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Journal of Nanomaterials
Volume 2015, Article ID 127235, 12 pages
Research Article

Impact of Silver and Iron Nanoparticle Exposure on Cholesterol Uptake by Macrophages

1Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
2Cherry Creek High School, Greenwood Village, CO 80111, USA
3Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
4Clemson Nanomaterials Center and COMSET, Clemson University, Anderson, SC 29625, USA

Received 16 June 2015; Revised 8 September 2015; Accepted 9 September 2015

Academic Editor: Abdelwahab Omri

Copyright © 2015 Jonathan H. Shannahan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Macrophages are central to the development of atherosclerosis by absorbing lipids, promoting inflammation, and increasing plaque deposition. Nanoparticles (NPs) are becoming increasingly common in biomedical applications thereby increasing exposure to the immune and vascular systems. This project investigated the influence of NPs on macrophage function and specifically cholesterol uptake. Macrophages were exposed to 20 nm silver NPs (AgNPs), 110 nm AgNPs, or 20 nm Fe3O4 NPs for 2 h and NP uptake, cytotoxicity, and subsequent uptake of fluorescently labeled cholesterol were assessed. Macrophage uptake of NPs did not induce cytotoxicity at concentrations utilized (25 μg/mL); however, macrophage exposure to 20 nm AgNPs reduced subsequent uptake of cholesterol. Further, we assessed the impact of a cholesterol-rich environment on macrophage function following NP exposure. In these sets of experiments, macrophages internalized NPs, exhibited no cytotoxicity, and altered cholesterol uptake. Alterations in the expression of scavenger receptor-B1 following NP exposure, which likely influences cholesterol uptake, were observed. Overall, NPs alter cholesterol uptake, which may have implications in the progression of vascular or immune mediated diseases. Therefore, for the safe development of NPs for biomedical applications, it is necessary to understand their impact on cellular function and biological interactions in underlying disease environments.