Inactivation, clearance, and functional effects of lung-instilled short and long silver nanowires in rats
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
There is a potential for silver nanowires (AgNWs) to be inhaled, but there is little information on their health effects and their chemical transformation inside the lungs in vivo. We studied the effects of short (S-AgNWs; 1.5 μm) and long (L-AgNWs; 10 μm) nanowires instilled into the lungs of Sprague–Dawley rats. S- and L-AgNWs were phagocytosed and degraded by macrophages; there was no frustrated phagocytosis. Interestingly, both AgNWs were internalized in alveolar epithelial cells, with precipitation of Ag2S on their surface as secondary Ag2S nanoparticles. Quantitative serial block face three-dimensional scanning electron microscopy showed a small, but significant, reduction of NW lengths inside alveolar epithelial cells. AgNWs were also present in the lung subpleural space where L-AgNWs exposure resulted in more Ag+ve macrophages situated within the pleura and subpleural alveoli, compared with the S-AgNWs exposure. For both AgNWs, there was lung inflammation at day 1, disappearing by day 21, but in bronchoalveolar lavage fluid (BALF), L-AgNWs caused a delayed neutrophilic and macrophagic inflammation, while S-AgNWs caused only acute transient neutrophilia. Surfactant protein D (SP-D) levels in BALF increased after S- and L-AgNWs exposure at day 7. L-AgNWs induced MIP-1α and S-AgNWs induced IL-18 at day 1. Large airway bronchial responsiveness to acetylcholine increased following L-AgNWs, but not S-AgNWs, exposure. The attenuated response to AgNW instillation may be due to silver inactivation after precipitation of Ag2S with limited dissolution. Our findings have important consequences for the safety of silver-based technologies to human health.
Date Issued
2017-03-28
Date Acceptance
2017-02-21
Citation
ACS Nano, 2017, 11 (3), pp.2652-2664
ISSN
1936-086X
Publisher
American Chemical Society
Start Page
2652
End Page
2664
Journal / Book Title
ACS Nano
Volume
11
Issue
3
Copyright Statement
© 2017 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)
Sponsor
Natural Environment Research Council (NERC)
Commission of the European Communities
Grant Number
NE/H012893/1
ERC-2010-StG-20091028
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Multidisciplinary
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
silver nanowires
alveolar epithelial cells
macrophages
silver sulfidation
surfactant protein D
bronchial hyperresponsiveness
CARBON NANOTUBES
PARTICLE-SIZE
IN-VIVO
INFLAMMATION
NANOPARTICLES
EXPOSURE
TRANSPARENT
SULFIDATION
INHALATION
MICROSCOPY
alveolar epithelial cells
bronchial hyperresponsiveness
macrophages
silver nanowires
silver sulfidation
surfactant protein D
Animals
Instillation, Drug
Lung
Nanowires
Rats
Rats, Sprague-Dawley
Silver
Lung
Animals
Rats
Rats, Sprague-Dawley
Silver
Instillation, Drug
Nanowires
Nanoscience & Nanotechnology
Publication Status
Published
Date Publish Online
2017-02-21