title: The responses of immune cells to iron oxide nanoparticles.
abstract: Immune cells play an important role in recognizing and removing foreign objects, such as nanoparticles. Among various parameters, surface coatings of nanoparticles are the first contact with biological system, which critically affect nanoparticle interactions. Here, surface coating effects on nanoparticle cellular uptake, toxicity and ability to trigger immune response were evaluated on a human monocyte cell line using iron oxide nanoparticles. The cells were treated with nanoparticles of three types of coatings (negatively charged polyacrylic acid, positively charged polyethylenimine and neutral polyethylene glycol). The cells were treated at various nanoparticle concentrations (5, 10, 20, 30, 50 μg ml(-1) or 2, 4, 8, 12, 20 μg cm(-2)) with 6 h incubation or treated at a nanoparticle concentration of 50 μg ml(-1) (20 μg cm(-2)) at different incubation times (6, 12, 24, 48 or 72 h). Cell viability over 80% was observed for all nanoparticle treatment experiments, regardless of surface coatings, nanoparticle concentrations and incubation times. The much lower cell viability for cells treated with free ligands (e.g. ~10% for polyethylenimine) suggested that the surface coatings were tightly attached to the nanoparticle surfaces. The immune responses of cells to nanoparticles were evaluated by quantifying the expression of toll-like receptor 2 and tumor necrosis factor-α. The expression of tumor necrosis factor-α and toll-like receptor 2 were not significant in any case of the surface coatings, nanoparticle concentrations and incubation times. These results provide useful information to select nanoparticle surface coatings for biological and biomedical applications.
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama, USA.
authors.forename: Yaolin
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Sherwood
authors.affiliation: Department of Biological Science, The University of Alabama, Tuscaloosa, Alabama, USA.
authors.forename: Kimberly H
authors.initials: KH
authors.lastname: Lackey
authors.affiliation: Alabama Innovation and Mentoring of Entrepreneurs, The University of Alabama, Tuscaloosa, Alabama, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama, USA.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Bao
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005290:Ferric Compounds / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects; D009000:Monocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D011092:Polyethylene Glycols / Q000737:chemistry; D013499:Surface Properties; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D005290:Ferric Compounds; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha; C000499:ferric oxide; D011092:Polyethylene Glycols
keywords: cellular uptake and toxicity; immune response; iron oxide nanoparticles; monocytes; surface-dependent effects