Similar toxicity mechanisms between graphene oxide and oxidized multi-walled carbon nanotubes in Microcystis aeruginosa
Similar toxicity mechanisms between graphene oxide and oxidized multi-walled carbon nanotubes in Microcystis aeruginosa
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DOI：
10.1016/j.chemosphere.2020.129137
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发表时间：
2021-02-01
期刊：
影响因子：
8.8
通讯作者：
Perreault, Francois
中科院分区：
文献类型：
--
作者：
Cruces, Edgardo;Barrios, Ana C.;Perreault, Francois
在光合微生物中，碳纳米材料（CNM）的毒性通常表现为生长、活力、光合作用的下降以及氧化应激的诱导。然而，目前尚不清楚 CNM 中的碳结构形状，例如与二维氧化石墨烯 (GO) 相比的一维碳纳米管 (CNT)，如何影响它们与细胞相互作用的方式。在本研究中，比较了 GO 和氧化多壁碳纳米管在蓝藻铜绿微囊藻中的作用，以确定两种 CNM 如何与蓝藻相互作用并诱导蓝藻毒性的相似或差异。利用叶绿素 a 浓度的变化，发现 GO 和 CNT 在 96 小时诱导 50% 抑制 (EC50) 的有效浓度分别为 11.1 μg/mL 和 7.38 μg/mL。两种 CNM 的 EC50 未发现有统计学差异。在 EC50 浓度下测量的荧光素二乙酸酯和 2',7'-二氯二氢荧光素二乙酸酯荧光的变化表明酯酶活性降低，但没有氧化应激。扫描和透射电子显微镜成像没有显示暴露于 GO 或 CNT 的细胞中存在广泛的膜损伤。总而言之，在没有氧化应激或膜损伤的情况下代谢活性和光合活性的降低支持了这样的假设：GO 和 CNT 都通过与遮光和细胞聚集相关的物理机制诱导间接毒性。这种间接毒性解释了为什么 CNT 和 GO 之间形状、尺寸和表面性质的内在差异并未导致它们对蓝藻产生毒性的方式存在差异。 (C) 2020 Elsevier Ltd. 保留所有权利。
In photosynthetic microorganisms, the toxicity of carbon nanomaterials (CNMs) is typically characterized by a decrease in growth, viability, photosynthesis, as well as the induction of oxidative stress. However, it is currently unclear how the shape of the carbon structure in CNMs, such as in the 1-dimensional carbon nanotubes (CNTs) compared to the two-dimensional graphene oxide (GO), affects the way they interact with cells. In this study, the effects of GO and oxidized multi-walled CNTs were compared in the cyanobacterium Microcystis aeruginosa to determine the similarities or differences in how the two CNMs interact with and induce toxicity to cyanobacteria. Using change in Chlorophyll a concentrations, the effective concentrations inducing 50% inhibition (EC50) at 96 h are found to be 11.1 mu g/mL and 7.38 mu g/mL for GO and CNTs, respectively. The EC50 of the two CNMs were not found to be statistically different. Changes in fluorescein diacetate and 2',7'-dichlorodihydrofluorescein diacetate fluorescence, measured at the EC50 concentrations, suggest a decrease in esterase enzyme activity but no oxidative stress. Scanning and transmission electron microscopy imaging did not show extensive membrane damage in cells exposed to GO or CNTs. Altogether, the decrease in metabolic activity and photosynthetic activity without oxidative stress or membrane damage support the hypothesis that both GO and CNTs induced indirect toxicity through physical mechanisms associated with light shading and cell aggregation. This indirect toxicity explains why the intrinsic differences in shape, size, and surface properties between CNTs and GO did not result in differences in how they induce toxicity to cyanobacteria. (C) 2020 Elsevier Ltd. All rights reserved.