title: Toxicity of silver ions and differently coated silver nanoparticles in Allium cepa roots.
abstract: Silver nanoparticles (AgNPs) are the dominating nanomaterial in consumer products due to their well-known antibacterial and antifungal properties. To enhance their properties, different surface coatings may be used, which affect physico-chemical properties of AgNPs. Due to their wide application, there has been concern about possible environmental and health consequences. Since plants play a significant role in accumulation and biodistribution of many environmentally released substances, they are also very likely to be influenced by AgNPs. In this study we investigated the toxicity of AgNO3and three types of laboratory-synthesized AgNPs with different surface coatings [citrate, polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB)] on Allium cepa roots. Ionic form of Ag was confirmed to be more toxic than any of the AgNPs applied. All tested AgNPs caused oxidative stress and exhibited toxicity only when applied in higher concentrations. The highest toxicity was recorded for AgNPs-CTAB, which resulted with increased Ag uptake in the roots, consequently leading to strong reduction of the root growth and oxidative damage. The weakest impact was found for AgNPs-citrate, much bigger, negatively charged NPs, which also aggregated to larger particles. Therefore, we can conclude that the toxicity of AgNPs is directly correlated with their size, overall surface charge and/or surface coating.
authors.affiliation: Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
authors.forename: Petra
authors.initials: P
authors.lastname: Cvjetko
authors.affiliation: Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
authors.forename: Anita
authors.initials: A
authors.lastname: Milošić
authors.affiliation: Department of Pharmaceutical Botany, Faculty of Pharmacy and Biochemistry, University of Zagreb, Ul. Ante Kovačića 1, 10000 Zagreb, Croatia.
authors.forename: Ana-Marija
authors.initials: AM
authors.lastname: Domijan
authors.affiliation: Institute for Medical Research and Occupational Health, Ksaverska cesta 2, 10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Vinković Vrček
authors.affiliation: Department of Ecology, Institute of Public Health ''Dr. Andrija Štampar'', Mirogojska cesta 16, 10000 Zagreb, Croatia.
authors.forename: Sonja
authors.initials: S
authors.lastname: Tolić
authors.affiliation: Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
authors.forename: Petra
authors.initials: P
authors.lastname: Peharec Štefanić
authors.affiliation: Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Graz Centre for Electron Microscopy (ZFE), Austrian Cooperative Research (ACR), Steyrergasse 17, 8010 Graz, Austria.
authors.forename: Ilse
authors.initials: I
authors.lastname: Letofsky-Papst
authors.affiliation: Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
authors.forename: Mirta
authors.initials: M
authors.lastname: Tkalec
authors.affiliation: Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia. Electronic address: bbalen@biol.pmf.hr.
authors.forename: Biljana
authors.initials: B
authors.lastname: Balen
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000633:toxicity*; D000975:Antioxidants / Q000378:metabolism; D019343:Citric Acid / Q000737:chemistry; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D007477:Ions / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D053768:Metal Nanoparticles / Q000633:toxicity*; D019697:Onions / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011205:Povidone / Q000737:chemistry; D012834:Silver / Q000378:metabolism / Q000633:toxicity*; D012835:Silver Nitrate / Q000633:toxicity
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D007477:Ions; D010940:Plant Proteins; D019343:Citric Acid; D012834:Silver; D012835:Silver Nitrate; D011205:Povidone
keywords: Allium cepa; Antioxidant enzymes; Oxidative stress; Silver nanoparticles; Silver nitrate