Effects of silica–gentamicin nanohybrids on osteogenic differentiation of human osteoblast-like SaOS-2 cells

INTRODUCTION: In recent years, there has been an increasing interest in silica (SiO(2)) nanoparticles (NPs) as drug delivery systems. This interest is mainly attributed to the ease of their surface functionalization for drug loading. In orthopedic applications, gentamicin-loaded SiO(2) NPs (nanohybrids) are frequently utilized for their prolonged antibacterial effects. Therefore, the possible adverse effects of SiO(2)–gentamicin nanohybrids on osteogenesis of bone-related cells should be thoroughly investigated to ensure safe applications. MATERIALS AND METHODS: The effects of SiO(2)–gentamicin nanohybrids on the cell viability and osteogenic differentiation of human osteoblast-like SaOS-2 cells were investigated, together with native SiO(2) NPs and free gentamicin. RESULTS: The results of Cell Count Kit-8 (CCK-8) assay show that both SiO(2)–gentamicin nanohybrids and native SiO(2) NPs reduce cell viability of SaOS-2 cells in a dose-dependent manner. Regarding osteogenesis, SiO(2)–gentamicin nanohybrids and native SiO(2) NPs at the concentration range of 31.25–125 μg/mL do not influence the osteogenic differentiation capacity of SaOS-2 cells. At a high concentration (250 μg/mL), both materials induce a lower expression of alkaline phosphatase (ALP) but an enhanced mineralization. Free gentamicin at concentrations of 6.26 and 9.65 μg/mL does not significantly influence the cell viability and osteogenic differentiation capacity of SaOS-2 cells. CONCLUSIONS: The results of this study suggest that both SiO(2)–gentamicin nanohybrids and SiO(2) NPs show cytotoxic effects to SaOS-2 cells. Further investigation on the effects of SiO(2)–gentamicin nanohybrids on the behaviors of stem cells or other regular osteoblasts should be conducted to make a full evaluation of the safety of SiO(2)–gentamicin nanohybrids in orthopedic applications.