Polystyrene nanoparticles (PS-NPs) derived from both environmental and occupational sources are an important class of ultrafine particles associated with human pulmonary disorders. The effects of surface charges of particle internalization and toxicity to alveolar cells, especially under conditions comparable to those found during breathing, have not been examined. Here, we applied cyclic stretches (CS) to human alveolar cells during nanoparticle exposure and show an enhanced accumulation of positively charged polystyrene nanoparticles as compared to similar negatively charged particles. The cellular uptake of the positive particles into live cells was visualized with three-dimensional optical diffraction tomography (3-D ODT). The simultaneous application of both periodic stretching as well as positively charged nanoparticles led to blebbing morphology and activation of apoptotic signaling compared to control cells. Our findings provide a better understanding of how surface charge mediates the uptake and toxicity of nanoplastics under the dynamical mechanical conditions relevant for breathing exposures.

中文翻译：

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在循环拉伸下，肺泡细胞中塑料纳米颗粒的表面电荷依赖性细胞毒性。

源自环境和职业来源的聚苯乙烯纳米颗粒（PS-NP）是与人类肺部疾病相关的一类重要的超细颗粒。尚未检查颗粒内在化和对肺泡细胞毒性的表面电荷的影响，尤其是在与呼吸期间可比的条件下。在这里，我们在纳米粒子暴露过程中将循环拉伸（CS）应用于人的肺泡细胞，并显示出与类似的带负电粒子相比，带正电的聚苯乙烯纳米粒子的积聚增强。用三维光学衍射层析成像（3-D ODT）可视化阳性颗粒进入活细胞的细胞摄取。与对照细胞相比，同时施加周期性拉伸以及带正电的纳米粒子会导致起泡形态和凋亡信号传导的激活。我们的发现更好地了解了在与呼吸接触有关的动态机械条件下，表面电荷如何介导纳米塑料的吸收和毒性。