Journal of School of Public Health and

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Background and aim: In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration (NOAEC), inhibitory concentration 50 (IC50), and Total Lethal Concentration (TLC).

Materials and Methods: Human epithelial lung cells were exposed to different concentrations (1 to 1500 µg/ml) of carbon nanotubes and chrysotile for 6 and 24 hours. Cytotoxicity was assessed using the MTT assay. NOAEC, IC50, and TLC idices were determined by probit analysis.

Results: The results showed statistically significant correlations (p<0.001) between cytoxicity and exposure concentration in the case of all the three compounds. The NOAEC and IC50 indices were lowest for the multi-walled carbon nanotubes, while the single-walled carbon nanotubes showed the lowest TLC index.

Conclusion: Cytotoxicity of multi-walled carbon nanotubes at low concentrations was higher than that of single-walled carbon nanotubes and chrysotile. This would mean that exposure to this compound occurs at low concentrations. Thus, cytotoxicity of multi-walled carbon nanotubes is a cause for concern. It can be concluded, then, that, like chrysotile fibers, crabon nanotubes are also considerably toxic to human epithelial lung cells.

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Background and Aim: The aggregation of misfolded proteins leads to various cellular malfunctions and disorders such as Alzheimer’s disease. The conventional treatments of such diseases often fail due to their inability to cross the blood-brain barrier. The ability of nanoparticles to influence protein folding and aggregation and, as a result, their potential therapeutic effect in diseases involving protein aggregation, sounds promising. The objective of this study was to determine the effect of silver nanoparticles (AgNPs) on the amyloid aggregation of Hen Egg White Lysozyme (HEWL).
Material and Methods: Lysozyme was dissolved at 2 mg/mL in a 50 mM glycine buffer (pH 2.5) and incubated at 57 °C while being stirred gently with Teflon magnetic bar; the result was conversion of lysozyme to amyloid. The effect of the particles was assessed using different technics: Thioflavin T (ThT), Congo Red, atomic force microscopy (AFM) and Toxic test (MTT). Data were analyzed using SPSS 16, the statistical test being the independent t-test.
Results: Incubation of lysozyme with AgNPs at a concentration of 3-60 mcg/L could inhibit the HEWL fibrillation (p<0.05). Surprisingly, the lowest concentration (3 mcg/L) was found to be the most effective; at this concentration, the lag time (nucleation phase) became longer and the fibrillation phase considerably shortened. In addition, the cytotoxicity of the aggregated amyloids in the cell culture decreased.
Conclusion: Based on the findings, it is concluded that silver nanoparticle surfaces can actas nano-chaperones and inhibit HEWL fibrillation; thus, they can potentially be used in the treatment of Alzheimer’s disease.