T. Vilella et al. Regenerating bone via multifunctional coatings: the blending of cell integration and bacterial inhibition properties on the surface of biomaterials. ACS Appl Mater Interfaces

Direct ink writing of TiNb scaffolds from elemental powders: towards superelastic and responsive bone-mimetic structures. Materials & Design 270 (2026) 116949. OPENA ACCESS.

doi: doi.org/10.1016/j.matdes.2026.116949

Abstract

Titanium-based alloys are essential for biomedical applications due to their low stiffness and biocompatibility, yet conventional manufacturing often faces challenges with phase segregation and high costs. This study optimized TiNb scaffolds produced via a Direct Ink Writing (DIW) using elemental powders, identifying an ink formulation with 75 wt% metallic loading as optimal for printability and shape fidelity. Sintering at 1400 °C was determined to be the critical condition for promoting effective diffusion and stabilizing the β-phase. Advanced TEM analysis revealed that this stabilization anchored by the formation of a chemically ordered superlattice structure, which inhibits diffusional transformations. Mechanically, the scaffolds exhibited a Young’s modulus matching human cortical bone, effectively addressing stress-shielding concerns. Furthermore, the TiNb scaffolds demonstrated a responsive behaviour to mechanical stimuli, showing superior time-dependent pseudo-creep and recovery kinetics when compared to pure Ti. Cyclic nanoindentation further identified a potential superelastic response inherent to the newly formed β-phase, characterized by high work and depth recovery ratios. In vitro assays with SaOS-2 osteoblastic cells confirmed that Nb incorporation significantly improves cell attachment and viability. These findings demonstrate DIW’s potential as a cost-effective method for manufacturing customized TiNb scaffolds with advanced microstructural and biomechanical properties for bone regeneration applications.