Revisiting the impacts of silica nanoparticles on endothelial cell junctions and tumor metastasis

Inorganic nanoparticles have received great attention in the medical field. Noticeably, highly agglomerated commercial silica nanoparticles without any surface modification have been most recently reported to cause severe endothelial leakiness, which leads to extensive cancer cell intravasation and consequently promotes cancer metastasis. To clarify these biosafety issues, in this study we controllably synthesized mesoporous silica (m-SiO2) nanoparticles and then performed suitable surface decoration with polyethylene glycol (PEG). Such synthesized inorganic nanoparticles show a minimized destruction to the vascular system, leading to negligible effects on tumor metastasis in comparison with fumed silica. More importantly, the relative 24 h migration ratio of m-SiO2-PEG is as low as 0.17, suggesting that m-SiO2-PEG could effectively prevent cancer cells from migrating upon intracellular endocytosis. This study proves that the controllably synthesized and appropriately decorated m-SiO2 nanoparticles are highly biocompatible and can be used safely in nanomedicine, which is expected to encourage researchers to further push forward their investigations and clinical translations.