Using ciliates to understand the environmental fate and impact of carbon nanotubes

碳纳米管（CNT）是一种有望给许多行业带来革命的纳米颗粒。它们完全由碳组成，就像钻石一样，但它们被制造成直径在1到25纳米之间、长度可变的微小管。碳纳米管有几个特殊的性质，如机械强度，建议应用在不同的领域。碳纳米管是否会对环境造成危害尚不清楚，但值得关注的是，因为没有细胞或有机体进化出这些结构。需要开发评估碳纳米管及其废物对人类健康和生态系统影响的方法，这是本提案的重点。我们建议研究碳纳米管与一组单细胞生物，纤毛虫之间的相互作用。纤毛虫被归类为原生动物或原生动物，在世界各地的水和土壤中都有发现。它们是食物网中细菌和多细胞生物之间的重要纽带。纤毛虫在经济上也很重要：它们存在于污水处理厂，在那里它们的作用是产生高质量的污水。纤毛虫可以被认为是处理颗粒的专家，因为它们不断地将水和细菌吞没到食物液泡中。碳纳米管可以作为单独的纳米管存在，也可以作为聚集体存在。从毒理学的角度来看，单个纳米管的毒性可能比聚集体大得多。碳纳米管聚集可以被视为一种解毒机制，但也是它们通过食物链进入人类的途径。因此，我们将研究碳纳米管在土壤和水中的聚集以及纤毛虫在其中的作用，以及纤毛虫加入碳纳米管是否会调节碳纳米管在食物网中的转移。了解这些过程可以引导最小化碳纳米管的释放和环境影响的方法，监测环境中的碳纳米管，并进行补救。这项研究的一个特别令人兴奋和有益的副产品可能是开发使用纤毛虫和碳纳米管来监测环境中化学污染物的方法。

Carbon nanotubes (CNT) are nanoparticles that promise to revolutionize many industries. They are composed entirely of carbon, like diamond, but they are manufactured to be tiny tubes with diameters of 1 to 25 nm and with variable lengths. CNT have several exceptional properties, such as mechanical strength, that suggest applications in diverse fields. Whether CNT will be an environmental hazard is unknown but is of concern because no cell or organism evolved with these structures. Methods of evaluating the impact of CNT and their waste on the health of humans and ecosystems need to be developed and is the focus of this proposal. We are proposing to study the interactions between CNT and a group of single cell organisms, the ciliates. Ciliates are classified as protozoa or protista and are found in the waters and soils of the world. They are an important link between bacteria and multicellular organisms in food webs. Ciliates are also of economic importance: they are found in sewage treatment plants, where they function to produce good quality sewage effluent. Ciliates can be considered specialists at dealing with particles because they are constantly engulfing water and bacteria into food vacuoles. CNT can exist as individual nanotubes and as aggregates. From a toxicological point of view, the single nanotubes are likely much more toxic than aggregates. CNT aggregation can be viewed as a detoxifying mechanism, but also as a route for them to move through food chains and into humans. Therefore, we will investigate the aggregation of CNT in soil and water and the role of ciliates in this and whether the incorporation of CNT by ciliates modulates CNT transfer up food webs. Understanding these processes can lead to ways of minimizing the release and environmental impact of CNT, of monitoring CNT in the environment, and of undertaking remediation. A particularly exciting and beneficial spin off of this research could be the development of methods that use ciliates and CNT to monitor chemical contaminants in the environment.