Ionic substitution through bredigite doping for microstructure and performance adjustment in DLP 3D-printed TPMS porous HA bone scaffolds

Abstract

Hydroxyapatite (HA) is widely used in bone scaffold development, but still faces problems of forming difficulty, slow degradation, and limited biological performance. In this study, triply periodic minimal surface (TPMS) porous HA scaffolds were prepared using desktop-level DLP and then doped with bredigite (BR) to enhance their performance through ion substitution to adjust microstructure. The DLP-prepared scaffolds displayed intricate curved surface porous structure, and their micro-porosity decreased while grain size increased with sintering holding time. During sintering, Mg2+ from BR substituted Ca2+ in HA, forming new secondary phases, which slightly decreased grain size while significantly increased micro-porosity. These factors slightly reduced mechanical properties while significantly enhanced degradation. The rapid release of inorganic active ions from BR and new phases enhanced the biomineralization and cell response. This study demonstrated the potential of using desktop-level DLP to construct complex porous ceramic scaffolds and using ion substitution to modulate their microstructure and performance.