Tin dioxide nanofibers (SnDNFs) are small fibers with many applications in areas such as cosmetics, solar cells, toxic gas release sensors, and air pollution control. There have been few studies on the cytotoxicity of SnDNFs. The goal of this research was to evaluate the toxicity of electrospun SnDNFs in a lung cancer cell line (A549). Occupational exposure to SnDNFs, primarily through inhalation, has been linked to pulmonary disease, thus we used the A549 cell line, which has been used in both nanoparticle and pulmonary toxicity studies. Synthesized SnDNFs were characterized using scanning electron microscopy (SEM), Raman spectroscopy, and powder X-ray diffraction (PXRD). SEM images confirmed that the fibers were 200-300 nm in diameter, which is consistent with the fiber size used in industry. Raman spectroscopy and PXRD verified that the fibers were also in the rutile phase, a smaller and more stable crystalline structure. Following confirmation of the physical properties, A549 cells were treated with fiber concentrations ranging from 0.02-500 µg/mL. Cell proliferation was determined by comparing data from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, which measures Complex II activity in mitochondria, with general cell death, as measured by lactate dehydrogenase (LDH) release. Results from the MTT assay indicated an IC50 of 0.02 mg/mL, while the LDH assay showed that significant cell death did not occur until the fifth day of exposure (*p = 0.05). Gene transcription analysis using qRT-PCR of genes linked to oxidative stress, inflammation, and apoptosis was conducted, and showed inflammatory genes to be differentially expressed com-pared to controls. Taken together, these results suggest that toxicity due to rutile SnDNF exposure in A549 cells line likely occurs via inflammation, but requires least a five-day exposure to these nanofibers in vitro.
Available at: http://works.bepress.com/worlanyo_gato/49/