As the prevalence of plastic micro- and nanoparticles in the environment, foods, and beverages continues to increase, the risk of human exposure to and uptake of such particles, notably via ingestion or inhalation, is also elevated. Despite this development, relatively little is known about the potential adverse effects of plastic particles on humans. The lack of relevant plastic nanoparticles for use in studies investigating their behavior and effect on human cells is a key hurdle that must be overcome prior to generating hazard data. We herein demonstrate the creation of fluorescent nanoparticles of the thermoplastic polymers poly(ethylene terephthalate), polypropylene, and polystyrene. The particles were produced by melt-processing and milling. The analysis of scanning electron microscopy images showed core diameters of less than 75 nm. Furthermore, the images revealed that the milled particles had highly heterogeneous shapes, as is often seen in environmental samples. The particles were exposed to relevant cell lines (i.e. Caco-2 intestinal epithelial cells and J774A.1 macrophages) to determine their uptake, assessed by confocal laser microscopy, and biocompatibility, assessed by measuring the release of lactate dehydrogenase. Exposure data showed no cytotoxicity at the concentrations utilized in this study. Interaction of the particles was found to be cell type dependent, with agglomeration on the apical surface and few intracellular particles in the intestinal epithelial cells in comparison to numerous internalized particles in the macrophages. In conclusion, the herein presented melt-processing and milling methods resulted in heterogeneously shaped plastic nanoparticles with a fluorescence label allowing their behavior within a complex biological environment to be studied.

中文翻译：

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荧光塑料纳米粒子可追踪其在生理环境中的相互作用和命运

随着塑料微粒和纳米颗粒在环境，食物和饮料中的流行不断增加，人体尤其是通过这种方式接触和摄取此类颗粒的风险摄入或吸入也会升高。尽管有这种发展，但对于塑料颗粒对人类的潜在不利影响知之甚少。缺乏用于研究其行为和对人类细胞影响的研究的相关塑料纳米颗粒是在生成危害数据之前必须克服的关键障碍。我们在本文中证明了热塑性聚合物聚对苯二甲酸乙二酯，聚丙烯和聚苯乙烯的荧光纳米粒子的产生。通过熔融加工和研磨来生产颗粒。扫描电子显微镜图像的分析显示芯直径小于75nm。此外，图像显示研磨的颗粒具有高度不均匀的形状，这在环境样品中经常看到。颗粒暴露于相关的细胞系（即的Caco-2肠上皮细胞和巨噬细胞J774A.1），以确定它们的摄取，通过激光共聚焦显微镜评价，和生物相容性，通过测量乳酸脱氢酶的释放评估。暴露数据表明，在本研究中使用的浓度下无细胞毒性。发现颗粒的相互作用是细胞类型依赖性的，与巨噬细胞中的许多内在化颗粒相比，其在顶表面上附聚并且在肠上皮细胞中几乎没有细胞内颗粒。总而言之，本文提出的熔融加工和研磨方法导致具有荧光标记的异形塑料纳米颗粒，从而使其在复杂的生物环境中的行为得以研究。