3D-Printed Triply Periodic Minimal Surface Scaffolds via Digital Light Processing for Enhanced Osteogenesis

Natural bone is a naturally mineralized material with a non-homogeneous porous structure, which is difficult to construct using conventional manufacturing methods. Triply periodic minimal surfaces (TPMS) have emerged as an excellent solution in recent years for constructing porous artificial bone structures, characterized by smooth surfaces, highly interconnected porous structures, and mathematically controllable geometries. In this work, digital light processing (DLP) printing technology was used to construct a non-homogeneous TPMS structure with strontium-doping 13-93 bioactive glass (Sr@BG) prepared by fusion method. The heterogeneous scaffolds were obtained by integrating high-strength I-wrapped package (I) and high-permeability Gyroid (G) units behaving a sufficient compressive strength of 5.8±0.6 MPa, a porosity of ∼63% and a permeability of 0.97 × 10−8 m2, which matched the microstructural parameters of cancellous bone. Meanwhile, the biomimetic structure and Sr doping could cooperatively promote the adhesion, proliferation and differentiation of bone mesenchymal stem cells (BMSCs). In addition, the osteogenic ability of IG scaffolds was verified in rabbit’s femoral condylar defect. In general, heterogeneous IG scaffolds possess desirable bioactivity and mechanical property which meet the functional and structural requirements of bone regeneration