Biocompatibility analysis of NIH/3T3 cells exposed to silica-coated silver and silver nanoparticles

Despite the fact that silver nanoparticles (Ag NPs) have been used in widespread applications and that numerous studies have been performed to assess their cytotoxicity on various cell types, there is a lack of information regarding how to reduce the cytotoxicity of Ag NPs. Reduced or inhibited silver ions released from Ag NPs may promote their bioavailability in cells. In this study, we used silica-coated Ag NPs (Ag@SiO₂) in toxicity assays in vitro and compared the outcome with Ag NPs. In this study, NIH/3T3 cells were exposed for 30 min, 24 h, and 72 h to increasing concentrations of Ag NPs and Ag@SiO₂ NPs. The results showed that the viabilities of the cells were 51% and 41% after exposure to 10 μg/ml and 20 μg/ml of Ag NPs at 24 h post-exposure, respectively. For the same concentrations of Ag@SiO₂ particles, the viabilities were 91% and 74%, respectively. In addition, these NPs mostly located to the cytoplasm, not the nucleus, 72 h postexposure. Meanwhile, the cells treated with Ag NPs were less elongated than those treated with Ag@SiO₂ NPs. The data indicated that the silica coatings on the Ag NPs significantly decrease the cytotoxicity of the Ag NPs.