Sacrificial-Template Fabrication of Orientation-Controlled Porous Titanium Lattices With Bioactive Surfaces

Porous titanium scaffolds for bone repair require coordinated control of pore architecture, mechanical behavior, and surface bioactivity. Here, we report a sacrificial-template route based on polymer 3D printing that produces orientation-controlled porous titanium scaffolds with hierarchical macro- and microporosity without direct metal additive manufacturing. Polylactic acid lattices printed by fused deposition modeling are infiltrated with a titanium powder slurry and then subjected to template removal and sintering. The process yields ortho-grid, tri-lattice, and quad-lattice structures with approximately 26% isotropic linear shrinkage, 65%-67% porosity, preserved geometric fidelity, and a relative density of approximately 95% in the sintered strut walls. Uniaxial compression tests reveal architecture-dependent behavior along the tested loading direction, whereas finite element simulations predict lower directional sensitivity under off-axis loading as strut-orientation diversity increases. Micro-arc oxidation forms a Ca-P-containing microporous oxide layer and improves cell spreading, proliferation, and alkaline phosphatase activity relative to untreated titanium scaffolds in vitro. In a rat calvarial defect model, uncoated titanium scaffolds achieve bone regeneration comparable to commercial porous tantalum, while micro-arc oxidation further enhances bone formation. Fabrication of cone augments and other non-prismatic geometries further demonstrates the adaptability of the approach to complex implant-relevant structures.