lifetime microscopy can determine whether mature structures are directly assembled or result from relaxation processes following initial assembly. Aim 3: Peptide exchange and self healing of amyloid structures. Useful nanoscale biomaterials require self-healing capabilities, by which damaged regions can reassemble or self-repair. Initial evidence suggests amyloid structures possess this capability. This aim focuses on detailed experiments that are required to understand the self-repair mechanisms.BROADER IMPACTS: The proposed studies represent a collaborative effort of the Berland (Department of Physics) and Lynn (Department of Chemistry) labs at Emory University. The interdisciplinary nature of the research provides the opportunity for new training opportunities, both within the Emory community and beyond. A strength of the teaching and research collaboration is that the students are trained in the physical spectroscopy, chemical synthesis, and the analysis techniques necessary to work on interdisciplinary research topics. The co-PI organizes a series of freshman seminar courses called ?Origins of ORDER? (On Recent Discoveries by Emory Researchers) that introduce undergraduate students to cutting edge research. The PI and a recent postdoctoral associate have developed materials for this course, which were used to teach freshmen about fluorescence and fluctuations, and their applications in modern research. Both PIs for this proposal have a history of supervising undergraduate research projects, providing academic year and summer student training each year. Beyond the Emory community both PIs have also used the research laboratory to share enthusiasm and excitement for scientific research with those outside the University, including interacting with researchers from other institutions as well as high school students and high school teachers.