Injectable Nanofiber Gel Enhances Osseointegration in a Rabbit Model

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• High insertion torque can lead to delamination of conventional bioactive implant coatings, causing debris and hindering osseointegration.
• Existing implant surfaces face challenges in achieving optimal biomechanical stability and bone formation.
• There is a need for advanced interface materials to improve implant integration, especially in compromised bone conditions.

Purpose of the Study:

• To develop and evaluate an injectable, self-assembling peptide nanofiber interface for enhancing implant biomechanical stability and accelerating bone formation.
• To assess the osteoinductive, adhesive, and antimicrobial properties of the peptide amphiphile gel.
• To compare the osseointegration and biomechanical performance of the nanofiber interface against a standard sand-blasted, large-grit, acid-etched (SLA) surface in a rabbit model.

Main Methods:

• Fabrication of a multifunctional, injectable gel from self-assembling peptide amphiphiles.
• Application of the nanofiber interface in the osteotomy site of custom titanium implants in a rabbit model.
• Evaluation of osseointegration using micro-computed tomography (micro-CT) for bone-to-implant contact (BIC) and bone volume/total volume (BV/TV) at 3 and 5 weeks.
• Assessment of biomechanical stability via reverse torque testing at 5 weeks.

Main Results:

• Implants with the nanofiber interface showed significantly superior osseointegration at 5 weeks compared to SLA-treated implants.
• Bone-to-implant contact (BIC) reached 58.7% with the nanofiber interface versus 50.5% for SLA (P < 0.001).
• Bone volume/total volume (BV/TV) was significantly higher at 51.8% for the nanofiber group compared to 42.6% for SLA (P < 0.001).
• Biomechanical stability was markedly improved, with the nanofiber group withstanding 53.2 N·cm of reverse torque, significantly higher than the 41.8 N·cm for the SLA group (P < 0.01).

Conclusions:

• The injectable peptide nanofiber interface effectively enhances bone-implant integration and provides superior biomechanical stability.
• This novel interface overcomes limitations of traditional coatings by preventing microdamage and acting as a conformal osteotomy liner.
• The approach shows promise for improving long-term clinical outcomes, particularly in patients with poor bone quality or high implant failure risk.