PLA-based bone tissue engineering scaffolds incorporating hydroxyapatite and bioactive glass using digital light processing

Bone tissue engineering (BTE) aims to repair bone defects using biocompatible materials with tailored geometries and pore structures, providing appropriate mechanical support and control over biodegradation kinetics to promote bone growth. In this study, we utilized digital light processing (DLP) 3D printing to fabricate scaffolds with varying pore sizes using polymer-ceramic slurries composed of polylactic acid (PLA) as the main polymer matrix, incorporated with hydroxyapatite (HA) and bioactive borate glass (BBG) at various ratios. We studied the effect of composition on rheological behavior, printability, mechanical properties, bioactivity, degradation rate, and biocompatibility. While HA increased viscosity and reduced printing accuracy, it also improved mechanical properties and bioactivity. BBG increased the hydrophilicity and shape fidelity of the scaffold. Both HA and BBG enhanced the compressive mechanical properties by reinforcing the polymer matrix with ceramic particles. To study the scaffold's bioactivity, samples were immersed in simulated body fluid for 4 weeks. Both ceramic additives enhanced the bioactivity of PLA scaffolds, evidenced by the formation of a secondary HA layer on the scaffold surface. Among the scaffolds studied, PLA-BBG exhibited the highest osteocyte viability, followed by PLA-HA and then plain PLA samples. Our findings highlight the potential of DLP 3D printing for the fabrication of tailored polymer-ceramic scaffolds for BTE and other biomedical applications.