The toxicity of nanostructured materials and nanoparticles are very important considerations for many nanotechnology applications. Iron nanowires (NWs), as useful magnetic nanomaterials, may be good candidates for several biomedical applications. Here Fe NWs with an average diameter of about 50 nm were prepared by electrodeposition within the nanopores of anodic aluminum oxide (AAO) templates, and characterized by using scanning electron microcopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The cytotoxicity of the Fe NWs was studied at cell level. Specifically, the influence of concentration and size on the cytotoxicity of Fe NWs to HeLa cells was evaluated by MTT assay combined with direct morphology observations by TEM and phase contrast microscopy. The results clearly showed that the presence of Fe NWs had no significant effect on the cell proliferation and cell viability, even the HeLa cells exposed to Fe NWs at the high concentration of 10,000 per cell for 72 h still showed high cell viability of about 80%. From phase contrast microscopy, confocal laser scanning microscopy (CLSM) and TEM observations, it was found that Fe NWs were indeed internalized by HeLa cells. The cellular uptake process and results of Fe NWs demonstrated that as-prepared Fe NWs had not only a good biocompatibility but also a very low cytotoxicity.
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