C60 Biotransformation and Bioaccumulation: Environmental Impact Implications

快速的工业规模生产，加上独特的材料性能，支持工程纳米级材料无意中影响自然系统的健康和功能的日益关注。 基于碳的纳米级材料，例如富勒烯和纳米管，已经被提出用于各种应用，并且有望以工业规模生产。 对自然和工程系统中的材料行为建立基本的定量理解，可以建立准确的预测行为模型，这对于风险缓解和可持续性所需的材料生命周期评估至关重要。 特别令人感兴趣的是生物界面，这些材料可以相互作用，因为生物介导的富勒烯转化可以显着影响其流动性，生物利用度，反应性，毒性和整体环境影响。 然而，迄今为止，还没有进行富勒烯生物转化的系统评价。 他们将寻求评估水溶性富勒烯物种对生化转化的敏感性及其生物学意义。具体而言，它们将：（1）通过使用放射性标记的P14 PCB 60 B部分表征生物转化的速率和副产物，（2）确定生物转化如何影响CB 60 B的毒性，以及（3）通过模型分析系统量化P14 PCB 60 B及其副产物的生物利用度和生物累积潜力。 他们将测试以下假设：1）CB 60 B可以被非特异性酶系统氧化，例如锰过氧化物酶，其参与通过自由基（OH）攻击的复杂碳大分子降解，和/或被由纤维素分解真菌或细菌产生的降解柠檬酸盐化合物的其他酶氧化;（2）这种生物转化将降低CB 60 B的毒性和生物累积潜力，但可能增加其溶解度和生物利用度。 使用具有不同同位素特征的化学独特CB 60 B，将使用无细胞（例如，催化非特异性自由基（OH）氧化的纯化锰过氧化物酶）和全细胞、纤维素分解真菌的体内培养物、PAH降解混合培养物和PAH降解纯培养物进行生物转化研究。 反应动力学和产物将通过一系列分析（放射性色谱法（HPLC）、P13 PC-NMR、MALDI-MS、UV/维斯、闪烁计数等）进行表征。 相应的毒性研究将测量暴露于水可利用的CB 60 B和生物转化衍生物之前和之后的微生物异养活性。 C60和相应衍生物的生物累积性和可得性将通过整个生物体（模型吸附系统）和仿生吸附剂实验进行评价，这些实验与以前对多环芳烃进行的研究类似。这项工作响应了来自环境倡导组织，新兴纳米技术行业和监管机构的关于纳米颗粒在环境中行为的可靠数据的要求。 了解生物转化如何影响工程纳米材料在环境中的行为，对于确保纳米技术在不超过支持它们的生态能力的情况下改善材料和社会条件非常重要。 此外，该项目的学生将获得宝贵的跨学科和合作经验与纳米化学和环境工程的应用。 这个项目将加强国家？在一个合格的研究人员短缺的新兴需求领域，将有助于纳米技术的发展，作为一种可持续发展的工具，而不是作为一种环境责任。

CBET- 0829158 AlvarezRapid industrial scale production, coupled with unique material properties, underpin rising concerns of engineered nano-scale materials inadvertently impacting the health and function of natural systems. Carbon based nano-scale materials such as fullerenes and nanotubes in particular have been proposed for a variety of applications and are on track to be produced at industrial scales. Building a fundamental, quantitative understanding of material behavior in natural and engineered systems allows for accurate predictive behavior models which are critical for material life cycle assessment(s) necessary for risk mitigation and sustainability. Of particular interest is the biological interface at which these materials may interact as biologically mediated transformations of fullerenes could significantly influence their mobility, bioavailability, reactivity, toxicity and overall environmental impact. Yet, to date, no systematic evaluations of fullerene biotransformation has been conducted. They will seek to evaluate the susceptibility of aqueous available fullerene species to biochemical transformations and their biological significance. Specifically, they will: (1) characterize the rates and byproducts of biotransformation through, in part, the use of radio labeled P14PCB60B, (2) determine how biotransformation affects the toxicity of CB60B, and (3) quantify the bioavailability and bioaccumulation potential of P14PCB60B and its byproducts through model earthworm systems. They will test the hypotheses that: 1) CB60B can be oxidized by non-specific enzyme systems such as manganese peroxidase, which is involved in complex carbon macromolecules degradation via radical (OH) attack, and/or by other enzymes produced by cellulytic fungi or bacteria that degrade recalcitrant compounds; and (2) such biotransformations will decrease the toxicity and bioaccumulation potential of CB60B, but may increase its solubility and bioavailability. Using chemically unique CB60B with differential isotopic signatures, biotransformation investigations will be conducted with cell free (e.g. purified manganese peroxidase which catalyzes non-specific radical (OH) oxidation), and with whole cell, in vivo cultures of cellulytic fungi, PAH-degrading mixed cultures, and PAH-degrading pure cultures. Reaction kinetics and products will be characterized by a battery of analyses (Radiochromatography (HPLC), P13PC-NMR, MALDI-MS, UV/Vis, Scintillation Counting, among others). Corresponding toxicity studies will measure microbial heterotrophic activity before and after exposure to water available CB60B and bio-transformed derivatives. Bioaccumulation and availability of both C60 and corresponding derivatives will be evaluated through whole organism (model earthworm systems) and biomimetic sorbent experiments similar to previous studies done with polyaromatic hydrocarbons. This work responds to calls for reliable data on nanoparticle behavior in the environment that have come from environmental advocacy groups, the emerging nanotechnology industry and the regulatory community. Understanding how biotransformation affects the behavior of engineered nanomaterials in the environment is important to ensure that nanotechnology improves material and social conditions without exceeding the ecological capabilities that support them. Furthermore, students on this project will gain valuable interdisciplinary and collaborative experience with applications of nanochemistry and environmental engineering. This project will strengthen the nation?s research and human resource base in an emerging need area where qualified researchers are in short supply, and will contribute to the development of nanotechnology as a tool for sustainability rather than as an environmental liability.