College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.
College of Electronic Engineering and Automation, Shandong University of Science and Technology, Qingdao 266590, China.
J Hazard Mater. 2022 Apr 5;427:127872. doi: 10.1016/j.jhazmat.2021.127872. Epub 2021 Nov 27.
Airborne nanoplastics can be inhaled to threaten human health, but research on the inhaled nanoplastic toxicity is in its infancy, and interaction mechanisms are largely unknown. By means of molecular dynamics simulation, we employed spherical nanoplastics of different materials and aging properties to predict and elucidate nanoplastic transformations in alveolar fluid and impacts on the lung surfactant (LS) film at the alveolar air-water interface. Results showed spontaneous adsorption of LS molecules on nanoplastics of 10 nm in diameter, and the adsorption layer can be defined as coronas, which increased the particle size, reduced and equalized the surface hydrophobicity, and endowed nanoplastics with negative surface charges. Nanoplastics of polypropylene and polyvinylchloride materials were dissolved by LS, which could increase bioavailability of polymers and toxic additives. Aging properties represented by the nanoplastic size, polymer's molecular weight and surface chemistry altered nanoplastic transformations through modulating competition between polymer-LS and polymer-polymer interactions. Upon transferred to the alveolar air-water interface through vesicle fusion, nanoplastics could interfere with the normal biophysical function of LS through disrupting the LS ultrastructure and fluidity, and prompting collapse of the LS film. These results provide new molecular level insights into fate and toxicity of airborne nanoplastics in human respiratory system.
空气中的纳米塑料可被吸入，从而威胁人类健康，但关于吸入纳米塑料毒性的研究还处于起步阶段，其相互作用机制在很大程度上尚不清楚。本研究采用分子动力学模拟的方法，选用不同材料和老化特性的球形纳米塑料，预测并阐明了纳米塑料在肺泡液中的转化，以及在肺泡气-液界面处对肺表面活性剂（LS）膜的影响。结果表明，LS 分子会自发地吸附在直径为 10nm 的纳米塑料上，吸附层可以定义为冠，这增加了颗粒尺寸，降低并均化了表面疏水性，并使纳米塑料带负电荷。LS 可溶解聚丙稀和聚氯乙烯材料的纳米塑料，这可能会增加聚合物和有毒添加剂的生物利用度。老化特性（如纳米塑料的尺寸、聚合物的分子量和表面化学）通过调节聚合物-LS 和聚合物-聚合物相互作用之间的竞争，改变纳米塑料的转化。通过囊泡融合转移到肺泡气-液界面后，纳米塑料可能通过破坏 LS 的超微结构和流动性，以及促使 LS 膜坍塌，从而干扰 LS 的正常生物物理功能。这些结果为空气中纳米塑料在人体呼吸系统中的归宿和毒性提供了新的分子水平认识。
