Osteoimmune-modulating and BMP-2-eluting anodised 3D printed titanium for accelerated bone regeneration

Area of Science:

• Biomaterials Engineering
• Orthopaedic and Dental Implantology
• Cellular and Molecular Biology

Background:

• 3D printing of titanium (Ti) offers personalized implants, but surface topography's role in cellular interaction and growth factor delivery is understudied.
• Controlled surface features are crucial for guiding implant integration with bone tissue.

Purpose of the Study:

• To investigate how titania nanotube (TiNT) surface topography on 3D printed Ti implants affects immune cell interactions.
• To assess the capacity of TiNTs to deliver bioactive growth factors for enhanced osseointegration.

Main Methods:

• Anodic growth of TiNT layers with controlled pore diameters (21-130 nm) on 3D printed Ti surfaces.
• Analysis of immune biomarker profiles (gene and protein levels) to determine macrophage activation (M1 vs. M2).
• In vitro bone mineralization studies and assessment of recombinant human bone morphogenetic protein-2 (BMP-2) release and bioactivity from TiNTs.

Main Results:

• Smaller TiNT pores (<100 nm) promoted M1-like macrophage activation, while larger pores (>100 nm) promoted M2-like activation.
• Pore diameter significantly impacted in vitro bone mineralization.
• Sucrose enabled the most sustained release of bioactive BMP-2 from TiNTs, retaining its efficacy.

Conclusions:

• TiNT surface topography can modulate immune responses and bone mineralization.
• Controlled, sustained release of BMP-2 from TiNTs on 3D printed Ti implants shows potential for improved osseointegration.
• This approach may enhance clinical outcomes for custom orthopaedic and dental implants.