Comparative study of the bioactive PLGA/CaP composites: the influence of 3D structure on inflammatory and osteoinductive properties
We aimed to develop a composite poly (lactic-co-glycolic acid) (PLGA)/calcium phosphate nanoparticles scaffold with the optimal three-dimensional structure to provide an environment for bone tissue regeneration. Composite PLGA-based scaffolds with the inclusion of 15% hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) nanoparticles, as well as scaffolds with the addition of 15% xenogeneic bone chips, and with different pore diameters were prepared by a solvent casting with particle leaching method. Synthesized HA and β-TCP nanoparticles were characterized using x-ray phase analysis and atomic force microscopy. The scaffold morphology was studied with electron microscopy and energy dispersive x-ray spectroscopy. The scaffold biocompatibility, immunogenicity, inflammatory and osteoinductive properties were investigated in vitro using dental pulp stem cells (DPSCs), human lymphocyte culture, and RAW 264.7 mouse macrophage cells. Among the investigated samples, the PLGA/ β-TCP scaffold showed the highest osteoinduction, and the scaffold with 530 ± 56 μm average pore diameter demonstrated the highest expression of osteodifferentiation marker genes in DPSCs. Furthermore, the addition of nanoparticles into the polymer matrix led to the decrease in the expression of pro-inflammatory genes in macrophages. PLGA with 15% β-TCP and 530 ± 56 μm pore size had the best bioactivity among the tested scaffolds in vitro, and it could be considered as a potential candidate for bone tissue engineering applications.