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

The adverse effects of SiO NPs on the biological systems like nervous system have not been well explored. This study aimed to evaluate the toxicity of SiO 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 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 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 NPs experienced a partially folded and amorphous aggregated structure. Cellular assay demonstrated that SiO NPs exerted cytotoxic effect on SH-SY5Y cells through ROS accumulation and induction of apoptosis. Overall, these findings proved that SiO 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 NPs-induced side effects in vivo.