二维纳米材料的理化性质与其环境行为和微生物毒性的相关性研究

As graphene-like two-dimensional (2D) nanomaterials have entered industrial production and daily life, they will be destined to impair the ecological environment and human health in the near future. The up-to-date studies are only regarding a single kind of 2D nanomaterials, which is not sufficient to establish the relationship of material properties to environmental behavior and toxicological effect. Therefore, graphene, 2D molybdenum disulfide, and 2D black phosphorus, which possess similar structure, diverse property, and wide prospect of application, are selected in this project as representative 2D nanomaterials. We will focus on both qualitative and quantitative investigations of sorption behavior of humic acid on the 2D nanomaterials, the microbial toxicity of 2D nanomaterials, and the effect of humic acid on the environmental behavior, including suspension, agglomeration, and dissociation, and on the microbial toxicity of 2D nanomaterials. Meanwhile, the correlation between the physiochemical properties of 2D nanomaterials and their environmental behavior and microbial toxicity will be constructed, which will provide a feasible approach for the environmental risk assessment and safty application of 2D nanomaterials. The results will also be guidance for the regulation of biotoxicity and reduce the environmental exposure and ecological risk of 2D nanomaterials.

以石墨烯为代表的二维纳米材料已经进入人们的生产和生活，在未来数年内极有可能对生态环境和人体健康造成一定影响。现有的研究仅仅针对单一种类二维纳米材料，不足以建立材料性质与其环境行为和毒性效应的关系规律。因此，本项目拟选取结构相似、性质不同且应用前景广阔的石墨烯、层状二硫化钼和层状黑磷为典型二维纳米材料，定性及定量研究腐殖酸在典型二维纳米材料上的吸附行为和机理，典型二维纳米材料的微生物毒性及机制，以及腐殖酸吸附对典型二维纳米材料悬浮、团聚、解离等环境行为和微生物毒性的影响机制。同时，建立理化性质与二维纳米材料环境行为和微生物毒性间的构效关系，为二维纳米材料的环境风险评估和选择性安全应用提供理论依据和技术支撑，对调控二维纳米材料的生物毒性，降低环境暴露和生态风险具有指导意义。

二维纳米材料的需求量和产量不断提高，它们将不可避免地进入环境，对生态环境和人体健康造成潜在影响。本项目选取结构相似、性质不同且应用前景广阔的石墨烯（graphene）、层状二硫化钼（MoS2）和层状黑磷（LBP）为典型二维纳米材料，研究它们与腐殖酸（HA）的相互作用，微生物毒性效应，腐殖酸对二维纳米材料环境行为及微生物毒性的影响机制，为二维纳米材料的生态风险评估和安全应用提供理论依据和技术支持。结果表明，HA通过Π-Π作用、疏水作用等吸附在二维纳米材料表面，能够提高二维纳米材料在水溶液中的分散稳定性。LBP通过提高细菌的抗氧化能力，促进蛋白质合成和分泌，以及上调三羧酸循环和甲硫氨酸代谢相关通路，选择性促进肠致病性大肠杆菌（EPEC）的生长。此外，HA吸附提高了graphene对B. tropicus的细菌毒性。Graphene对呼吸链破坏作用强，影响ATP合成酶功能，使ATP产量降低，导致合成代谢紊乱，呼吸链损坏的同时伴随着ROS的积累。而graphene-HA复合物处理组细菌呼吸链在蛋白和转录水平的变化不大，但膜损伤、脂质过氧化程度严重，这主要是由于HA吸附改变了石墨烯的能带结构，使复合物导带位置与生物氧化还原电位重合，细菌内生物分子与graphene-HA复合物发生电子转移，使生物分子被氧化，导致细菌死亡。LBP对土壤酶活和微生物群落结构的影响有土壤HA含量有关。