在自然环境中，污染物大多以混合物形式存在，进入生物体后通常会产生联合毒理效应。石墨烯纳米材料具有优良的吸附性能，进入环境后容易与其它污染物发生相互作用，进而影响这些污染物的环境行为。磷酸三苯酯（triphenyl phosphate, TPP）是一种有机磷酸酯类阻燃剂，分子中含有多个苯环，容易与石墨烯发生相互作用。随着石墨烯和TPP需求量和生产量的日益增加，有必要研究石墨烯和TPP的联合毒理效应，为生态风险评价提供理论依据和数据支持。
本研究首先采用电化学和光谱学方法，研究石墨烯和TPP能否进入细胞膜及其与p53-DNA（p53基因启动子区域DNA片段）发生作用的机理。然后以紫贻贝（Mytilus galloprovincialis）为研究对象，通过组织切片技术、抗氧化酶活性检测和实时荧光定量PCR技术（qRT-PCR）研究石墨烯和TPP对紫贻贝的单独和联合毒理效应。主要研究结果如下：
（1）石墨烯和TPP均可以导致磷脂双层膜修饰金电极的阻抗降低，说明两者均可以破坏模拟生物膜的完整性。石墨烯和TPP同时存在时表现出协同作用，使模拟生物膜受到的破坏程度增大。
（2）石墨烯可以通过嵌插作用和沟槽作用与p53-DNA结合，进而改变其构象并影响其双螺旋结构的稳定性。TPP可以通过沟槽作用与p53-DNA结合，但两者相互作用较弱。石墨烯和TPP同时存在时表现出协同作用，TPP可以促进石墨烯与p53-DNA的结合。
（3）石墨烯暴露导致紫贻贝的鳃组织和消化腺组织产生轻微的损伤，而TPP暴露则未产生明显损伤，两者联合暴露时组织损伤程度与石墨烯单独暴露时没有明显变化。石墨烯和TPP均可促进紫贻贝消化腺组织内活性氧（ROS）水平升高并对部分抗氧化酶活性有抑制作用，两者联合暴露时则表现出拮抗作用，使组织内ROS水平降低。石墨烯和TPP均可导致紫贻贝组织中与免疫应激反应、细胞骨架、信号转导等功能相关基因的表达量发生变化，但两者联合暴露时表现出拮抗作用。此外，TPP暴露可以显著抑制生殖相关基因的表达，说明TPP对紫贻贝具有生殖毒性，但石墨烯暴露和联合暴露则没有显著影响。
（4）综合以上结果表明，石墨烯和TPP可以协同破坏并穿过细胞膜，并且协同与DNA发生作用，但进入紫贻贝体内后，在氧化应激和基因表达水平上表现出拮抗作用。

In the natural environment, organisms are frequently exposed to complex mixtures of pollutants. These pollutants usually enter organisms simultaneously, which leads to joint toxicological effect. With excellent adsorption properties, graphene nanomaterials can interact with other pollutants when they are released into the environment, which may affect the environmental behavior of these pollutants. The molecule structure of triphenyl phosphate (TPP) contains three benzene rings, which leads to that TPP interact with graphene easily. With the mass demand and production of graphene and TPP, it is of great significance to study the joint toxicological effects of graphene and TPP, which will provide theoretical basis and data support for ecological risk assessment.
In this study, electrochemical methods were used to study the effect of graphene and TPP on the cell membrane, and spectroscopic methods were used to study the interaction of graphene and TPP with the promoter region segment of p53 gene (p53-DNA). Techniques of tissue sections, antioxidant enzyme activities assay and real-time quantitative reverse transcription PCR (qRT-PCR) were applied to study the individual and combined toxicological effects of graphene and TPP on mussel Mytilus galloprovincialis. The main results were as follows:
(1) Both graphene and TPP led to a significant decrease in the impedance of the gold electrode modified by the phospholipid bilayer membrane, indicating that both of them had a certain effect on the integrity of the biomembrane. With the combined effects of graphene and TPP, the damage of simulated biomembrane was increased, which showed a synergistic effect.
(2) Graphene could be combined with p53-DNA through intercalation and groove action, which might change the conformation of p53-DNA and affect the stability of p53-DNA. TPP could be combined with p53-DNA through groove action, but the interaction force was weaker compared with graphene. Graphene and TPP had a synergistic effect when they existed simultaneously, and TPP might promote the combination of graphene and p53-DNA.
(3) Graphene exposure caused slight damage to the gill and digestive gland tissues of mussel M. galloprovincialis, while TPP exposure did not cause significant damage. Both graphene and TPP induced oxidative stress in digestive gland tissues and had inhibitory effects on some antioxidant enzymes, while combined exposure reduced the oxidative stress, showing a certain antagonism. Both graphene and TPP could cause significant changes in expression of genes associated with immune response, stress response, cytoskeleton and signal transduction in digestive gland tissues of M. galloprovincialis, while combined exposure was antagonistic about gene expression. In addition, TPP exposure led to significant changes in the expression of genes associated with reproduction, indicating that TPP had a certain reproductive toxicity, while graphene exposure and joint exposure had no significant effect on it.
(4) These above results showed that graphene and TPP might destroy and enter the cell membrane and interacted with DNA synergistically, but there was an antagonistic effect on the level of oxidative stress and gene expression when they enter mussel.