title: Solution-engineered palladium nanoparticles: model for health effect studies of automotive particulate pollution.
abstract: Palladium (Pd) nanoparticles are recognized as components of airborne automotive pollution produced by abrasion of catalyst materials in the car exhaust system. Here we produced dispersions of hydrophilic spherical Pd nanoparticles (Pd-NP) of uniform shape and size (10.4 ± 2.7 nm) in one step by Bradley's reaction (solvothermal decomposition in an alcohol or ketone solvent) as a model particle for experimental studies of the Pd particles in air pollution. The same approach provided mixtures of Pd-NP and nanoparticles of non-redox-active metal oxides, such as Al(2)O(3). Particle aggregation in applied media was studied by DLS and nanoparticle tracking analysis. The putative health effects of the produced Pd nanoparticles and nanocomposite mixtures were evaluated in vitro, using human primary bronchial epithelial cells (PBEC) and a human alveolar carcinoma cell line (A549). Viability of these cells was tracked by vital dye exclusion, and apoptosis was also assessed. In addition, we monitored the release of IL-8 and PGE(2) in response to noncytotoxic doses of the nanoparticles. Our studies demonstrate cellular uptake of Pd nanoparticles only in PBEC, as determined by TEM, with pronounced and dose-dependent effects on cellular secretion of soluble biomarkers in both cell types and a decreased responsiveness of human epithelial cells to the pro-inflammatory cytokine TNF-α. When cells were incubated with higher doses of the Pd nanoparticles, apoptosis induction and caspase activation were apparent in PBEC but not in A549 cells. These studies demonstrate the feasibility of using engineered Pd nanoparticles to assess the health effects of airborne automotive pollution.
authors.affiliation: Department of Chemistry, Biocenter, Swedish University of Agricultural Sciences (SLU), Box 7015, SE-75007, Uppsala, Sweden.
authors.forename: Kai E
authors.initials: KE
authors.lastname: Wilkinson
authors.forename: Lena
authors.initials: L
authors.lastname: Palmberg
authors.forename: Erika
authors.initials: E
authors.lastname: Witasp
authors.forename: Maciej
authors.initials: M
authors.lastname: Kupczyk
authors.forename: Neus
authors.initials: N
authors.lastname: Feliu
authors.forename: Per
authors.initials: P
authors.lastname: Gerde
authors.forename: Gulaim A
authors.initials: GA
authors.lastname: Seisenbaeva
authors.forename: Bengt
authors.initials: B
authors.lastname: Fadeel
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Dahlén
authors.forename: Vadim G
authors.initials: VG
authors.lastname: Kessler
mesh_terms: D001692:Biological Transport; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004738:Engineering / Q000379:methods*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006262:Health; D006801:Humans; D053768:Metal Nanoparticles; D008954:Models, Biological; D010165:Palladium / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity*; D012996:Solutions; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D052638:Particulate Matter; D012996:Solutions; D001335:Vehicle Emissions; D010165:Palladium