Optimization of hydroxyapatite-PEGDA slurry for vat polymerization: Microstructure and mechanical properties of 3D printed bioscaffolds

Vat polymerization has been employed to fabricate porous poly(ethylene glycol) diacrylate (PEGDA)/hydroxyapatite (HA) composite bioscaffolds and ceramic HA bioscaffolds with controlled geometry for bone tissue regeneration. UV-curable slurries were formulated using bimodal HA powder derived from bovine bones. A bimodal particle size distribution enhanced powder packing density and mechanical properties, ensuring effective sintering. Tartrazine (0.14 wt%) was incorporated as a photoabsorber to improve geometrical accuracy and the printability of complex bioscaffold architectures. Rheological analysis revealed viscosity dependence on solid content, with 50 wt% HA providing superior dispersion stability. Sintering at 1250 °C facilitated densification, achieving the highest compressive strength (4.7 MPa for G50 samples) and exhibiting the highest porosity (89% for G30 samples). Notably, the mechanical properties of both sintered and non-sintered samples were examined, revealing comparable results, thereby demonstrating the robustness of the developed materials and processes.