Plastic waste is ubiquitously spread across the world and its smaller analogs—microplastics and nanoplastics—raise particular health concerns. While biological impacts of microplastics and nanoplastics have been actively studied, the chemical and biological bases for the adverse effects are sought after. This work explores contributory factors by combining results from in vitro and model mammalian membrane experimentation to assess the outcome of cell/nanoplastic interactions in molecular detail, inspecting the individual contribution of nanoplastics and different types of protein coronae. The in vitro study showed mild cytotoxicity and cellular uptake of polystyrene (PS) nanoplastics, with no clear trend based on nanoplastic size (20 and 200 nm) or surface charge. In contrast, a nanoplastic size-dependency on bilayer disruption was observed in the model system. This suggests that membrane disruption resulting from direct interaction with PS nanoplastics has little correlation with cytotoxicity. Furthermore, the level of bilayer disruption was found to be limited to the hydrophilic headgroup, indicating that transmembrane diffusion was an unlikely pathway for cellular uptake—endocytosis is the viable mechanism. In rare cases, small PS nanoplastics (20 nm) were found in the vicinity of chromosomes without a nuclear membrane surrounding them; however, this was not observed for larger PS nanoplastics (200 nm). We hypothesize that the nanoplastics can interact with chromosomes prior to nuclear membrane formation. Overall, precoating PS particles with protein coronae reduced the cytotoxicity, irrespective of the corona type. When comparing the two types, the extent of reduction was more apparent with soft than hard corona.

中文翻译：

---

细胞与聚苯乙烯纳米塑料的相互作用——粒径和蛋白质电晕的作用

塑料垃圾无处不在，其较小的类似物——微塑料和纳米塑料——引起了特别的健康问题。虽然微塑料和纳米塑料的生物影响已被积极研究，但其不利影响的化学和生物基础却受到追捧。这项工作通过结合体外和模型哺乳动物膜实验的结果来探索促成因素，以在分子细节上评估细胞/纳米塑料相互作用的结果，检查纳米塑料和不同类型蛋白冠的个体贡献。体外的研究表明聚苯乙烯 (PS) 纳米塑料具有轻微的细胞毒性和细胞吸收，基于纳米塑料尺寸（20 和 200 nm）或表面电荷没有明显的趋势。相反，在模型系统中观察到对双层破坏的纳米塑料尺寸依赖性。这表明与 PS 纳米塑料直接相互作用导致的膜破坏与细胞毒性几乎没有相关性。此外，发现双层破坏水平仅限于亲水性头基，表明跨膜扩散不太可能是细胞摄取的途径——内吞作用是可行的机制。在极少数情况下，在染色体附近发现小的 PS 纳米塑料（20 nm），周围没有核膜；然而，对于较大的 PS 纳米塑料（200 nm）没有观察到这种情况。我们假设纳米塑料可以在核膜形成之前与染色体相互作用。总体而言，无论电晕类型如何，用蛋白质电晕预涂 PS 颗粒都会降低细胞毒性。比较这两种类型时，软电晕的减少程度比硬电晕更明显。