Evaluation of Functional SiO₂ Nanoparticles Toxicity by a 3D Culture Model

Context: as a kind of non-metal oxide SiO₂ NPs have been extensively used in biomedicine, pharmaceuticals and other industrial manufacturing fields, such as DNA delivery, cancer therapy… Our group had developed a method based on microemulsion process to prepare SiO₂ NPs incorporating photonic or magnetic nanocrystals and luminescent nanosized inorganic metal atom clusters. However, the toxicity of nanoparticles is known to be closely related to their physico-chemical characteristics and chemical composition. Object: it is therefore of interest to investigate the toxicity of these novel SiO₂ NPs to the cells that may come in contact. Materials and methods: the potential toxic effect of the functional @SiO₂ NPs containing Mo₆ clusters with or without gold nanoparticles was investigated, at concentrations 1 μg/mL, 10 μg/mL and 100 μg/mL each, on three different cell lines. Cell viability was measured by the MTT test in monolayer’s culture whereas the cytotoxicity in spheroid model was examined by the APH assay. In a second time, oxidative-stress-induced cytotoxicity was investigated through glutathione levels dosages. Results: the results indicated that both A549 and L929 cell lines did not exhibit susceptibility to functional @SiO₂ NPs-induced oxidative stress unlike KB cells. Discussion: SiO₂ NPs containing CMB may become toxic to cultured cells but only at a very high dosage level. Therefore, this toxicity depends on cell lines and more, on the model of cell cultures. The selection of appropriate cell line remains a critical component in nanotoxicology. Conclusion: these results are relevant to future applications of SiO₂ gold-cluster NPs in controlled release applications.