Dual effects and mechanism of TiO2 nanotube arrays in reducing bacterial colonization and enhancing C3H10T1/2 cell adhesion

Primary human nasal epithelial cell response to titanium surface with a nanonetwork structure in nasal implant applications

In nasal reconstruction applications, the response of cells to titanium (Ti) implants is largely determined by the surface characteristics of the implant. This study investigated an electrochemical anodization surface treatment intended to improve the response of primary human nasal epithelial cells (HNEpC) to Ti surfaces in nasal implant applications. We used a simple and fast electrochemical anodization treatment, i.e., applying anodic current, to produce a titanium dioxide (TiO2) nanonetwork layer on the Ti surface with average lateral pore size below 100 nm, depending on the current applied. The TiO2 nanonetwork layer exhibited enhanced hydrophilicity and protein adsorption ability compared with untreated Ti surfaces. In addition, the spreading morphology, cytoskeletal arrangement, and proliferation of HNEpC on the nanonetwork layer indicated excellent cell response characteristics. This research advances our understanding regarding the means by which a TiO2 nanonetwork layer can improve the response of HNEpC to Ti surfaces in nasal implant applications.

Inhibited bacterial biofilm formation and improved osteogenic activity on gentamicin-loaded titania nanotubes with various diameters

Titania nanotubes loaded with antibiotics can deliver a high concentration of antibiotics locally at a specific site, thereby providing a promising strategy to prevent implant-associated infections. In this study we have fabricated titania nanotubes with various diameters (80, 120, 160, and 200 nm) and 200 nm length via electrochemical anodization. These nanotubes were loaded with 2 mg of gentamicin using a lyophilization method and vacuum drying. A standard strain, Staphylococcus epidermidis (American Type Culture Collection 35984), and two clinical isolates, S. aureus 376 and S. epidermidis 389, were selected to investigate the anti-infective ability of the gentamicin-loaded nanotubes (NT-G). Flat titanium (FlatTi) and nanotubes with no drug loading (NT) were also investigated and compared. We found that NT-G could significantly inhibit bacterial adhesion and biofilm formation compared to FlatTi or NT, and the NT-G with 160 nm and 200 nm diameters had stronger antibacterial activity because of the extended drug release time of NT-G with larger diameters. The NT also exhibited greater antibacterial ability than the FlatTi, while nanotubes with 80 nm or 120 nm diameters had better effects. Furthermore, human marrow derived mesenchymal stem cells were used to evaluate the effect of nanotubular topographies on the osteogenic differentiation of mesenchymal stem cells. Our results showed that NT-G and NT, especially those with 80 nm diameters, significantly promoted cell attachment, proliferation, spreading, and osteogenic differentiation when compared to FlatTi, and there was no significant difference between NT-G and NT with the same diameter. Therefore, nanotube modification and gentamicin loading can significantly improve the antibacterial ability and osteogenic activity of orthopedic implants.