No Evidence Of The Genotoxic Potential Of Gold, Silver, Zinc Oxide And Titanium Dioxide Nanoparticles In The SOS Chromotest Essay

Firstly, the synthesis of β-galactosidase constitutes the induction of SOS response by genetic toxins, and the level of alkaline phosphatase activity indicates a range of cytotoxicity. From the experiment, the β-galactosidase and phosphatase activities of E.Coli PQ37 exposed to nanoparticles Au NPs and other nanoparticles showed minimal changes. As such, Au NPs and the other nanoparticles used in the experiment were not genotoxic. However, it was noted that cytotoxicity for Au and Ag ions there was reduced alkaline phosphatase activity in parallel with β-galactosidase. This is an indicator that the ions are not genotoxic. There is need conduct tests where the nanoparticles are used in higher concentrations as this test was limited to the E.coli PQ37. Consequently, the tests for genotoxicity for effects such as DNA adduct, DNA lesion and DNA repair, need to use different test species such as mammalian species. Mammalian species are more relevant in assessing the genotoxicity of gold nanoparticles in human gene therapy.

Aneuploidogenic effects and DNA oxidation induced in vitro by differently sized gold nanoparticles

The study used gold nanoparticles (Au NPs) of between 5nm and 15nm. There is significant inhibition of cell proliferation and chromosomal damage in the human primary lymphocytes and murine macrophages (Raw264.7). Additionally, there is evidence of DNA strand breaks, pyrimidines and purines oxidative lesions. Exposure to high levels of Au NPs (15nm) resulted in high levels of damage to the Raw264.7. As such, the sizes of the Au NPs are critical in determining the genotoxic effects. Both levels of Au NPs caused a dose-dependent genotoxic effect. Further, there is evidence of aneuploidy and there is presence chromosome missegregation. Chromosome missegregation normally is used as an indicator of cancer cells. While the gold nanoparticles can be used for gene therapy, based on the findings of this study, they can as well trigger cancerous cells. Therefore, their application needs to be carefully used based on the levels used in gene therapy.

Mutagenic effects of gold nanoparticles induce aberrant phenotypes in

Drosophila melanogaster
Additionally, the Au NPs caused a number of developmental disorders as evidenced by the reduction in the number of adult individuals. An investigation in the Drosophila hemocytes indicated presence of DNA fragmentation. The hemocytes are critical in the sense that they are equivalent to the lymphocytes that are present in mammalian cells. The NPs may also reach the hemolymph causing severe damage to the circulating hemocytes. From molecular tests, the study indicated that levels of p53 protein were much higher for the treated organisms. P53 protein is activated because of exposure to genomic agents since they are supposed to maintain genomic integrity in multicellular organisms. Increase in levels of p53 serves to prevent the formation of tumors.
Based on the test of the mammalian cells and the Drosophila melanogaster, it is evident that gold nanoparticles significantly cause genotoxicity. Critical to gene therapy are issues of reproduction and physiological disorders that have been evident in the study of Drosophila melanogaster.