Zhao Jian, Cao Xuesong, Liu Xiaoyu, Wang Zhenyu, Zhang Chenchen, White Jason C, Xing Baoshan
a Institute of Costal Environmental Pollution Control, and Ministry of Education Key Laboratory of Marine Environment and Ecology, Ocean University of China , Qingdao , China .
b Laboratory for Marine Ecology and Environmental Science , Qingdao National Laboratory for Marine Science and Technology, China , Qingdao , China .
Nanotoxicology. 2016 Nov;10(9):1297-305. doi: 10.1080/17435390.2016.1206149. Epub 2016 Jul 15.
The potential adverse effects of CuO nanoparticles (NPs) have increasingly attracted attention. Combining electron microscopic and toxicological investigations, we determined the adhesion, uptake, and toxicity of CuO NPs to eukaryotic alga Chlorella pyrenoidosa. CuO NPs were toxic to C. pyrenoidosa, with a 72 h EC50 of 45.7 mg/L. Scanning electron microscopy showed that CuO NPs were attached onto the surface of the algal cells and interacted with extracellular polymeric substances (EPS) excreted by the organisms. Transmission electron microscopy (TEM) showed that EPS layer of algae was thickened by nearly 4-fold after CuO NPs exposure, suggesting a possible protective mechanism. In spite of the thickening of EPS layer, CuO NPs were still internalized by endocytosis and were stored in algal vacuoles. TEM and electron diffraction analysis confirmed that the internalized CuO NPs were transformed to Cu2O NPs (d-spacing, ∼0.213 nm) with an average size approximately 5 nm. The toxicity investigation demonstrated that severe membrane damage was observed after attachment of CuO NPs with algae. Reactive oxygen species generation and mitochondrial depolarization were also noted upon exposure to CuO NPs. This work provides useful information on understanding the role of NPs-algae physical interactions in nanotoxicity.
氧化铜纳米颗粒（NPs）的潜在不良影响已越来越受到关注。结合电子显微镜和毒理学研究，我们确定了氧化铜纳米颗粒对真核绿藻小球藻的粘附、摄取及毒性。氧化铜纳米颗粒对小球藻有毒性，其72小时半数有效浓度（EC50）为45.7毫克/升。扫描电子显微镜显示，氧化铜纳米颗粒附着在藻类细胞表面，并与生物体分泌的胞外聚合物（EPS）相互作用。透射电子显微镜（TEM）显示，暴露于氧化铜纳米颗粒后，藻类的EPS层增厚了近4倍，这表明可能存在一种保护机制。尽管EPS层增厚，但氧化铜纳米颗粒仍通过内吞作用被内化，并储存在藻类液泡中。透射电子显微镜和电子衍射分析证实，内化的氧化铜纳米颗粒转变为平均尺寸约为5纳米的氧化亚铜纳米颗粒（d间距，约0.213纳米）。毒性研究表明，氧化铜纳米颗粒与藻类附着后，观察到严重的膜损伤。暴露于氧化铜纳米颗粒时还发现了活性氧的产生和线粒体去极化。这项工作为理解纳米颗粒与藻类的物理相互作用在纳米毒性中的作用提供了有用信息。
