β-TCP–polylactide composite scaffolds with high strength and enhanced permeability prepared by a modified salt leaching method

A modified particulate leaching method for fabrication of strong calcium phosphate–polymer composite scaffolds with improved pore interconnectivity is reported. The scaffolds were produced by mixing precompacted composite granules (β-TCP with 40 vol% PLA) of different size and density with salt particles followed by high pressure consolidation (at room temperature or 120 °C) and porogen dissolution. The scaffoldsʹ compressive strength and Darcyʹs permeability were found to be inversely related and to be strongly dependent on the processing parameters. The use of precompacted granules instead of the loose β-TCP–PLA powder allowed us to increase permeability by three orders of magnitude while maintaining load bearing characteristics. Scaffolds with 50% porosity prepared from large (300–420 μm) composite granules of β-TCP–40 vol% PLA and salt porogen particles of comparable size exhibited the best combination of compressive strength (4–6 MPa) and permeability (1.3–1.6×10−10 m2) falling within the range of trabecular bone.