The increase in industrial production of multi-walled carbon nanotubes (MWCNTs) raises concerns about their potential adverse effects associated to environmental releases, especially in aquatic environments where they are likely to accumulate. This study focuses on the environmental impact of MWCNTs, specifically on a benthic freshwater diatom (), which plays a major role in the primary production of water bodies. The obtained results indicate that exposure to MWCNTs in the presence of natural organic matter (NOM) inhibits diatom's growth in a dose-dependent manner after 72 h of exposure. Interestingly, the photosystem II quantum yield (PSII) in diatoms remains unaffected even after exposure to MWCNTs at 10 mg/L. After 48 h of exposure, MWCNTs are found to bind preferentially to extracellular polymeric substances (EPS) produced by diatoms, which could decrease their toxicity by limiting their interaction with this organism. However, measurement of genotoxicity and teratogenicity in diatoms exposed to MWCNTs revealed that the exposure to MWCNTs increased the occurrence of cells with micronuclei and abnormal frustules. Microscopy analyses including two-photon excitation microscopy (TPEM) revealed the internalization of MWCNTs. Investigations of the diatom's frustule structure using Scanning electron microscopy (SEM) indicated that the presence of pore structures constitutes a pathway allowing MWCNTs uptake. The presence in the diatom's cytoplasm of MWCNTs might possibly induce disturbances of the cellular components, leading to the observed genotoxic and teratogenic effects. In view of previous studies, this work underscores the need for further studies on the interaction between nanomaterials and different diatom species, given the species-specific nature of the interactions.

中文翻译：

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细胞摄取多壁碳纳米管与淡水硅藻线性菱形藻的遗传毒性和致畸作用相关


多壁碳纳米管（MWCNT）工业生产的增加引起了人们对其环境释放的潜在不利影响的担忧，特别是在它们可能积累的水生环境中。这项研究的重点是多壁碳纳米管对环境的影响，特别是底栖淡水硅藻（），它在水体的初级生产中发挥着重要作用。所得结果表明，在存在天然有机物（NOM）的情况下暴露于多壁碳纳米管，暴露72小时后，硅藻的生长会以剂量依赖的方式受到抑制。有趣的是，即使暴露于 10 mg/L 的多壁碳纳米管后，硅藻的光系统 II 量子产率 (PSII) 仍然不受影响。暴露 48 小时后，发现多壁碳纳米管优先与硅藻产生的胞外聚合物 (EPS) 结合，这可以通过限制其与硅藻的相互作用来降低其毒性。然而，对暴露于多壁碳纳米管的硅藻的遗传毒性和致畸性的测量表明，暴露于多壁碳纳米管增加了具有微核和异常硅藻的细胞的发生。包括双光子激发显微镜 (TPEM) 在内的显微镜分析揭示了 MWCNT 的内化。使用扫描电子显微镜 (SEM) 对硅藻壳结构的研究表明，孔结构的存在构成了允许 MWCNT 吸收的途径。硅藻细胞质中多壁碳纳米管的存在可能会引起细胞成分的紊乱，从而导致观察到的遗传毒性和致畸效应。 鉴于以前的研究，鉴于相互作用的物种特异性，这项工作强调需要进一步研究纳米材料和不同硅藻物种之间的相互作用。