Investigation of toxicological effects of amorphous silica nanostructures with amine-functionalized surfaces on Vero cells.

Amorphous silica (SiO) nanostructures are described in the literature as having low toxicity and are widely used in many industrial products. However, surface modifications, such as amine-functionalization, can result in increased cytotoxicity. In this study, amorphous SiO nanostructures (SiO NS) were synthesized and amine-functionalized with two different amine molecules: primary (SiO NS@1) and tri-amine (SiO NS@3). The materials were characterized by transmission electron microscopy (TEM), zeta potential (ZP), effective diameter (ED) and surface area measurements, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The toxicity of the three SiO NS samples toward Vero cells was evaluated. According to the methyl thiazolyl tetrazolium (MTT) assay, the IC was 1.477 ± 0.12 g L for SiO NS, 0.254 ± 0.07 g L for SiO NS@1 and 0.117 ± 0.05 g L for SiO NS@3. The order of cytotoxicity was SiO NS@3 > SiO NS@1 » SiO NS. There was an increase in malondialdehyde (MDA) levels and ROS productions in the cells exposed to all three materials. Also, TEM images showed damage on the mitochondria and rough endoplasmic reticulum.