Efficient Internalization and Intracellular Translocation of Inhaled Gold Nanoparticles in Rat Alveolar Macrophages

Abstract

Aim: To investigate the relationship of alveolar macrophages and inhaled nanoparticles (NPs) in the lung. Materials & methods: Rats were exposed by inhalation to 16-nm gold NPs for 6 h, and ultramicroscopic observation on the frequency and localization of gold NPs within lavaged macrophages was performed for 7 days. Results & discussion: The majority of macrophages examined on day 0 (94%) contained internalized gold NPs, and the percentage decreased to 59% on day 7. Gold NPs were exclusively found within cytoplasmic vesicles. On day 0, most gold NPs appeared to be individual or slightly agglomerated, while they were frequently agglomerated on day 7. Conclusion: Alveolar macrophages efficiently internalized NPs by endocytosis, and rearrangements of vesicles and of NPs in the vesicles of macrophages occurred.

Keywords::

• alveolar macrophage
• cellular trafficking
• gold
• inhalation
• internalization
• nanoparticle

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Acknowledgements

We would like to thank X Hecht from the Technical University of Munich (Department of Technical Chemistry II, Munich, Germany) for performing the Brunauer, Emmett and Teller surface area measurements, and P Valceschini (BASF, Ludwigshafen, Germany) for the ultrastructural analysis. We also would like to thank A Rosenauer and M Schowalter, (Department of Physics, University of Bremen, Germany) for the energy dispersive technology analysis of transmission electron microscopy samples.

Additional information

Funding

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.