Avaliação do potencial citogenotóxico de nanopartículas de dióxido de titânio em Lactuca sativa L. (ASTERACEAE)

Abstract

Titanium dioxide (TiO2) is a metallic oxide, found in nature, biologically inert in humans and animals and widely used due to its photocatalytic capacity and its ability to offer whiteness and opacity. With the advent of nanotechnology, in recent years, the use of TiO2 in the form of nanoparticle (NP) has grown considerably. This nanomaterial has been used as an additive in paints, in the production of paper, rubber, medicines, food products and cosmetics. As a result of the increased use and growth in the production of titanium dioxide nanoparticles (TiO2NPs), there is greater release of these nanoparticles into the environment and, as a result, concerns are intensified in relation to the toxic potential of these nanomaterials in ecosystems, resulting in want to know its behavior and its risks. Thus, the aim of the present work was to evaluate the cytogenotoxic potential of titanium dioxide nanoparticles in the plant model Lactuca sativa L. (Asteraceae). For this, TiO2NPs (JRCNM01001a, European Union) were characterized by Dynamic Light Scattering (DLS) and by Zeta Potential to identify the hydrodynamic size, polydispersion index and surface charge. Then, tests were carried out to analyze phytotoxicity, cytotoxicity and genotoxicity. For the experiments, seeds of Lactuca sativa L. were germinated in petri dishes containing TiO2NPs in the number of 10; 100 and 1000 µg / mL, for 72h, at 25ºC and in the dark. Phytotoxicity, cytotoxicity and genotoxicity data were statistically presented by ANOVA and as means compared by Tukey test, p values <0.05 were considered. The data obtained by DLS indicated an average hydrodynamic size of 505.33 nm. Even though TiO2 nanoparticles aggregate and form agglomerates with a larger size, as found, primary particle sizes still remain a significant feature and can cause toxicity. The average PDI of 0.353 found indicates a sample with average polydispersion, since the force applied by the sonicator cannot be sufficient to break rigid bonds between aggregates, surpassing only the van der Waals frames of the agglomerates. Zeta potential of -27.57 mV, being close to a stable condition of ± 30 mV. An analysis of the germination rate and along the root surface indicated that TiO2NPs were not phytotoxic to L. sativa meristematic cells, under the experimental conditions and conditions tested. However, a cytogenetic analysis revealed that the rules of 10; 100 and 1000 µg / mL of TiO2NPs show cytogenotoxicity.