Dose-dependent cell necrosis induced by silica nanoparticles.

In recent years, much attention has been given to nanoparticles (NPs) due to their many possible applications, and as research has progressed, these NPs have become valuable tools for medical purposes. Among many different types of NPs, silica nanoparticles (SiO₂NPs) have been specifically evaluated for medical purposes and have also been used in many different types of products. Although SiO₂NPs have already been applied and are believed to be nontoxic, there is still a concern regarding possible adverse effects that may be triggered after SiO₂NP exposure. Therefore, in the present study, we employed a recommended cell line (BALB/c 3 T3) for the toxicity evaluation to investigate the cytotoxic effects of SiO₂NPs produced by chemical synthesis at a laboratory scale. First, we employed OECD guideline 129 in order to evaluate cytotoxicity effects and also estimate the starting doses for acute oral systemic toxicity tests. We evaluated the cytotoxic effects of two types of SiO₂NPs (nonfluorescent and fluorescent) and found that they were not significantly different (IC₅₀ = 1986.39 ± 237 μg/ml and IC₅₀ = 1861.13 ± 186.72 μg/ml, respectively). Then, we used the predicted LD₅₀ of both types of SiO₂NPs to suggest that they could be categorized as GHS category 4 substances. By ultrastructural evaluation, we found that SiO₂NPs are internalized by 3 T3 cells and are located in vacuole-like structures with no other significant changes in cell structure. We also found that SiO₂NPs lead to cell necrosis in a dose-dependent manner.