Showing 3 results for Toxicity
M.r Zare, K Naddafi,
Volume 8, Issue 4 (2-2011)
Abstract
Background and Aim: Specific and unique characteristics of nanoparticles may entail specific and unique hazards. In addition, they may also exhibit toxicity under certain conditions. This study was conducted to investigate the toxicity of phenol-exposed and phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles.
Materials and Methods: Stock solutions of the afore-mentioned nanoparticles were prepared at different concentrations and a sample of each was exposed to phenol. This was followed by exposing Daphnia Magna to the phenol- and non-phenol-exposed nanoparticles. LC50, NOEC and the concentrations at which mortality rates were 100% were determined 12 to 96 hours after exposure, while for the determination of the mortality rate of Daphnia the Probit model in SPSS version16 software was used.
Results: The results revealed that (1). The 48-hr LC50 values for phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles were 2705 and over 15000 mg/m3, respectively. The corresponding values for the phenol-exposed samples were 414 and 1253. (2). The 48-hr NOEC values for the phenol-exposed TiO2 and FeTiO2 were 41 and 789, respectively, the corresponding values for unexposed samples being 1253 and over 15000 mg/m3. (3). In addition, the 48-hr 100% mortality rates for phenol-unexposed nano-TiO2 and nano-Fe/TiO2 particles were, respectively, 1253 and over 15000 mg/m3, while for the phenol-exposed samples the corresponding rates were 1090 and over 2108.
Conclusion: With regard to 48-hr LC50, the findings show that the toxicity of both nano-Fe: TiO2 and TiO2 increases as a result of exposure to phenol, the increase being 12-fold for the former and 6.5-fold for the latter. In general, however, based on LC50, it can be said that the toxicity of Fe:TiO2 nanoparticles, which has better catalytic characteristics, is lower in comparison to TiO2 nanoparticles. Thus, using Fe:TiO2 in preference to pure TiO2 should be investigated further, as it will be less hazardous to the environment.
Yousef Mohammadian, Seyed Jamaledin Shahtaheri, Ali Akbar Sabour Yaraghi, Hossein Kakooei, Mohammad Hajaghazadeh,
Volume 10, Issue 4 (3-2013)
Abstract
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.
Hassan Ramshini, Azam Sadat Moghaddasi,
Volume 16, Issue 2 (9-2018)
Abstract
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.
