Differential expression of osteoblast-like cells on self-organized titanium dioxide nanotubes.

Background/purpose: Titanium dioxide nanotube (TNT) structures have been shown to enhance the early osseointegration of dental implants. Nevertheless, the optimal nanotube diameter for promoting osteogenesis remains unclear due to variations in cell types and manufacture of nanotubes. This study aimed to evaluate the differences in MC3T3-E1 and Saos-2 cells behavior on nanotubes of varying diameters.

Materials And Methods: TNT structures were fabricated by anodizing titanium foil at voltages ranging from 15V to 70V and annealed at 450 °C. Surface morphology and wettability were characterized using field emission scanning electron microscopy and water contact angle measurements, respectively. MC3T3-E1 and Saos-2 cells were cultured to evaluate biocompatibility. Early cell morphology and adhesion were visualized by scanning electron microscopy. Cell proliferation was quantified using CCK-8 assays, and differentiation was assessed through alkaline phosphatase assays. Osteogenesis-related gene expression was analyzed by real-time polymerase chain reaction (PCR), measuring runt-related transcription factor 2 (Runx-2), alkaline phosphatase (ALP), collagen type 1 (COL-1), osteocalcin (OCN), and Osteopontin (OPN) gene levels.

Results: Our results found that Saos-2 cells may be more suitable for TNT-related studies compared to MC3T3-E1 cells. Notably, the 65V nanotube group, with a diameter of 135.9 ± 15.83 nm, demonstrated the most significant osteogenic effect in our assays.

Conclusion: We propose that the use and screening of multiple cell lines prior to the evaluation of biomaterials can lead to more accurate in vitro experiments, thereby enhancing the reliability of biomaterial research.