Fabrication and Characterization of a Porous TiO2-Modified PEEK Scaffold with Enhanced Flexural Compliance for Bone Tissue Engineering.

Abstract

Bone pathologies are becoming increasingly prevalent with an aging population, often necessitating bone grafting procedures. The current gold standard for grafting uses autologous tissue; however, this approach carries limitations such as donor site morbidity. Consequently, there is a growing interest in alternative biomaterials. Polyetheretherketone (PEEK), a thermoplastic with bone-like mechanical properties, has shown promise, although its limited bioactivity remains a critical constraint. Various functionalization strategies have been employed to enhance the biological performance of otherwise inert materials. This study aims to develop a functionalized porous PEEK scaffold to improve bioactivity of the material, thereby promoting human osteoblast (HOB) adhesion, proliferation, and differentiation. PEEK scaffolds were fabricated using fused deposition modeling (FDM) (Apium P155), with a rectilinear pattern alternating at +45° and -45° angles between layers. This configuration generated an interconnected pore network with sizes ranging from ∼100 to 400 μm. The scaffolds were further coated with titanium oxide as an additional intervention to enhance bioactivity. Mechanical properties of both porous and solid constructs were evaluated according to ISO 178, a flexural testing standard for plastics. Results indicated that both porous scaffolds exhibited a 10-fold decrease in flexural modulus and were 10 times more flexible compared to the solid counterpart (p < 0.001). The mechanical properties of both porous scaffolds were consistent with values reported for trabecular bone, while the solid construct demonstrated a flexural modulus comparable to cortical bone. These findings suggest that the porous PEEK scaffold, both neat and titanium oxide-coated, possesses mechanical properties similar to bone in vivo, indicating its potential as a mechanically suitable biomaterial for bone grafting applications.