Antibacterial Effect of Silver Nanoparticles Coated Titanium Nanosheet

Objectives: Postoperative infection around titanium implants remains a problem that eventually leads to implant failure. Our previous study showed that high-concentration alkali-treated titanium had a hydrophilic surface with a nanonetwork structure and greatly enhanced osteogenic activity. We named this excellent surface titanium nanosheet. Here, we aimed to produce silver nanoparticles in situ on the surface of titanium nanosheets via AgNO₃ solution immersion and UV irradiation, and evaluate the antibacterial effect of the surface.
Methods: Titanium discs were immersed in 10M NaOH solution at 30°C for 24h. Afterwards, the discs were immersed in 0.1M AgNO₃ solution at 40°C for 3h and irradiated with UV for 15min. SEM, XPS and XRD was utilized to confirm the in situ production of silver nanoparticles. Actinomyces oris, an acknowledged initial colonizer in subgingival plaque of the oral ecosystem, is applied to confirm the antibacterial effect. All samples were incubated with bacterial liquid aerobically for 1h for the initial adhesion and 24h for the biofilm formation. Live/Dead staining and Crystal Violet assay were used study bacterial initial adhesion and biofilm formation respectively.
Results: Titanium nanonetwork structure was slightly changed after AgNO₃ solution immersion. Silver nanoparticles attached to the nanonetwork surface with a diameter of 20-50nm. Live/Dead staining assay showed that abundant red staining dead bacteria was observed by CLSM. Crystal violet assay demonstrated that biofilm formation was significantly inhibited (P<0.05).
Conclusions:
Silver nanoparticles coated titanium nanosheet had a strong antibacterial effect and might be a new choice for dental implant materials that could potentially be used when bacteria contamination became a risk for implanting application.