A hierarchically graded bioactive scaffold bonded to titanium substrates for attachment to bone

Area of Science:

• Biomaterials Engineering
• Orthopedic Research
• Tissue Engineering

Background:

• Developing advanced bone scaffolds is crucial for orthopedic applications.
• Titanium (Ti) and its alloys are widely used in orthopedic implants due to their biocompatibility and mechanical strength.
• Hierarchical porous structures can mimic natural bone architecture, potentially improving osseointegration and bone regeneration.

Purpose of the Study:

• To fabricate and characterize a novel Ti-based hierarchical porous scaffold anchored to Ti substrates.
• To evaluate the mechanical properties, bioactivity, and osteoinductivity of the developed scaffold.
• To assess the scaffold's potential for promoting new bone growth and integration.

Main Methods:

• Synthesized hydroxyapatite--calcium carbonate-Ti three-layer spheres.
• Applied a modified plasma spraying process and anodic oxidation treatment.
• Characterized scaffold porosity, pore size distribution (macro-, micro-, nano-), and graded structure.
• Evaluated mechanical properties (Young's modulus, bonding strength).
• Assessed bioactivity via simulated body fluid immersion.
• Investigated in vitro cellular response with primary osteoblasts.
• Assessed osteoinductivity through intramuscular and bone implantation studies.

Main Results:

• Fabricated hierarchical porous scaffolds with >70% porosity and interconnected macropores (100-350 μm), pores (0.2-90 μm), and nanopores (~100 nm).
• Achieved graded structures with bioactive TiO(x) on the surface transforming to metallurgy-bondable Ti at the bottom.
• Demonstrated mechanical properties similar to natural bone with strong bonding strength to Ti substrates.
• Observed rapid formation of a bone-like apatite layer in simulated body fluid.
• Showed good cellular compatibility and regulation of osteoblast gene expression in vitro.
• Exhibited high osteoinductivity and facilitated new bone growth with strong bonding in vivo.

Conclusions:

• The developed Ti-based hierarchical porous scaffold demonstrates excellent biocompatibility, bioactivity, and mechanical properties.
• The scaffold's unique hierarchical and graded structure promotes rapid apatite formation, enhances osteoblast function, and facilitates robust new bone regeneration and integration.
• This novel scaffold holds significant promise as an advanced material for orthopedic applications, particularly for bone defect repair and spinal fusion.