ABSTRACT
Although several studies assess the biological effects of micro and titanium dioxide nanoparticles (TiO2 NPs), the literature shows controversial results regarding their effect on bone cell behavior. Studies on the effects of nanoparticles on mammalian cells on two-dimensional (2D) cell cultures display several disadvantages, such as changes in cell morphology, function, and metabolism and fewer cell-cell contacts. This highlights the need to explore the effects of TiO2 NPs in more complex 3D environments, to better mimic the bone microenvironment. This study aims to compare the differentiation and mineralized matrix production of human osteoblasts SAOS-2 in a monolayer or 3D models after exposure to different concentrations of TiO2 NPs. Nanoparticles were characterized, and their internalization and effects on the SAOS-2 monolayer and 3D spheroid cells were evaluated with morphological analysis. The mineralization of human osteoblasts upon exposure to TiO2 NPs was evaluated by alizarin red staining, demonstrating a dose-dependent increase in mineralized matrix in human primary osteoblasts and SAOS-2 both in the monolayer and 3D models. Furthermore, our results reveal that, after high exposure to TiO2 NPs, the dose-dependent increase in the bone mineralized matrix in the 3D cells model is higher than in the 2D culture, showing a promising model to test the effect on bone osteointegration.
ABSTRACT
INTRODUCTION: This article reports, for the first time, the occurrence of Panstrongylus megistus in the Brazilian Western Amazon. METHODS: Specimens of P. megistus were collected in the cities of Rio Branco, Acre and Extrema, Rondônia. RESULTS: The number of triatomine species in the State of Acre increased from eight to nine and in Rondônia from seven to eight. This was also the first report of P. megistus in the Brazilian Western Amazon. CONCLUSION: The occurrence of P. megistus in the Western Amazon evidences an epidemiological alert, since it is an important vector of T. cruzi.
