3D-Printed OsteoFlux Scaffolds with Radially Graded TPMS Structures

In native bone, the transition from dense cortical bone to porous cancellous bone reflects a spatial coordination between mechanical support and mass transport. Inspired by this structural heterogeneity, this study proposes an OsteoFlux (OF) scaffold featuring a radially graded TPMS structure together with a corresponding 3D printing strategy. Specifically, a biomimetic TPMS scaffold design integrating a continuous pore-size gradient with an explicit gradient position constraint was developed. Fluid-structure interaction (FSI) simulations investigating the effects of TPMS topology and gradient parameters on scaffold mechanical and transport performance were performed. The results indicated that the OF scaffold (a Gyroid (G-type) scaffold with an 800-400 μm radial pore-size gradient) achieved the most favorable combination of mechanical stability and fluid transport performance. Finally, an experiment optimizing the BCP slurry system and digital light processing (DLP) printing parameters was conducted. The fabricated OF scaffold exhibited a compressive strength of 3.25 MPa, a compressive modulus of 172.55 MPa, and a permeability of 4.17 × 10-9 m2. In vitro biological evaluation demonstrated favorable cytocompatibility, along with enhanced osteogenic differentiation and matrix mineralization of mBMSCs under scaffold-conditioned culture conditions. These findings demonstrate that the proposed OF scaffold provides an effective strategy for enhancing the overall performance of porous ceramic scaffolds.