Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany.
BG University Hospital Bergmannsheil, Surgical Research, Ruhr University Bochum, Bochum, Germany.
Sci Total Environ. 2021 May 15;769:144575. doi: 10.1016/j.scitotenv.2020.144575. Epub 2021 Jan 9.
Silica fibers with a dimension of 0.3 μm ∙ 3.2 μm nm were prepared by a modified Stöber synthesis as model particles. The particles were characterized by scanning electron microscopy, elemental analysis, thermogravimetry and X-ray powder diffraction. Their uptake by macrophages (THP-1 cells and NR8383 cells) was studied by confocal laser scanning microscopy and scanning electron microscopy. The uptake by cells was very high, but the silica fibers were not harmful to NR8383 cells in concentrations up to 100 μg mL. Only above 100 μg mL, significant cell toxic effects were observed, probably induced by a high dose of particles that had sedimented on the cells and led to the adverse effects. The chemotactic response as assessed by the particle-induced migration assay (PICMA) was weak in comparison to a control of agglomerated silica particles. The as-prepared fibers were fully X-ray amorphous but crystallized to β-cristobalite after heating to 1000 °C and converted to α-cristobalite upon cooling to ambient temperature. The fibers had sintered to larger aggregates but retained their elongated primary shape. The particle cytotoxicity towards THP-1 cells was not significantly enhanced by the crystallization.
尺寸为 0.3μm×3.2μm 的二氧化硅纤维采用改进的 Stöber 合成法制备而成，用作模型颗粒。通过扫描电子显微镜、元素分析、热重分析和 X 射线粉末衍射对颗粒进行了表征。通过共聚焦激光扫描显微镜和扫描电子显微镜研究了巨噬细胞（THP-1 细胞和 NR8383 细胞）对这些颗粒的摄取。细胞的摄取非常高，但在高达 100μg/mL 的浓度下，二氧化硅纤维对 NR8383 细胞没有危害。仅在 100μg/mL 以上，才观察到明显的细胞毒性作用，这可能是由沉降在细胞上的高剂量颗粒引起的，从而导致了不良反应。与团聚二氧化硅颗粒的对照相比，用颗粒诱导的迁移测定（PICMA）评估的趋化反应较弱。所制备的纤维完全是非晶态的，但在加热至 1000°C 时结晶为β-方石英，并在冷却至环境温度时转化为α-方石英。纤维烧结成较大的聚集体，但保留了其拉长的原始形状。结晶对 THP-1 细胞的细胞毒性没有显著增强。
