Nano-plastics (NPs), defined as particles smaller than 1 µm, have emerged as a significant environmental contaminant due to their potential ecological impacts. This study explores the size-dependent dynamics and tissue-specific distribution of polystyrene nano-plastics (PS-NPs) in Danio rerio exposed to PS-NPs at an environmentally relevant concentration of 1 μg/mL for 28 days, followed by a 17-day depuration period. PS-NPs of 20, 100, 200, and 500 nm were assessed in the intestine, liver, gills, muscle, and brain using transmission electron microscopy (TEM) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Smaller PS-NPs (20 nm) showed the highest accumulation in the intestine, followed by the liver, and gills, due to their greater surface area and cellular penetration. In contrast, larger PS-NPs (500 nm) exhibited lower accumulation and clearance rates, especially in the brain, suggesting restricted passage through biological barriers. The intestine consistently had the highest concentrations in both accumulation and depuration, while the brain maintained the lowest across all nanoparticle sizes. During depuration, smaller particles cleared more quickly, whereas larger particles persisted. This study highlights the tissue-specific distribution and retention patterns of PS-NPs in D. rerio, providing insights into nanoparticle behavior in aquatic organisms and the need for long-term size-specific environmental risk assessments.

中文翻译：

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Danio rerio 中纳米塑料的尺寸依赖性动力学和组织特异性分布：积累和净化


纳米塑料 （NP） 定义为小于 1 μm 的颗粒，由于其潜在的生态影响，已成为一种重要的环境污染物。本研究探讨了聚苯乙烯纳米塑料 （PS-NPs） 在暴露于 1 μg/mL 环境相关浓度的 PS-NPs 28 天，然后是 17 天的净化期的 Danio rerio 中的大小依赖性动力学和组织特异性分布。使用透射电子显微镜 （TEM） 和基质辅助激光解吸/电离飞行时间质谱 （MALDI-TOF-MS） 评估肠道、肝脏、鳃、肌肉和大脑中 20 、 100 、 200 和 500 nm 的 PS-NPs。较小的 PS-NPs （20 nm） 在肠道中的积累最高，其次是肝脏和鳃，因为它们的表面积和细胞渗透性更大。相比之下，较大的 PS-NPs （500 nm） 表现出较低的积累和清除率，尤其是在大脑中，表明通过生物屏障的通道受限。肠道在积累和净化方面的浓度始终最高，而大脑在所有纳米颗粒尺寸中保持最低浓度。在净化过程中，较小的颗粒清除得更快，而较大的颗粒则持续存在。本研究强调了 P-NPs 在 D. rerio 中的组织特异性分布和保留模式，为水生生物中的纳米颗粒行为以及长期尺寸特异性环境风险评估的必要性提供了见解。