Exposure to boron trioxide nanoparticles and ions cause oxidative stress, DNA damage, and phenotypic alterations in Drosophila melanogaster as an in vivo model

Boron trioxide nanoparticles (B2O3 NPs) have recently been widely used in a range of applications including electronic device technologies, acousto-optic apparatus fields, and as nanopowder for the production of special glasses. We propose Drosophila melanogaster as a useful in vivo model system to study the genotoxic risks associated with NP exposure. In this study, we have conducted a genotoxic evaluation of B2O3 NPs (size average 55.52 +/- 1.41 nm) and its ionic form in D. melanogaster. B2O3 NPs were supplied to third instar larvae at concentrations ranging from 0.1-10 mM. Toxicity, intracellular oxidative stress (reactive oxygen species, ROS), phenotypic alterations, genotoxic effect (via the wing somatic mutation and recombination test, SMART), and DNA damage (via Comet assay) were the end-points evaluated. B2O3 NPs did not cause any mutagenic/recombinogenic effects in all tested non-toxic concentrations in Drosophila SMART. Negative data were also obtained with the ionic form. Exposure to B2O3 NPs and its ionic form (at two highest concentrations, 2.5 and 5 mM) was found to induce DNA damage in Comet assay. Additionally, ROS induction in hemocytes and phenotypic alterations were determined in the mouths and legs of Drosophila. This study is the first study reporting genotoxicity data in the somatic cells of Drosophila larvae, emphasizing the importance of D. melanogaster as a model organism in investigating the different biological effects in a concentration-dependent manner caused by B2O3 NPs and its ionic form. The obtained in vivo results contribute to improvement the genotoxicity database on the B2O3 NPs.