Cytotoxicity and intracellular dissolution of nickel nanowires

Abstract

The assessment of cytotoxicity of nanostructures is a fundamental step for their development as biomedical tools. As widely used nanostructures, nickel nanowires (Ni NWs) seem promising candidates for such applications. In this work, Ni NWs were synthesized and then characterized using vibrating sample magnetometry, energy dispersive X-Ray analysis and electron microscopy. After exposure to the NWs, cytotoxicity was evaluated in terms of cell viability, cell membrane damage and induced apoptosis/necrosis on the model human cell line HCT 116. The influence of NW to cell ratio (10:1 to 1000:1) and exposure times up to 72 hours was analyzed for Ni NWs of 5.4 µm in length, as well as for Ni ions. The results show that cytotoxicity markedly increases past 24 hours of incubation. Cellular uptake of NWs takes place through the phagocytosis pathway, with a fraction of the dose of NWs dissolved inside the cells. Cell death results from a combination of apoptosis and necrosis, where the latter is the outcome of the secondary necrosis pathway. The cytotoxicity of Ni ions and Ni NWs dissolution studies suggest a synergistic toxicity between NW aspect ratio and dissolved Ni, with the cytotoxic effects markedly increasing after 24 hours of incubation.Just Accepted by Nanotoxicology © 2015 Taylor & Francis. This provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon.DISCLAIMER: The ideas and opinions expressed in the journal's Just Accepted articles do not necessarily reflect those of Taylor & Francis (the Publisher), the Editors or the journal. The Publisher does not assume any responsibility for any injury and/or damage to persons or property arising from or related to any use of the material contained in these articles. The reader is advised to check the appropriate medical literature and the product information currently provided by the manufacturer of each drug to be administered to verify the dosages, the method and duration of administration, and contraindications. It is the responsibility of the treating physician or other health care professional, relying on his or her independent experience and knowledge of the patient, to determine drug dosages and the best treatment for the patient. Just Accepted articles have undergone full scientific review but none of the additional editorial preparation, such as copyediting, typesetting, and proofreading, as have articles published in the traditional manner. There may, therefore, be errors in Just Accepted articles that will be corrected in the final print and final online version of the article. Any use of the Just Accepted articles is subject to the express understanding that the papers have not yet gone through the full quality control process prior to publication. Cytotoxicity and intracellular dissolution of nickel nanowiresJose E. Perez 1, 2 , Maria F. Contreras 1 , Enrique Vilanova 2 , Laura P. Felix 1, 2 , Michael B.

Non-chemotoxic induction of cancer cell death using magnetic nanowires

“…The results showed that Ni NWs are quickly internalized (within less than 1 hour) by cultured colon cancer cells and do not cause extensive cytotoxicity at a concentration of 2.4 μg/mL and an incubation time of 1 hour, which confirms previous results obtained for incubation times up to 72 hours. 33 The highest and significant viability drop of 11% was found for a higher NW concentration (12 μg/mL) and 1 hour incubation.…”

“…The cytotoxic effects might increase with longer incubation times, as has been shown before. 33,36 This would have to be taken into account in in vivo applications. For instance, it has been shown that iron oxide nanoparticles remain in an organism for several days 56 or even up to 6 months.…”

“…30 The large number of studies that use Ni NWs in comparison to Fe might suggest that Ni is a better candidate material despite its reported genotoxicity and cytotoxicity in Ni-containing dust particles. 31 Even though no work has been done that directly compares the cytotoxicity of Fe and Ni NWs under the same experimental conditions (cell line, incubation times, concentrations), a cross-comparison among studies 32,33 reveals that Fe NWs are considerably less toxic at a given concentration than are Ni NWs. However, as mentioned above, the stronger aggregation of Fe NWs limits the use of pristine NWs, requiring passivation to overcome this limitation.…”

“…In addition to work on biological and biomedical applications, fundamental studies involving internalization into different cell lines, 34 the dependence of cytotoxicity on incubation time and NW concentration, 33,34 and length-dependent cytotoxicity 35 have been reported. Moreover, cellular processes such as increased levels of reactive oxygen species, 27 cell viability reduction, 27,36 and cell membrane leakage 36 have been shown to be activated solely by the incubation of cells with Ni NWs.…”

In vitro toxicity of Fe_mO_n, Fe_mO_n-SiO₂ composite, and SiO₂-Fe_mO_n core-shell magnetic nanoparticles

“…38 Phagocytic cells can actively engulf magnetic nanowires, as has been recently demonstrated in elegant experiments using selective chemical inhibitors of different internalization pathways. 39 …”