Toxicity Assessment of SiO(2) and TiO(2) in Normal Colon Cells, In Vivo and in Human Colon Organoids

We conducted systemic assessments on the toxicity of silicon dioxide (SiO(2)) and titanium dioxide (TiO(2)) nanoparticles using different forms of normal colon cells (CCD-18Co), in vivo and in human colon organoids. The in vivo acute oral toxicity data showed that the LD(50) values are greater than 2000 mg/kg for both the SiO(2) and TiO(2) nanoparticles; however, the SiO(2) and TiO(2) nanoparticles induced cytotoxicity in two-dimensional CCD-18Co cells and three-dimensional CCD-18Co spheroids and human colon organoids, with IC(50) values of 0.6, 0.8 and 0.3 mM for SiO(2) and 2.5, 1.1 and 12.5 mM for TiO(2) nanoparticles, respectively. The data suggest that, when SiO(2) and TiO(2) are in nanoparticle form, cytotoxicity is induced; thus, care should be taken with these materials.