A: Cytotoxicity of SiO2 NPs in RAW 264.7 macrophages after incubation for 72 h with 20, 40, and 80 μg ML−1 of nanoparticles. LC20 values for the particles were 40, 10, 40, 20, and 20 μg mL−1 for Stöber 100, Meso 100, Meso 500, Disulfide Meso 100, and Disulfide Hollow 100 nanoparticles, respectively. B: Degradation percentages of the particles. The macrophages were treated with particles LC20 and incubated for 72 h. The cells were lysed, and Si content in the supernatant was measured using ICP-MS. As shown, Meso 100 particles have the highest degradation rate (3.8%) while Stöber 100 nanoparticles have the lowest (0.3%). Data are mean ± SD (N=6). **means statistically significant differences (Pvalue< 0.05) were observed for degradation percentages between Meso 100 and other nanoparticles. ANOVA followed by a Tukey’s post-hoc test was applied for statistical analyses.