Influence of diameter and chirality of single-walled carbon nanotubes on their fate and effects in the aquatic environment

单壁碳纳米管的直径和手性对其在水生环境中的命运和影响的影响

• 批准号: 0933484
• 负责人: Navid Saleh
• 金额: $ 39.93万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933484&HistoricalAwards=false
• 关键词: Influence; diameter; chirality; single; walled

0933484SalehSingle-walled carbon nanotubes (SWNTs) have emerged as high-performance nanomaterials with numerous applications, including electronic, optical, medical, and structural composite technologies. Because of their anticipated role in large-scale industrial production, there is little doubt that SWNTs will ultimately find their way into our aquatic environment. The unusual physicochemical characteristics of SWNTs compared to other nanoparticles -- particularly their very large aspect ratio and complex colloidal behavior (e.g. aggregation) in aqueous solutions -- preclude meaningful theoretical predictions of their colloidal stability and transport behavior. Furthermore, there is a complete lack of fundamental studies on the effects of SWNT structural properties (e.g. diameter and electronic structure) on their fate, transport and biological interactions in aquatic systems. Consequently, there exist no reliable methods to predict the fate and implications of SWNTs in natural aquatic environments based on measurable physical properties of these nanomaterials. The purpose of this proposal is to fundamentally understand the effect of structural properties of SWNTs on their fate and biological behavior in the natural aquatic environment. The study design involves systematic evaluation of aggregation, deposition, organic compound sorption, and uptake/toxicity in fish (Japanese medaka) for semiconductive SWNTs for a range of electronic structures (with consequent variation in diameter and chirality). These studies will be fully novel, as there are no fundamental studies reported in the literature examining the effect of basic structural properties on environmental fate and implications of SWNTs. The research proposed will address the following aims. (1) Fractionation of semiconductive SWNTs by diameter/chirality using density gradient ultracentrifugation; (2) examination of aggregation and deposition kinetics of diameter/chirality-sorted SWNT fractions as a function of organic matter concentration and ionic strength using state-of-the-art dynamic light scattering, quartz crystal microbalance, and conventional column-flow transport experiments; (3) determination of the effect of SWNT diameter/chirality on organic contaminant adsorption using common headspace-partitioning methods; and (4) assessment of the uptake, bio-distribution, and toxic effects of diameter/chirality-sorted SWNTs in Japanese medaka fish after waterborne- or dietary exposure using near-IR fluorescence spectroscopy and microscopy. The proposed research will fill a critical gap in the scientific literature by providing a systematic understanding of the effects of structural properties on SWNT fate, transport and biological behavior. Results of this study may lead to structure-property relations for SWNTs in aquatic environments, allowing a priori predictions of their fate, transport and effects and therefore meets the definition set forth by the NSF for transformative research. The expected research outcomes and benefits include implementation of techniques to systematically separate chiral SWNTs; a complete understanding of the effects of electronic structure on colloidal stability, deposition, and sorptive properties; role of SWNT electronic structure on biological uptake and toxic effects; and finally an increased knowledge-base on the influence of surface structure on the behavior and effects of nanomaterials in the aquatic environment. This increase in basic scientific understanding will ultimately lead to structure-activity relationships from which we may build strategies to assess risks of nanomaterials in the ambient environment, as is currently possible for molecular environmental contaminants. The proposed activity will generate critical knowledge to better understand the environmental implication of a commercially important class of nanomaterial. The majority of requested funds are directed toward the training of doctoral students in an emerging and interdisciplinary research topic. This research will lead to discovery and understanding through teaching and exploration. It provides for student education, mentoring, and research in a novel and highly relevant area that is of immediate and critical importance to our society. This project has potential to involve minority students through student exchange activities with two minority institutions. Dissemination of the research results is planned through conference presentations and peer-reviewed publications.

0933484Saleh 单壁碳纳米管 (SWNT) 已成为具有多种应用的高性能纳米材料，包括电子、光学、医疗和结构复合技术。由于它们在大规模工业生产中的预期作用，毫无疑问，单壁碳纳米管最终将进入我们的水生环境。与其他纳米粒子相比，单壁碳纳米管具有不寻常的物理化学特性，特别是它们在水溶液中的非常大的长宽比和复杂的胶体行为（例如聚集），妨碍了对其胶体稳定性和传输行为进行有意义的理论预测。此外，完全缺乏关于单壁碳纳米管结构特性（例如直径和电子结构）对其在水生系统中的命运、运输和生物相互作用的影响的基础研究。因此，没有可靠的方法可以根据这些纳米材料的可测量物理特性来预测单壁碳纳米管在自然水生环境中的命运和影响。该提案的目的是从根本上了解单壁碳纳米管的结构特性对其在自然水生环境中的命运和生物行为的影响。研究设计涉及对一系列电子结构（随之而来的直径和手性变化）的半导体单壁碳纳米管的聚集、沉积、有机化合物吸附和鱼类（日本青鳉）的吸收/毒性进行系统评估。这些研究将是完全新颖的，因为文献中没有报道检验基本结构特性对环境命运的影响以及单壁碳纳米管的影响的基础研究。拟议的研究将实现以下目标。 (1) 使用密度梯度超速离心按直径/手性对半导体单壁碳纳米管进行分级； (2) 使用最先进的动态光散射、石英晶体微天平和传统的柱流传输实验，检查直径/手性排序的 SWNT 部分的聚集和沉积动力学作为有机物浓度和离子强度的函数; (3) 使用常见的顶空分配方法测定单壁碳纳米管直径/手性对有机污染物吸附的影响； (4) 使用近红外荧光光谱和显微镜评估日本青鳉鱼在水源或饮食暴露后直径/手性排序的单壁碳纳米管的吸收、生物分布和毒性作用。拟议的研究将通过系统地了解结构特性对单壁碳纳米管命运、运输和生物行为的影响，填补科学文献中的一个关键空白。这项研究的结果可能会导致水生环境中单壁碳纳米管的结构-性质关系，从而可以预先预测它们的命运、运输和影响，从而满足 NSF 为变革性研究提出的定义。预期的研究成果和效益包括实施系统分离手性单壁碳纳米管的技术；全面了解电子结构对胶体稳定性、沉积和吸附特性的影响； SWNT电子结构对生物吸收和毒性作用的作用；最后，增加关于表面结构对纳米材料在水生环境中的行为和影响的影响的知识库。基础科学认识的增加最终将导致结构-活性关系，我们可以根据这种关系制定策略来评估周围环境中纳米材料的风险，就像目前对于分子环境污染物而言可能的那样。拟议的活动将产生关键知识，以更好地理解一类具有重要商业意义的纳米材料对环境的影响。大部分申请的资金用于培训博士生的新兴跨学科研究课题。这项研究将通过教学和探索带来发现和理解。它在一个新颖且高度相关的领域提供学生教育、指导和研究，这对我们的社会具有直接和至关重要的意义。该项目有潜力通过与两个少数民族院校的学生交流活动吸引少数民族学生参与。研究成果的传播计划通过会议演讲和同行评审出版物进行。