Internalization of SiO2 nanoparticles by alveolar macrophages and lung epithelial cells and its modulation by the lung surfactant substitute Curosurf®
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Because of an increasing exposure to environmental and occupational nanoparticles (NPs), the potential risk of these materials for human health should be better assessed. Since one of the main routes of entry of NPs is via the lungs, it is of paramount importance to further characterize their impact on the respiratory system. Here, we have studied the uptake of fluorescently labeled SiO2 NPs (50 and 100 nm) by epithelial cells (NCI-H292) and alveolar macrophages (MHS) in the presence or absence of pulmonary surfactant. The quantification of NP uptake was performed by measuring cell-associated fluorescence using flow cytometry and spectrometric techniques in order to identify the most suitable methodology. Internalization was shown to be time and dose dependent, and differences in terms of uptake were noted between epithelial cells and macrophages. In the light of our observations, we conclude that flow cytometry is a more reliable technique for the study of NP internalization, and importantly, that the hydrophobic fraction of lung surfactant is critical for downregulating NP uptake in both cell types.
KeywordsNCI-H292 Mouse alveolar macrophages Uptake Flow cytometry Microplate reader Brilliant Black Quenching Silica nanoparticles
This study was funded by the E.C. FP7 ENPRA (no. 228789) grant. Support for this study was also provided by Nanotrans (no. EST-2010/2/079) and TiSiTrans (no. PNR-EST-2010/2/79) grants. We acknowledge the confocal microscope platform in the Institute Jacques Monod, Paris, France. Authors would also like to thank to Dr Emmanuel Lopez (Cochin Hospital, Paris) for helping us to obtain the surfactant used in this study.
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