Collaborative Research: Fate, Transport, and Organismal Uptake of Rod-Shaped Nanomaterials

CBET 1336353目前对刚性高度各向异性纳米结构的环境影响知之甚少。具有高纵横比（AR =长度：直径）的纳米棒是具有许多潜在应用的令人兴奋的纳米材料类别。然而，迄今为止，只有有限数量的研究检查了这些细长纳米材料的环境命运。鉴于已经明确表明各向异性会影响纳米棒与生物系统的相互作用，这一领域的工作缺乏尤其令人惊讶。驱动目前努力的基本假设是AR和表面化学的变化将改变决定河流系统中纳米棒命运的机制和动力学。为了验证这一假设，PI制定了一项研究计划，包括四个高度相关的项目任务：在任务1中，我们将合成具有不同AR的金纳米棒，然后我们将使用一系列与环境相关的金属氧化物（例如，SiO2，γ-Fe 2 O3，CeO 2），以获得一套表现出形状和表面化学异质性的纳米材料。然后，这些纳米棒将用于研究，以评估纳米棒聚集（任务2），纳米棒沉积（任务3）和过滤器喂养双壳贝类河蚬（任务4）的吸收。完成每一项任务本身都是一项重要的任务，但我们制定了一个有凝聚力的研究计划，其中任何一项任务中获得的知识都可以用于帮助完善整个研究计划。智力优势：各向异性纳米颗粒的形状和尺寸越来越多样化，数量也越来越多。目前，人们对这些高度复杂的纳米材料的环境影响知之甚少。本文提出的努力将提供一个基本的基础，材料的各向异性如何决定纳米材料的命运在环境矩阵的描述。这一努力的预期智力成果是i）作为纵横比和溶液化学的函数的纳米棒聚集动力学和分形维数的系统检查（ii）通过颗粒性质（AR，表面化学）和收集器参数（例如，收集器尺寸和表面粗糙度）;以及（iii）量化AR对无处不在的过滤器进料器C吸收纳米材料的影响。fluminea。虽然我们的重点是金和金核纳米棒，但预计所获得的结果可以转化为其他各向异性材料。更广泛的影响：已经制定了一个多层面的方法来应对更广泛的影响。这种方法利用了三个合作机构的现有项目，同时努力整合各个小组的工作。研究、传播和外联。PI将通过弗吉尼亚州、南卡罗来纳州和伊利诺伊州现有的社区项目共同推广和传播研究成果。此外，该项目的成果将通过同行审查出版物和在相关会议上介绍的传统途径向广大技术受众广播。外联工作将针对当地高中的少数族裔学生。本科研究。 所有三个合作机构都将提供本科生研究机会。在他们的职业生涯中，PI在他们的实验室中共同支持了90多名本科生研究人员（其中很大一部分是历史上代表性不足的科学和工程群体的成员），这一努力将提供额外的本科生研究机会。本科和研究生教育。在这项工作中提出的研究结合了纳米材料的合成和表征技术与胶体物理原理的方式，是不是经常发现在本科化学或环境工程课程。鉴于这一事实，所有三个PI都将参与课堂材料的开发和制作（例如，讲座，演示）的基础上，这项研究，将纳入所有三个机构的课程。

CBET 1336353There is currently very little known about the environmental implications of rigid highly anisotropic nanostructures. Nanorods possessing high aspect ratios (AR = length:diameter) are an exciting nanomaterial class with many potential applications. To date, however, only a limited number of studies have examined the environmental fate of these elongated nanomaterials. The lack of work in this area is particularly surprising given that it has been definitively shown that anisotropy affects how nanorods interact with biological systems. The underlying hypothesis driving the present effort is that changes in AR and surface chemistry will alter the mechanisms and kinetics dictating nanorod fate in riverine systems. To test this hypothesis the PIs have developed a research plan that consists of four highly inter-related project tasks: In Task 1 we will synthesize gold nanorods with varying AR and we will then functionalize them using a range of environmentally relevant metal oxides (e.g., SiO2, gamma-Fe2O3, CeO2) to obtain a suite of nanomaterials that exhibit both shape and surface chemical heterogeneity. These nanorods will then be used in studies to evaluate nanorod aggregation (Task 2), nanorod deposition (Task 3), and uptake by the filter feeding bivalve Corbicula fluminea (Task 4). Completion of each of these tasks is an important undertaking in its own right; however, we have developed a cohesive research plan in which the knowledge gained in any one task is used to help refine the overall research plan.Intellectual Merit :Anisotropic nanoparticles are being produced in an ever-expanding variety of shapes and sizes in ever-increasing quantities. Presently ery little is known about the environmental implications of these highly complex nanomaterials. The effort proposed herein will provide a fundamental basis for the description of how material anisotropy dictates nanomaterial fate in environmental matrices. The expected intellectual outcomes of this effort are i) systematic examination of nanorod aggregation kinetics and fractal dimension as a function of aspect ratio and solution chemistry (ii) delineation of deposition mechanisms by the systematic variation of particle properties (AR, surface chemistry) and collector parameters (e.g., collector size and surface roughness) in column studies; and (iii) quantification of the effects of AR on nanomaterial uptake by the ubiquitous filter feeder C. fluminea. Although our focus is on gold and gold-core nanorods, the results obtained are expected to be translatable to other anisotropic materials. Broader Impacts :A multi-dimensional approach to broader impacts has been developed. This approach leverages existing programs at the three collaborating institutions while working to integrate efforts across the groups. Research dissemination and outreach. The PIs will collectively promote and disseminate the research results through existing community programs in Virginia, South Carolina, and Illinois. In addition, the results of this project will be broadcast to a broad technical audience through the traditional pathways of peer-reviewed publications and presentations at relevant conferences. Outreach efforts will target minority students in local high schools. Undergraduate research. Undergraduate research opportunities will be made available at all three collaborating institutions. Over the course of their careers, the PIs have collectively supported over 90 undergraduate researchersin their laboratories (a significant percentage of whom are members of historically under-represented groups in science and engineering) and this effort will provide additional undergraduate research opportunities. Undergraduate and graduate education. The research proposed in this effort combines nanomaterial synthesis and characterization techniques with colloidal physical principles in a manner that is not routinely found in undergraduate chemistry or environmental engineering curricula. Given this fact, all three PIs will take part in the development and production of classroom material (e.g., lectures, demonstrations) based upon this research that will be incorporated into courses at all three institutions.