Osseointegration and anti-infection of dental implant under osteoporotic conditions promoted by gallium oxide nano-layer coated titanium dioxide nanotube arrays

The insufficient osteointegration between titanium (Ti) based dental implants and surrounding bone tissue under osteoporotic conditions, as well as implant-associated infections usually associate with dental implant failure. Gallium (Ga) has drawn increasing attention due to its antibacterial ability and pro-osteogenic property. Herein, we established a facile strategy to deposit gallium oxide (Ga2O3) nano-layer on titanium dioxide nanotube (TNT) arrays by magnetron sputtering. Both Ga2O3@TNT/50 W and Ga2O3@TNT/100 W specimens were prepared at different powers (50 W and 100 W), respectively, which all achieved a sustained release of Ga3+ ion for over 14 days. In vitro results showed that Ga2O3@TNT/50 W sample has good biocompatibility and osteogenic activity, compared with TNT and Ga2O3@TNT/100 W samples. Moreover, both Ga2O3@TNT/50 W and Ga2O3@TNT/100 W samples possess potent antibacterial properties, due to the released Ga3+ ion. Furthermore, in vivo results indicated that the Ga2O3@TNT/50 W showed excellent in vivo antibacterial ability and promoted new bone formation effectively compared with TNT implants in an osteoporotic rat model with Staphylococcus aureus (S. aureus) infection. Therefore, such Ga2O3 deposition coating strategy provides a valuable guidance for the potential future development of Ga-doped dental implants and TNT based drug loading surfaces for clinical applications.