Carbon nanotubes and nanofibers (CNT/F) have known toxicity but simultaneous comparative studies of the broad material class, especially those with a larger diameter, with computational analyses linking toxicity to their fundamental material characteristics was lacking. It was unclear if all CNT/F confer similar toxicity, in particular, genotoxicity. Nine CNT/F (MW #1–7 and CNF #1–2), commonly found in exposure assessment studies of U.S. facilities, were evaluated with reported diameters ranging from 6 to 150 nm. All materials were extensively characterized to include distributions of physical dimensions and prevalence of bundled agglomerates. Human bronchial epithelial cells were exposed to the nine CNT/F (0–24 μg/ml) to determine cell viability, inflammation, cellular oxidative stress, micronuclei formation, and DNA double-strand breakage. Computational modeling was used to understand various permutations of physicochemical characteristics and toxicity outcomes. Analyses of the CNT/F physicochemical characteristics illustrate that using detailed distributions of physical dimensions provided a more consistent grouping of CNT/F compared to using particle dimension means alone. In fact, analysis of binning of nominal tube physical dimensions alone produced a similar grouping as all characterization parameters together. All materials induced epithelial cell toxicity and micronuclei formation within the dose range tested. Cellular oxidative stress, DNA double strand breaks, and micronuclei formation consistently clustered together and with larger physical CNT/F dimensions and agglomerate characteristics but were distinct from inflammatory protein changes. Larger nominal tube diameters, greater lengths, and bundled agglomerate characteristics were associated with greater severity of effect. The portion of tubes with greater nominal length and larger diameters within a sample was not the majority in number, meaning a smaller percentage of tubes with these characteristics was sufficient to increase toxicity. Many of the traditional physicochemical characteristics including surface area, density, impurities, and dustiness did not cluster with the toxicity outcomes. Distributions of physical dimensions provided more consistent grouping of CNT/F with respect to toxicity outcomes compared to means only. All CNT/F induced some level of genotoxicity in human epithelial cells. The severity of toxicity was dependent on the sample containing a proportion of tubes with greater nominal lengths and diameters.

中文翻译：

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美国工厂使用或生产的各类碳纳米管和纳米纤维的物理化学特性和遗传毒性


碳纳米管和纳米纤维 (CNT/F) 具有已知的毒性，但缺乏对广泛材料类别（尤其是直径较大的材料）的同步比较研究，以及将毒性与其基本材料特性联系起来的计算分析。目前尚不清楚是否所有 CNT/F 都具有相似的毒性，特别是遗传毒性。在美国设施的暴露评估研究中常见的 9 种 CNT/F（MW #1-7 和 CNF #1-2）经过评估，报告的直径范围为 6 至 150 nm。所有材料都经过广泛的表征，包括物理尺寸的分布和成束团聚物的普遍性。将人支气管上皮细胞暴露于九种 CNT/F (0–24 μg/ml) 中，以确定细胞活力、炎症、细胞氧化应激、微核形成和 DNA 双链断裂。计算模型用于了解理化特征和毒性结果的各种排列。 CNT/F 物理化学特性的分析表明，与单独使用颗粒尺寸平均值相比，使用物理尺寸的详细分布提供了更一致的 CNT/F 分组。事实上，仅对标称管物理尺寸的分箱分析就产生了与所有特征参数在一起类似的分组。所有材料在测试的剂量范围内都会诱导上皮细胞毒性和微核形成。细胞氧化应激、DNA 双链断裂和微核形成始终聚集在一起，并具有较大的物理 CNT/F 尺寸和团聚体特征，但与炎症蛋白变化不同。 较大的标称管直径、较长的长度和成束的附聚物特征与较大的影响严重程度相关。样品中具有较大标称长度和较大直径的管部分在数量上并不占多数，这意味着具有这些特征的管的较小百分比就足以增加毒性。许多传统的物理化学特性，包括表面积、密度、杂质和粉尘，与毒性结果并不相关。与仅平均值相比，物理尺寸的分布在毒性结果方面提供了更一致的 CNT/F 分组。所有 CNT/F 都会在人上皮细胞中诱导一定程度的遗传毒性。毒性的严重程度取决于样品中含有较大标称长度和直径的管的比例。