Abstract

Carbon nanotubes (CNTs) offer attractive opportunities due to their physical, electrical, mechanical, optical, and thermal properties. They are used in a wide range of applications and are found in numerous consumer products. On the downside, their increasing presence in the environment poses potential threats to living organisms and ecosystems. The aim of this study was to evaluate the toxicity of double-walled carbon nanotubes (DWCNTs) on a new model system: the acellular slime mold Physarum polycephalum. Despite its ecological significance, its simplicity of organization, and its behavioral complexity, exposure of such organisms to nanoparticles has been poorly investigated. Slime molds were exposed to DWCNTs using three routes of exposure (topical, food, environment). We first demonstrated that DWCNTs were rapidly internalized by slime molds especially when DWCNTs were mixed with the food or spread out in the environment. Secondly, we showed that a 6-week exposure to DWCNTs did not lead to bioaccumulation nor did it lead to persistence in the slime molds when they entered a resting stage. Thirdly, we revealed that 2 days following exposure, DWCNTs were almost entirely excreted from the slime molds. Lastly, we uncovered that DWCNTs exposure altered the migration speed, the pseudopods formation, and the expansion rate of the slime molds. Our results extend our current knowledge of CNTs cytotoxicity and introduce P. polycephalum as an ideal organism for nanotoxicology.

摘要

碳纳米管 (CNT) 由于其物理、电学、机械、光学和热特性而提供了有吸引力的机会。它们用于广泛的应用中，并在许多消费品中找到。不利的一面是，它们在环境中越来越多的存在对生物体和生态系统构成了潜在威胁。本研究的目的是评估双壁碳纳米管 (DWCNT) 对新模型系统的毒性：脱细胞粘菌 Physarum polycephalum。尽管具有生态意义、组织的简单性和行为的复杂性，但对此类生物暴露于纳米粒子的研究却很少。使用三种暴露途径（局部、食物、环境）将粘液霉菌暴露于 DWCNT。我们首先证明了 DWCNTs 被粘菌迅速内化，尤其是当 DWCNTs 与食物混合或散布在环境中时。其次，我们表明，接触 DWCNT 6 周不会导致生物积累，也不会导致黏菌进入休眠阶段时在黏菌中持续存在。第三，我们发现暴露后 2 天，DWCNTs 几乎完全从黏菌中排出。最后，我们发现 DWCNTs 暴露改变了迁移速度、伪足形成和粘液霉菌的膨胀率。P. polycephalum作为纳米毒理学的理想生物体。