3D printed porous PLGA/n-HA/MgP composite scaffolds with improved osteogenic and angiogenic properties

The osteogenic and angiogenic characteristics are crucial for the selection of bone substitute materials and structural design. This study proposed a porous PLGA/n-HA/MgP composited scaffold by printing of the poly (lactide-coglycolide) (PLGA), nano-hydroxyapatite (n-HA), and magnesium phosphate (MgP). The physicochemical properties, osteogenic activities, and pro-angiogenic impacts of porous 3D printed PLGA/n-HA scaffolds with variable MgP concentration were investigated. The results indicated that the presence of MgP in the composite promoted scaffold degradation and buffered the acidic environment induced by PLGA degradation. The highest pro-osteogenic activity has been observed in PLGA/n-HA/10% MgP (PH10M) group, which up-regulated BMP2 and RUNX2 factors in vitro and in vivo. Nevertheless, at a maximal ion release of 7.2 mmol/L, PLGA/n-HA/30% MgP (PH30M) marginally reduced the osteogenic differentiation of osteoblasts through the RANKL/OPG pathway. In vitro, PLGA/n-HA/20% MgP (PH20M) demonstrated superior migration, pro-angiogenic factor expression, and angiogenesis compared to other groups, and the histological investigation corroborated the improved angiogenesis in PH10M and PH20M. In conclusion, suitable MgP ratio shows the potential to improve the osteogenic and angiogenic properties of PLGA/n-HA-based composites in orthopedic applications.