ROCKWOOL International A/S, Hovedgaden 584, 2640 Hedehusene, Denmark.
ROCKWOOL International A/S, Hovedgaden 584, 2640 Hedehusene, Denmark.
Toxicol In Vitro. 2022 Feb;78:105270. doi: 10.1016/j.tiv.2021.105270. Epub 2021 Oct 30.
The biopersistence of fiber materials is one of the cornerstones in estimating potential risk to human health upon inhalation. To connect epidemiological and in vivo investigations with in vitro studies, reliable and robust methods of fiber biopersistence determination and understanding of fiber dissolution mechanism are required. We investigated dissolution properties of oil treated stone wool fibers with and without sugar-based binder (SBB) at 37 °C in the liquids representing macrophages intracellular conditions (pH 4.5). Conditions varied from batch to flow of different rates. Fiber morphology and surface chemistry changes caused by dissolution were monitored with scanning electron microscopy and time-of-flight secondary ion mass spectrometry mapping. Stone wool fiber dissolution rate depends on liquid composition (presence of ligands, such as citrate), pH, reaction products transport and fibers wetting properties. The dissolution rate decreases when: 1) citrate is consumed by the reaction with the released Al cations; 2) the pH increases during a reaction in poorly buffered solutions; 3) the dissolution products are accumulated; 4) fibers are not fully wetted with the fluid. Presence of SBB has no influence on dissolution rate if fiber material was wetted prior to dissolution experiment to avoid poorly wetted fiber agglomerates formation in the synthetic lung fluids.
纤维材料的生物持久性是评估吸入对人类健康潜在风险的基石之一。为了将流行病学和体内研究与体外研究联系起来，需要可靠和稳健的纤维生物持久性测定方法和纤维溶解机制的理解。我们研究了在代表巨噬细胞细胞内条件的液体（pH 4.5）中，37°C 下有无糖基结合剂（SBB）的油处理石棉纤维的溶解特性。条件从批处理到不同速率的流动变化。通过扫描电子显微镜和飞行时间二次离子质谱映射监测溶解引起的纤维形态和表面化学变化。石棉纤维的溶解速率取决于液体成分（配体如柠檬酸盐的存在）、pH 值、反应产物的传输和纤维的润湿性能。当以下情况发生时，溶解速率会降低：1）释放的 Al 阳离子与柠檬酸反应消耗了柠檬酸；2）在缓冲能力差的溶液中反应时 pH 值升高；3）溶解产物积累；4）纤维未被液体完全润湿。如果在溶解实验前将纤维材料润湿，以避免在合成肺液中形成润湿不良的纤维团聚体，则 SBB 的存在对溶解速率没有影响。
