Inactivation, Clearance, and Functional Effects of Lung-Instilled Short and Long Silver Nanowires in Rats.

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.

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Published Version (Please cite this version)

10.1021/acsnano.6b07313

Publication Info

Chung, Kian Fan, Joanna Seiffert, Shu Chen, Ioannis G Theodorou, Angela Erin Goode, Bey Fen Leo, Catriona M McGilvery, Farhana Hussain, et al. (2017). Inactivation, Clearance, and Functional Effects of Lung-Instilled Short and Long Silver Nanowires in Rats. ACS Nano, 11(3). pp. 2652–2664. 10.1021/acsnano.6b07313 Retrieved from https://hdl.handle.net/10161/16013.

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Scholars@Duke

Zhang

Junfeng Zhang

Professor of Global and Environmental Health

Dr. Zhang joined the Duke Faculty in fall 2013 from the University of Southern California where he had been a professor of environmental and global health and the director of Environmental and Biomarkers Analysis Laboratory since 2010. His prior positions include professor, department chair, and associate dean at the Rutgers School of Public Health. Dr. Zhang has more than 290 peer-reviewed publications. His work has been featured in major international media such as the Time, the New York Times, BBC, ABC, CBS, Yahoo News, etc. His early work on characterizing sources of non-methane greenhouse gases made him one of the officially recognized contributor to the 2007 Nobel Peace Prize awarded to IPCC. He is the 2012 recipient of the Jeremy Wesolowski Award, the highest award of the International Society of Exposure Science. He also received a Distinguished Alumni Award from the Rutgers Graduate School.

Dr. Zhang’s research interests include developing novel biomarkers of human exposure and health effects, assessing health and climate co-benefits of air pollution interventions, and examining biological mechanisms by which environmental exposures exert adverse health effects. Dr. Zhang has led a number of international collaborations to study air pollution health effects and underlying pathophysiologic mechanisms. These studies integrate epidemiological and toxicological approaches into natural experiment designs. He has conducted several indoor air purification intervention studies to evaluate the effectiveness of personal exposure reduction in improving health outcomes in China. Currently, he is conducting intervention trials of residential air purification in older adults with a heart disease history and adults at risk for Type 2 diabetes living in Los Angels where air pollution levels are high. He is co-leading a project to study whether and how particulate matter pollution affects respiratory viral infections in two cities of Mongolia. 


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