Nickel Release, ROS Generation and Toxicity of Ni and NiO Micro- and Nanoparticles

• Published in: PloS one Vol. 11; no. 7; p. e0159684
• Main Authors: Latvala, Siiri, Hedberg, Jonas, Di Bucchianico, Sebastiano, Möller, Lennart, Odnevall Wallinder, Inger, Elihn, Karine, Karlsson, Hanna L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.07.2016; Public Library of Science (PLoS)
• Subjects: A549 Cells; Analytical chemistry; Applied Environmental Science; Biological Assay; Biology and life sciences; Biomimetic Materials - chemistry; Cancer; Cell Survival - drug effects; Cytotoxicity; Damage detection; Deoxyribonucleic acid; Dissolution; DNA; DNA Damage; DNA repair; Engineering and Technology; Environmental health; Environmental science; Genotoxicity; Health aspects; Health risks; Horseradish Peroxidase - chemistry; Humans; Lung cancer; Lung diseases; Lysosomes - chemistry; Medicin och hälsovetenskap; Medicine and Health Sciences; Metal Nanoparticles - toxicity; Metal Nanoparticles - ultrastructure; Metal oxides; Metals; Microscopy, Electron, Transmission; Nanoparticles; Nickel; Nickel (Metal); Nickel - toxicity; Nickel oxides; Occupational exposure; Occupational health; Oxazines - chemistry; Oxidative stress; Oxygen; Particle Size; Particulates; Physical Sciences; Properties; Reactive oxygen species; Reactive Oxygen Species - metabolism; Research and Analysis Methods; Respiratory tract; Respiratory tract diseases; Risk assessment; Risk factors; Stainless steel; Studies; tillämpad miljövetenskap; Toxicity; Toxicology; Xanthenes - chemistry; United States
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0159684

Occupational exposure to airborne nickel is associated with an elevated risk for respiratory tract diseases including lung cancer. Therefore, the increased production of Ni-containing nanoparticles necessitates a thorough assessment of their physical, chemical, as well as toxicological properties. The aim of this study was to investigate and compare the characteristics of nickel metal (Ni) and nickel oxide (NiO) particles with a focus on Ni release, reactive oxygen species (ROS) generation, cellular uptake, cytotoxicity and genotoxicity. Four Ni-containing particles of both nano-size (Ni-n and NiO-n) and micron-size (Ni-m1 and Ni-m2) were tested. The released amount of Ni in solution was notably higher in artificial lysosomal fluid (e.g. 80-100 wt% for metallic Ni) than in cell medium after 24h (ca. 1-3 wt% for all particles). Each of the particles was taken up by the cells within 4 h and they remained in the cells to a high extent after 24 h post-incubation. Thus, the high dissolution in ALF appeared not to reflect the particle dissolution in the cells. Ni-m1 showed the most pronounced effect on cell viability after 48 h (alamar blue assay) whereas all particles showed increased cytotoxicity in the highest doses (20-40 μg cm2) when assessed by colony forming efficiency (CFE). Interestingly an increased CFE, suggesting higher proliferation, was observed for all particles in low doses (0.1 or 1 μg cm-2). Ni-m1 and NiO-n were the most potent in causing acellular ROS and DNA damage. However, no intracellular ROS was detected for any of the particles. Taken together, micron-sized Ni (Ni-m1) was more reactive and toxic compared to the nano-sized Ni. Furthermore, this study underlines that the low dose effect in terms of increased proliferation observed for all particles should be further investigated in future studies.