Evaluation of Toxicological Effects of ZnO and CuO Nanoparticles with Taraxacum officinale as Bioindicator

Abstract

Nanoparticles are rising worries because of recent reports about potential toxicity amid the incorporation of these emerging materials into consumer products, and industrial and scientific applications. New developments in the automotive industry are incorporating novel materials, which have increased the emission of nanoparticles into the atmosphere. To overcome the difficulty of detecting and characterizing atmospheric nanoparticles, alternative methods have been proposed, just as the indirect detection and characterization with bioindicators. We report the use of Taraxacum officinale as a sentinel organism to describe the effects of atmospheric nanostructured pollutants. ZnO and CuO nanoparticles (ZnO-NPs, CuO-NPs) were selected for this study, as they are two of the most present nanomaterials in the emerging automotive industry. The physiological effect on Taraxacum officinale exposure to ZnO-NPs and CuO-NPs was evaluated through growth rate, and total chlorophyll content; and comet assay was performed to evaluate the DNA damage. The exposure of plants was made by nebulizing dispersions of the nanoparticles. The exposure to ZnO-NPs presented the maximum DNA damage at a concentration of 100 mg/L. The DNA damage by both studied nanoparticles showed a significant difference against its bulk counterparts. Scanning electron microscopy (SEM) micrographs showed an accumulation of nanoparticles near the stomata. The study demonstrated the feasibility of T. officinale as a bioindicator of air-related nanoparticles toxicity, and the high sensitivity of the comet assay for this approach.