Cellulose nanofibers (CNFs) are an emerging engineered nanomaterial that are utilized in a variety of applications, including as a replacement for urea-formaldehyde, and other adhesives, as the binding agent in manufactured fiber and particle boards. To ensure the health and well-being of those producing, installing, or otherwise using cellulose nanofiber boards (CNFBs) it is imperative that the particulate matter (PM) produced during CNFB manipulation be evaluated for toxicity. We developed and internally verified a generation system to examine the PM produced by sanding CNFB using aluminum oxide sandpaper. With 80-grit sandpaper our system produced a low dispersity aerosol, as determined by a scanning mobility particle sizer and an optical particle counter, with a geometric mean of 28 nm (GSD = 1.60). ICP-MS evaluation showed little difference in metal concentrations between CNFB PM and nonsanded CNFB stock. We then used the system to simultaneously generate and expose both male and female C57BL/6J mice acutely for 4 hours at a concentration of 7.9 mg/m3. Sham-exposed controls were treated similarly but without sanding the CNFB. Analysis of bronchoalveolar lavage (BAL) fluid biomarkers showed no signs of inflammatory response at either 4- or 24-hours post exposure. Further, BAL cell viability, number of total cells, and pulmonary cellular recruitment were not significantly changed between the sham-exposed controls and CNFB-exposed mice. Histology further confirmed no pulmonary toxicity as a result of CNFB PM inhalation. We conclude that inhalation of a high concentration of the PM from manipulation of a CNFB did not produce acute toxic responses within 24 hours of exposure.

中文翻译：

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纤维素纳米纤维板职业相关颗粒物的急性体内肺毒性评估


纤维素纳米纤维 (CNF) 是一种新兴的工程纳米材料，可用于多种应用，包括作为脲醛和其他粘合剂的替代品，作为人造纤维和刨花板中的粘合剂。为了确保生产、安装或以其他方式使用纤维素纳米纤维板 (CNFB) 的人员的健康和福祉，必须对 CNFB 操作过程中产生的颗粒物 (PM) 进行毒性评估。我们开发并内部验证了一个生成系统，用于检查使用氧化铝砂纸打磨 CNFB 时产生的 PM。我们的系统使用 80 粒度的砂纸产生了低分散性气溶胶，由扫描迁移率粒度仪和光学粒子计数器测定，几何平均值为 28 nm (GSD = 1.60)。 ICP-MS 评估显示 CNFB PM 和未打磨的 CNFB 库存之间的金属浓度几乎没有差异。然后，我们使用该系统同时生成雄性和雌性 C57BL/6J 小鼠，并以 7.9 mg/m3 的浓度急性暴露 4 小时。假暴露对照进行类似处理，但不打磨 CNFB。支气管肺泡灌洗 (BAL) 液体生物标志物分析显示，暴露后 4 小时或 24 小时均未出现炎症反应迹象。此外，假暴露对照组和 CNFB 暴露小鼠之间，BAL 细胞活力、细胞总数和肺细胞募集没有显着变化。组织学进一步证实吸入 CNFB PM 不会导致肺部毒性。我们的结论是，通过操作 CNFB 吸入高浓度 PM，在暴露后 24 小时内不会产生急性毒性反应。