3D Printing Polylactic Acid Porous Scaffolds for Bone Repair: Microstructure Optimization, In Vitro Degradation Behavior, and Cell Proliferation Performance

3D printing biodegradable porous polylactic acid (PLA) scaffolds is a promising approach to bone repair and should meet certain mechanobiological requirements, which are affected by the internal microstructures. In this work, the bionic interstructures of scaffolds, comprehensively synthetically considering variable pore geometrical features: geometry parameters (pore shapes and arrangement) and porosity, were simulated and optimized by finite-element analysis. It was found that the cross-sectional structure with circular pore arrangement, spherical pore and gradient aperture distribution, and the longitudinal-section gradient structure with small-size pores on the top and large-size pores on the bottom, contributed the lowest maximum stress and may be the optimal model of scaffolds. Based on the optimized model structure, PLA scaffolds were fabricated by the 3D printing method of fused filament fabrication (FFF) to investigate in vitro degradation behavior and cell proliferation performance. It revealed that this scaffold possessed suitable in vitro degradability and good biocompatibility, which could satisfy the needs of real histological engineering bone substitution.