Health Effects Laboratory Division , National Institute for Occupational Safety and Health , Morgantown , West Virginia 26505 , United States.
ACS Nano. 2018 Mar 27;12(3):2292-2310. doi: 10.1021/acsnano.7b07281. Epub 2018 Feb 22.
Organomodified nanoclays (ONCs) are increasingly used as filler materials to improve nanocomposite strength, wettability, flammability, and durability. However, pulmonary risks associated with exposure along their chemical lifecycle are unknown. This study's objective was to compare pre- and post-incinerated forms of uncoated and organomodified nanoclays for potential pulmonary inflammation, toxicity, and systemic blood response. Mice were exposed via aspiration to low (30 μg) and high (300 μg) doses of preincinerated uncoated montmorillonite nanoclay (CloisNa), ONC (Clois30B), their respective incinerated forms (I-CloisNa and I-Clois30B), and crystalline silica (CS). Lung and blood tissues were collected at days 1, 7, and 28 to compare toxicity and inflammation indices. Well-dispersed CloisNa caused a robust inflammatory response characterized by neutrophils, macrophages, and particle-laden granulomas. Alternatively, Clois30B, I-Clois30B, and CS high-dose exposures elicited a low grade, persistent inflammatory response. High-dose Clois30B exposure exhibited moderate increases in lung damage markers and a delayed macrophage recruitment cytokine signature peaking at day 7 followed by a fibrotic tissue signature at day 28, similar to CloisNa. I-CloisNa exhibited acute, transient inflammation with quick recovery. Conversely, high-dose I-Clois30B caused a weak initial inflammatory signal but showed comparable pro-inflammatory signaling to CS at day 28. The data demonstrate that ONC pulmonary toxicity and inflammatory potential relies on coating presence and incineration status in that coated and incinerated nanoclay exhibited less inflammation and granuloma formation than pristine montmorillonite. High doses of both pre- and post-incinerated ONC, with different surface morphologies, may harbor potential pulmonary health hazards over long-term occupational exposures.
有机改性纳米粘土（ONC）越来越多地被用作填充材料，以提高纳米复合材料的强度、润湿性、可燃性和耐久性。然而，其化学生命周期中与暴露相关的肺部风险尚不清楚。本研究的目的是比较未煅烧和有机改性纳米粘土的预煅烧和煅烧形式，以评估其潜在的肺部炎症、毒性和全身血液反应。通过吸入的方式，将小鼠暴露于低（30μg）和高（300μg）剂量的预煅烧未涂层蒙脱石纳米粘土（CloisNa）、ONC（Clois30B）、它们各自的煅烧形式（I-CloisNa 和 I-Clois30B）和结晶二氧化硅（CS）中。在第 1、7 和 28 天收集肺和血液组织，以比较毒性和炎症指数。分散良好的 CloisNa 引起了强烈的炎症反应，表现为中性粒细胞、巨噬细胞和载有颗粒的肉芽肿。相反，Clois30B、I-Clois30B 和 CS 高剂量暴露引起低度、持续的炎症反应。Clois30B 高剂量暴露表现出中等程度的肺损伤标志物增加，以及在第 7 天达到峰值的巨噬细胞募集细胞因子特征，随后在第 28 天出现纤维化组织特征，与 CloisNa 相似。I-CloisNa 表现出急性、短暂的炎症，恢复迅速。相反，高剂量的 I-Clois30B 引起的初始炎症信号较弱，但在第 28 天与 CS 表现出相似的促炎信号。数据表明，ONC 的肺部毒性和炎症潜力取决于涂层的存在和煅烧状态，即涂层和煅烧纳米粘土比原始蒙脱石表现出更少的炎症和肉芽肿形成。具有不同表面形态的预煅烧和后煅烧 ONC 的高剂量，可能在长期职业暴露中对肺部健康构成潜在危害。
