Assessing risks caused by nickel-containing nanomaterials: hazard characterization in vivo

Nanoparticles (NP) of nickel (Ni) and its compounds are promising materials for being used as catalysts in chemical, pharmaceutical and food industry; as construction materials in electronics and optoelectronics, in manufacturing current sources, medications, diagnostic preparations, and pesticides. Annual production volumes for these materials in their nanoform are equal to dozen tons and are expected to growth further. According to data obtained via multiple research nanoforms of Ni and its compounds are toxic to many types of cells; stimulate apoptosis; and can induce malignant transformation in vitro. It indicates that this group of nanomaterials can possibly be hazardous for human health. Risk assessment includes such a necessary stage as quantitative hazard characterization, that is, establishing toxic and maximum no-observed-adverse-effect levels (NOAEL) for a nanomaterial that penetrates into a body via inhalation, through undamaged skin, or the gastrointestinal tract. Experiments in vivo performed on laboratory animals with Ni-containing materials revealed overall toxic effects; toxicity to specific organs (including hepatoxoticity and cardiotoxicity); atherogenic, allergenic, and immune-toxic effects, as well as reproductive toxicity. There are multiple available data indicating that all Ni-containing nanomaterials are genotoxic and mutagenic, though data on their carcinogenic potential are rather scarce. Factors that determine toxicity of Ni and its compounds in nanoform are their ability to penetrate through biological barriers and to release free Ni++ ions in biological media. The review focuses on analyzing and generalizing data on toxicity signs in vivo and effective toxic doses under various introductions of Ni and its compounds in nanoform into a body over a period starting predominantly from 2011.