Design of Safer Carbon-Based Nanomaterials: The Impact of Surface Modifications on Toxicity and Environmental Fate and Transport

提案题目：设计更安全的碳基纳米材料：表面修饰对毒性和环境命运和运输的影响。首席研究员：Julie Zimmerman机构：耶鲁大学提案号：CBET- 0854373该奖项由2009年美国复苏和再投资法案（公法111-5）资助。本研究的目的是发展对设计降低对人类健康和环境风险的碳纳米管所必需的基本认识。支持这一目标的知识将通过对表征良好的原始和功能化碳纳米管（单壁碳纳米管，SWCNTs）和多壁碳纳米管（MWCNTs）的生物毒性测试来收集。然后对改性后的碳纳米管在代表性环境条件下的稳定性进行评估，对在环境条件下发生转化的碳纳米管的毒性特性进行重新评估。完成拟议的工作将涉及以下任务：(i)碳纳米管的合成，（ii）碳纳米管的表面功能化，（iii）碳纳米管的表征，（iv）碳纳米管生物毒性的评价，(v)碳纳米管在水生系统中的环境转化的表征，（vi）碳纳米管的聚集，（vii）分析由环境条件引起的变化对毒性的影响，以及（viii）考虑政策影响。他们将合成定义良好的SWCNTs和MWCNTs。除了测试原始碳纳米管外，他们还将测试一系列功能化，从而获得具有增强溶解度和极性范围的碳纳米管。这些包括氨基、羟基、羧基、磺酸盐、烷基和吡咯烷基功能化碳纳米管，以及氟化SWCNTs，这是迄今为止已知的最密集的功能化碳纳米管。仔细表征合成和功能化的碳纳米管对于从生物毒性研究中得出有意义的结论至关重要。他们将使用先进的表征工具来获得有关碳纳米管纯度和物理和化学性质的信息，包括拉曼，FTIR和近红外荧光光谱；TEM， TGA和zeta电位测量。然后，他们将测试原始和功能化碳纳米管的生物毒性，以深入了解碳纳米管的化学和物理性质对其毒性的作用。一旦释放到水生环境中，功能化的碳纳米管将发生化学和物理转化。他们将研究在环境条件下化学功能化的稳定性以及这些转化对碳纳米管生物毒性的影响。最后，将讨论这些结果对设计更安全碳纳米管的政策的影响。本研究的结果将提供以下方面的信息：(i)碳纳米管的表面修饰导致毒性降低或无毒性，以及（ii）这些修饰在长期保护人类健康和环境的环境条件下的稳定性。最终，这些信息将用于设计下一代碳纳米管。目前的研究表明，如果将本项目所侧重的问题类型纳入课程，在科学和工程课程和专业中征聘和保留妇女和代表性不足的群体的可能性就会增加。预计耶鲁大学也将出现类似的趋势，该校已经是全美工科本科女生比例最高的大学。虽然这个项目将为本科生和研究生提供研究机会，并与耶鲁大学现有的课程相结合，但他们也为扩大这个项目的影响做出了独特和创新的贡献。和耶鲁的教职员工以及相关学生一起？在美国皮博迪自然历史博物馆，项目团队将致力于为7-12年级的学校课程开发适合年龄的可持续发展模块，其中包括绿色产品设计和环保制造的内容。通过这些经验，这些学生将更好地理解设计和开发符合环境、经济和社会目标的产品和过程所面临的挑战，以及消费者在系统中的角色。

Proposal Title: Design of Safer Carbon-Based Nanomaterials: The Impact of Surface Modifications on Toxicity and Environmental Fate and TransportPrincipal Investigator: Julie Zimmerman Institution: Yale UniversityProposal No: CBET- 0854373This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The objective of this study is to develop the fundamental understanding necessary to design carbon nanotubes with reduced risk to human health and the environment. Knowledge to support this goal will be gathered through biotoxicity testing of well-characterized pristine and functionalized carbon nanotubes, both single-walled carbon nanotubes, SWCNTs, and multi-walled carbon nanotubes, MWCNTs. The modified CNTs will then be evaluated for stability under representative environmental conditions, and those CNTs that undergo a transformation in environmental conditions will be reevaluated for toxic characteristics. Completion of the proposed work will involve the following tasks: (i) synthesis of CNTs, (ii) surface functionalization of CNTs, (iii) characterization of CNTs, (iv) evaluation of CNT biotoxicity, (v) characterization of environmental transformations of CNTs in aquatic systems, (vi) aggregation of CNTs, (vii) analysis of the impacts of changes resulting from environmental conditions on toxicity, and (viii) consideration of policy implications. They will synthesize well-defined SWCNTs and MWCNTs. In addition to the testing of pristine CNTs, they will test a range of functionalizations that result in CNTs with enhanced solubility and a range of polarities. These include amino, hydroxyl, carboxy, sulfonate, alkyl, and pyrrolidinyl functionalized CNTs, as well as fluorinated SWCNTs, the most densely functionalized CNTs known to date. Careful characterization of the synthesized and functionalized CNTs is critical for the formation of meaningful conclusions from the biotoxicity studies. They will use advanced characterization tools to obtain information about the CNT purity and physical and chemical properties, including Raman, FTIR, and Near IR fluorescence spectroscopy; TEM, TGA, and zeta potential measurement. They will then test the biotoxicity of the pristine and functionalized CNTs to gain insights into the role of CNT chemical and physical properties on their toxicity. Once released into the aquatic environment, functionalized CNTs will undergo chemical and physical transformations. They will investigate the stability of the chemical functionalizations under environmental conditions and the impact of these transformations on CNT biotoxicity. Finally, the implications of the results for policies regarding the design of safer CNTs will be discussed. The results from this study will provide information on (i) surface modifications to CNTs that result in reduced or no toxicity, and (ii) the stability of these modifications in environmental conditions for long-term protection of human health and the environment. Ultimately, the information will be used to design the next generation of CNTs. Current research demonstrates the potential for an increase in the recruitment and retention of women and underrepresented groups in science and engineering courses and majors when the type of issues this project is focused on are introduced into the curriculum. It is anticipated that similar trends will be observed at Yale University, which already graduates the highest percentage of female undergraduate engineering students in the country. While this project will serve as a source of research opportunities for undergraduate and graduate students as well as be integrated into existing courses at Yale, they also have a unique and innovative contribution to broaden the impacts of this project. Together with staff and associated students at Yale?s Peabody Museum of Natural History, the project team will be working to develop an age appropriate module for their School Programs for grades 7-12 on sustainability to include components on green product design and environmentally benign manufacturing. Through this experience, these students would gain a better understanding of the challenges associated with designing and developing products and processes that meet environmental, economic, and social goals as well as the role of consumers in the system.