School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science and Technology, Nanjing, 210044, PR China.
Institute of Environmental Sciences (CML), Leiden University, PO Box 9518, 2300 RA, Leiden, the Netherlands.
Chemosphere. 2021 Aug;276:130015. doi: 10.1016/j.chemosphere.2021.130015. Epub 2021 Feb 20.
Novel products often have a multitude of nanomaterials embedded; likewise within many products graphite-based products are decorated with nano-zirconium oxide (nZrO) because graphene is an ultrahigh conductive material whereas nZrO is for instance fire-retardant. As a consequence, the pristine/isolated nanoparticle has unique beneficial properties but it is no longer the only compound that needs to be considered in risk assessment. Data on joint toxicological implications are particularly important for the hazard assessment of multicomponent nanomaterials. Here, we investigated the mechanisms underlying the cytotoxicity induced by the co-occurrence of nZrO and two graphene nanomaterials including graphene nanoplatelets (GNPs) and reduced graphene oxide (RGO) to the freshwater algae Chlorella pyrenoidosa. Exposure to GNPs and/or RGO induced enhanced cytotoxicity of nZrO to the algae. Intracellular oxidative stress and cellular membrane functional changes in C. pyrenoidosa were the reason for the enhancement of toxicity induced by the binary mixtures of GNPs/RGO and nZrO. Furthermore, mitochondria-generated ROS played a major role in regulating the treatment-induced cellular response in the algae. Observations of cellular superficial- and ultra-structures indicated that the binary mixtures provoked oxidative damage to the algal cells. RGO increased the cytotoxicity and the extent of cellular oxidative stress to a higher extent than GNPs. These findings provide new insights that are of use in the risk assessment of mixtures of graphene-based carbon nanomaterials and other ENPs, and fit the new ideas on product testing that respects the combination effects.
新型产品通常嵌入了多种纳米材料；同样，在许多产品中，基于石墨的产品都用纳米氧化锆（nZrO）进行了装饰，因为石墨烯是一种超高导电材料，而 nZrO 则具有例如阻燃性。因此，原始/分离的纳米颗粒具有独特的有益特性，但它不再是风险评估中唯一需要考虑的化合物。关于联合毒理学影响的数据对于多组分纳米材料的危害评估尤其重要。在这里，我们研究了 nZrO 与两种石墨烯纳米材料（包括石墨烯纳米片（GNPs）和还原氧化石墨烯（RGO））共存时诱导淡水藻类栅藻细胞毒性的机制。暴露于 GNPs 和/或 RGO 会增强 nZrO 对藻类的细胞毒性。栅藻细胞内氧化应激和细胞膜功能的变化是导致 GNPs/RGO 和 nZrO 二元混合物毒性增强的原因。此外，线粒体产生的 ROS 在调节藻类的治疗诱导细胞反应中起主要作用。对细胞表面和超微结构的观察表明，二元混合物会引发藻类细胞的氧化损伤。RGO 比 GNPs 更能增加细胞毒性和细胞氧化应激的程度。这些发现为基于石墨烯的碳纳米材料和其他 ENPs 混合物的风险评估提供了新的见解，并符合尊重组合效应的新产品测试新理念。
