电化学法测定水中微塑料对典型污染物细胞毒性的影响及机制研究

As emerging pollutants, microplastics have attracted growing attention due to their potential of environmental impacts and ecological risks. It is of great significance to study the toxic effects and mechanism of microplastics and their coexistence with other pollutants. The cell electrochemical method, which is simple, fast, and sensitive, can be used as an effective tool for toxicity detection and evaluation. Therefore, in this study, composite modified electrodes with high catalytic activity toward electroactive substances of cells will be prepared by using novel nanomaterials (such as black phosphorous quantum dots and graphene quantum dots). Electrochemical methods based on the grass carp kidney cells (CIK) and human normal liver cells (L02) will be established to investigate the single and mixture toxicity of microplastics including polystyrene and polyethylene with different particle sizes and concentrations, and typical environmental pollutants including pentachlorophenol, bisphenol A, fluorene and cadmium. Additionally, the effects of microplastics on the cytotoxicity of typical environmental pollutants will be evaluated. Joint toxicity mechanism combing microplastics and typical pollutants will be revealed at cellular level through the analysis by taking many indicators such as cell morphology, oxidative stress and apoptosis into account. This research will provide technical support for in vitro toxicity evaluation of microplastics and typical pollutants, and provide scientific basis for assessment of their combined toxicity and ecological risk.

作为一种新型污染物，微塑料所带来的环境问题和生态风险日益受到关注，研究微塑料及其与污染物共存时的毒性效应及作用机制具有重要意义。细胞电化学方法具有简单、快速、灵敏等特点，可为微塑料及污染物的毒性检测及评价提供有效手段。因此，本项目拟利用新型纳米材料（黑磷量子点、石墨烯量子点等）制备对细胞电活性物质具有高催化活性的复合修饰电极，建立基于草鱼肾脏细胞（CIK）和人正常肝细胞（L02）的电化学测定方法；研究不同粒径和浓度的微塑料（聚乙烯、聚苯乙烯）、典型污染物（五氯酚、双酚A、芴、镉）单一体系及复合体系的细胞毒性效应，评价微塑料对典型污染物细胞毒性的影响；进一步结合细胞形貌、氧化应激、细胞凋亡等多个指标进行综合分析，在细胞水平上揭示微塑料与典型污染物的联合毒性作用机制。本研究可为微塑料及典型污染物体外毒性评价提供技术支撑，为水体微塑料与典型污染物的联合毒性效应及生态风险评价提供科学依据。

新污染物所带来的环境问题和生态风险日益受到关注，研究其本身以及与其他环境污染物共存时的毒性效应及作用机制具有重要意义。针对常规污染物毒性检测方法的不足，发展快速、灵敏、简单的体外毒性检测方法，成为环境污染物早期预警与毒理学评价的迫切需求。本项目以草鱼肾脏细胞（CIK）和人正常肝细胞（L02）为模型，利用新型纳米材料（金纳米粒子、碳纳米角等）制备了对细胞电活性物质具有高催化活性的复合修饰电极，优化检测条件，建立了简单、快速、灵敏的电化学测定方法；利用建立的电化学方法研究了环境污染物（双酚类污染物、抗生素、重金属、氯酚）以及微塑料对细胞活性的影响，发现环境污染物与微塑料的细胞毒性均与其浓度对数之间具有良好的线性关系，基于计算得到的半数抑制浓度（IC50）评价了其毒性作用；研究了几种典型环境污染物与微塑料二元复合体系对细胞的毒性，发现其存在相加作用；结合氧化应激参数和细胞凋亡参数研究了微塑料和典型污染物的细胞毒性作用机制，发现微塑料和典型污染物可导致细胞内活性氧（ROS）含量升高，谷胱甘肽（GSH）含量和超氧化物歧化酶（SOD）活力下降，线粒体膜电位（MMP）降低，DNA损伤加剧，电化学方法测得的微塑料与典型污染物的细胞毒性与氧化应激和细胞凋亡参数之间存在相关性，细胞毒性与ROS、细胞DNA损伤尾距（TM）显著正相关，与GSH、SOD、MMP显著负相关；不同污染物和微塑料二元复合体系的毒性作用机制之间存在差异，双酚A/聚苯乙烯微塑料复合体系对细胞内ROS和GSH的含量影响最为明显，五氯酚/聚苯乙烯微塑料复合体系对细胞内SOD活力和MMP影响最为明显。本研究为环境污染物体外毒性评价提供了技术支撑，为水体微塑料与典型污染物的联合毒性效应及生态风险评价提供了基础数据和科学依据。