Distribution of Paramagnetic Fe2O3/SiO2–Core/Shell Nanoparticles in the Rat Lung Studied by Time-of-Flight Secondary Ion Mass Spectrometry: No Indication for Rapid Lipid Adsorption

Nanomaterials

Martin Wiemann¹  Daniel Breitenstein²  Birgit Hagenhoff³  Antje Vennemann⁴  Carsten Engelhard⁵  Lothar Veith⁵ 

[1] Biology, University of Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen, Germany;D Institute for Lung Health gGmbH, Mendelstraße 11, 48149 Münster, Germany;;Department of Chemistry &;IBE R&Tascon GmbH, Mendelstraße 17, 48149 Münster, Germany;

关键词: ToF-SIMS;    dark-field microscopy;    lipid adsorption;    amorphous silica;    core/shell nanoparticles;    lung tissue;    protein corona formation;    nanotoxicology;    rat;   

DOI  :  10.3390/nano8080571

来源: DOAJ

【 摘 要 】

Amorphous silica nanoparticles comprise a class of widely used industrial nanomaterials, which may elicit acute inflammation in the lung. These materials have a large specific surface to which components of the pulmonary micro-milieu can bind. To conduct appropriate binding studies, paramagnetic Fe2O3/SiO2 core/shell nanoparticles (Fe-Si-NP) may be used as an easy-to-isolate silica surrogate, if several prerequisites are fulfilled. To this end, we investigated the distribution of Fe, Si, protein and phosphatidylcholine (PC) by Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) in cryo-sections from the rat lungs to which Fe-Si-NP had been administered for 30 min. Regions-of-interest were identified and analyzed with incident light and enhanced dark-field microscopy (DFM). Fe-Si-NP particles (primary particle size by electron microscopy: 10–20 nm; aggregate size by tracking analysis: 190 ± 20 nm) and agglomerates thereof were mainly attached to alveolar walls and only marginally internalized by cells such as alveolar macrophages. The localization of Fe-Si-NP by DFM was confirmed by ToF-SIMS signals from both, Fe and Si ions. With respect to an optimized signal-to-noise ratio, Fe+, Si+, CH4N+ and the PC head group (C5H15NO4P+) were the most versatile ions to detect iron, silica, protein, and PC, respectively. Largely congruent Fe+ and Si+ signals demonstrated that the silica coating of Fe-Si-NP remained stable under the conditions of the lung. PC, as a major lipid of the pulmonary surfactant, was colocalized with the protein signal alongside alveolar septa, but was not detected on Fe-Si-NP, suggesting that silica nanoparticles do not adsorb lipids of the lung surfactant under native conditions. The study shows that ToF-SIMS is a valuable technique with adequate spatial resolution to analyze nanoparticles together with organic molecules in the lung. The paramagnetic Fe-Si-NP appear well suited to study the binding of proteins to silica nanomaterials in the lung.

【 授权许可】

Unknown