The acute toxicity of three differently shaped carbon nanomaterials (CNMs) was studied on Daphnia magna, comparing the induced effects and looking for the toxic mechanisms. We used carbon nano-powder (CNP), with almost spherical primary particle morphology, multi-walled carbon nanotubes (CNTs), tubes of multi-graphitic sheets, and cubic-shaped carbon nanoparticles (CNCs), for which no ecotoxicological data are available so far. Daphnids were exposed to six suspensions (1, 2, 5, 10, 20 and 50 mg L⁻¹) of each CNM, and then microscopically analyzed. Ultrastructural analyses evidenced cellular uptake of nanoparticle in CNP and CNT exposed groups, but not in samples exposed to CNCs. Despite this difference, very similar effects were observed in tissues exposed to the three used CNMs: empty spaces between cells, cell detachment from the basal lamina, many lamellar bodies and autophagy vacuoles. These pathological figures were qualitatively similar among the three groups, but they differed in frequency and severity. CNCs caused the most severe effects, such as partial or complete dissolution of the brush border and thinning of the digestive epithelium. Being the cubic shape not allowed to be internalized into cells, but more effective than others in determining physical damages, we can conclude that shape is an important factor for driving nanoparticle uptake by cells and for determining the acute toxicological endpoints. Shape also plays a key role in determining the kind and the severity of pathologies, which are linked to the physical interactions of CNMs with the exposed tissues.

中文翻译：

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三种不同形状的碳纳米材料对水蚤的比较毒性：是否存在形状效应？

研究了三种不同形状的碳纳米材料（CNMs）对大型蚤（Daphnia magna）的急性毒性，比较了其诱导作用和寻找毒性机理。我们使用的碳纳米粉（CNP）具有几乎球形的初级颗粒形态，多壁碳纳米管（CNT），多石墨片管和立方形碳纳米颗粒（CNC），但尚无生态毒理学数据至今。瑞香鱼暴露于六种悬浮液中（1、2、5、10、20和50 mg L ^-1）的每个CNM，然后进行微观分析。超微结构分析表明，暴露于CNP和CNT的组中细胞吸收了纳米颗粒，而暴露于CNC的样品中却没有。尽管存在这种差异，但在暴露于三种使用过的CNM的组织中观察到了非常相似的效果：细胞之间的空白空间，与基底层的细胞分离，许多层状体和自噬泡。这些病理学数字在三组之间在质上相似，但是在频率和严重性上有所不同。CNC造成最严重的影响，例如刷状缘部分或完全溶解以及消化上皮变薄。不允许将立方形状内化到细胞中，但是在确定物理损伤方面比其他形状更有效，我们可以得出结论，形状是驱动细胞摄取纳米颗粒并确定急性毒理学终点的重要因素。形状在确定病理类型和严重程度方面也起着关键作用，这些病理和严重程度与CNM与裸露组织的物理相互作用有关。