Silica nanoparticles induce conformational changes of tau protein and oxidative stress and apoptosis in neuroblastoma cell line

Abstract The adverse effects of SiO 2 NPs on the biological systems like nervous system have not been well explored. This study aimed to evaluate the toxicity of SiO 2 NPs on the nervous system in vitro . Therefore, human tau protein and neuroblastoma cell line (SH-SY5Y) were used as targets. In this study we examined the side effects of SiO 2 NPs on tau protein structure using several techniques including CD, ANS fluorescence, UV–vis (360 nm), Congo red absorbance, TEM, and molecular dynamic. Also, the cytotoxicity effects of SiO 2 NPs against SH-SY5Y cell line were evaluated using MTT, ROS and apoptotic assays. Spectroscopic and molecular dynamic investigations indicated that natively unfolded structure of tau in the presence of SiO 2 NPs experienced a partially folded and amorphous aggregated structure. Cellular assay demonstrated that SiO 2 NPs exerted cytotoxic effect on SH-SY5Y cells through ROS accumulation and induction of apoptosis. Overall, these findings proved that SiO 2 NPs could induce adverse effects on tau structure and SH-SY5Y cell integrity. Moreover, further studies are required to elucidate the molecular mechanism of SiO 2 NPs-induced side effects in vivo .