title: Transport of metal oxide nanoparticles and single-walled carbon nanotubes in human mucus.
abstract: Whether mucus layers lining entrance points into the body, including the lung airways, provide protection against the penetration of engineered nanoparticles remains poorly understood. We measured the diffusion coefficients of hundreds of individual nanoparticles of three different metal oxides (nMeOs) and two types of single-walled carbon nanotubes (SWCNTs) in undiluted human mucus. We found that the vast majority of these nanoparticles are efficiently trapped in human mucus and, further, that the mechanism of trapping is adhesive interactions as opposed to steric obstruction. However, a small fraction of zinc oxide (ZnO) nanoparticles moved at rates fast enough to penetrate airway mucus layers. We conclude that human mucus layers probably provide considerable protection for mucosal tissues from the penetration of most nMeOs and SWCNTs, and suggest that further investigation of the potential health risks of exposure to ZnO nanoparticles is warranted.
authors.affiliation: Department of Environmental Health Sciences, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21231, USA.
authors.forename: Ashish
authors.initials: A
authors.lastname: Jachak
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Lai
authors.forename: Kaoru
authors.initials: K
authors.lastname: Hida
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Suk
authors.forename: Nina
authors.initials: N
authors.lastname: Markovic
authors.forename: Shyam
authors.initials: S
authors.lastname: Biswal
authors.forename: Patrick N
authors.initials: PN
authors.lastname: Breysse
authors.forename: Justin
authors.initials: J
authors.lastname: Hanes
mesh_terms: D000328:Adult; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002563:Cerium / Q000493:pharmacokinetics* / Q000633:toxicity; D002582:Cervix Mucus / Q000737:chemistry / Q000378:metabolism*; D004058:Diffusion; D005260:Female; D006801:Humans; D037742:Nanotubes, Carbon; D010316:Particle Size; D015034:Zinc Oxide / Q000493:pharmacokinetics* / Q000633:toxicity; D015040:Zirconium / Q000493:pharmacokinetics* / Q000633:toxicity
chemical_list: D037742:Nanotubes, Carbon; D002563:Cerium; C030583:ceric oxide; D015040:Zirconium; C028541:zirconium oxide; D015034:Zinc Oxide