The nanotechnology industry is growing rapidly, encompassing a wide range of industries from medicine to engineering. Due to their small size, as well as physical and chemical properties, the application of nanoparticles is very versatile e.g. nanoparticles can be used to improve the properties of heat resistance and elasticity of a given material. The increasing use of nanoparticles calls for deeper studies of their genotoxicity. Zinc oxide (ZnO) nanoparticles (NP) were selected for this study because they are a key ingredient in many products such as sunscreens, paints, asphalt, electric diodes and chemical catalysts.
It has been observed in previous research that ZnO nanoparticles can cause oxidative stress when they enter the cell1. ZnO NPs cause formation of intercellular reactive oxygen species that are responsible for changes in mitochondrial potential along with swollen mitochondria. Moreover, ZnO NP can adhere to chromosomes involved in the normal process of mitosis, and thus can cause abnormalities that stop normal cell division and the cell cycle. For these reasons, it is important to find out what is the lowest level of concentration can cause detrimental health effects.
To assess the potential toxicity of zinc oxide Allium cepa assay was performed. The prepared onions were transferred to selected concentrations of 6 ZnO NP solutions varying from 0.2 to 625 ppm. The effective concentration EC50 was determined from the growth curves by performing a root inhibition test and evaluating these concentrations. The EC50 was obtained at 0.9 ppm with the 'Shakespeare' cultivar, which indicates the detrimental potency of the substance. In this part of the experiment, a. regression analysis was performed. Root length after 96 hours was regressed on levels of ZnO concentration in the solution. This dependence was assessed as statistically significant, noting that p-value < 0.01.