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.