Efeito da decorionação na avaliação da toxicidade de nanopartículas de dióxido de titânio em embriões de Danio rerio

Abstract

Nanoparticles, such as titanium dioxide nanoparticles, have gained significant importance in industrial production and scientific advancements. Their unique and enhanced physicochemical properties spark interest both in applying them in many fields and in investigating the risks they pose to human health and the environment. In this context, ecotoxicity models help to fill knowledge gaps in the field of nanotoxicology. The fish species Danio rerio stands out due to its genetic similarity to humans and advantages as a model organism, such as its embryo assays being considered in vitro. However, the structure that protects the embryo from external agents - the chorion - often interferes with toxicological assessments. Therefore, this study aims to investigate the influence of the chorion on the toxicity analysis of titanium dioxide nanoparticles. For this purpose, a toxicity study was conducted with Danio rerio embryos, using a conventional test and a test with dechorionation, and toxicity parameters were analyzed. Confocal fluorescence microscopy was also used to assess cellular damage. The conventional acute toxicity test and the test with dechorionation both suggested that titanium dioxide nanoparticles are not toxic. Variations in larval length and the adsorption of aggregated particles on the chorion surface demonstrated that it influences toxicity results. Confocal microscopy revealed the cytotoxicity of titanium dioxide nanoparticles, which caused cellular damage to embryos and larvae. The chorion also appeared to affect the interaction between the embryo and the nanoparticles. Thus, dechorionation of the embryos ensured more reliable results and highlighted the importance of considering the presence of the chorion as a potential interference in nanoparticle toxicity studies using fish embryos. It is expected that this and other improvements will continue to be made in ecotoxicological and nanotoxicological assays, in order to establish clear consensus regarding the safety of these nanoparticles.