Silicon-Doped Titanium Dioxide Nanotubes Promoted Bone Formation on Titanium Implants.

Area of Science:

• Biomaterials Science
• Surface Engineering
• Orthopaedic and Dental Implantology

Background:

• Titanium (Ti) implants are widely used but exhibit bioinertness, hindering osseointegration.
• Surface modification is crucial to enhance bone-Ti integration for improved implant performance.
• Existing titanium dioxide (TiO₂) nanotubes show promise but can be further optimized.

Purpose of the Study:

• To investigate the effect of silicon (Si) doping into TiO₂ nanotubes on Ti surfaces.
• To evaluate the osteogenic potential and in vivo bone integration of Si-doped TiO₂ nanotubes.
• To assess the suitability of Si-doped TiO₂ nanotubes as a bioactive surface modification for Ti implants.

Main Methods:

• Fabrication of Si-doped TiO₂ nanotubes on Ti substrates using plasma immersion ion implantation (PIII).
• In vitro assessment of osteogenic gene expression (Col-I, ALP, Runx2, OCN, OPN) and mineral deposition in MC3T3-E1 cells.
• In vivo pull-out mechanical testing of implants in rat femur after two weeks.

Main Results:

• Si-doped TiO₂ nanotubes significantly enhanced osteogenic gene expression and mineral matrix deposition compared to TiO₂ nanotubes and Ti alone.
• In vivo pull-out tests showed improved implant fixation strength: 18% over TiO₂-NT and 54% over Ti.
• Surface modification with Si-doped TiO₂ nanotubes promoted osteoblastic cell differentiation and bone-Ti integration.

Conclusions:

• Si-doped TiO₂ nanotubes effectively promote osteogenic differentiation and enhance bone-Ti integration.
• This surface modification strategy offers significant improvements in implant fixation strength.
• Si-doped TiO₂ nanotubes show considerable potential for developing next-generation bioactive Ti implants.