3D-printed PCL/bioglass (BGS-7) composite scaffolds with high toughness and cell-responses for bone tissue regeneration

CaO-SiO₂-P₂O₅-B₂O₃ bioglass (BGS-7) showed highly bioactive properties including osteoconductivity and good mechanical strength, but it has extremely brittle property. In this study, we developed a composite scaffold, which is incorporated into poly(ε-caprolactone)(PCL), to overcome the mechanical disadvantage of the bioglass scaffold. The composite scaffolds were fabricated with a microscale porous mesh structure using a 3D melt-printing process. Surface topographical images demonstrated that the bioglass particles were distributed homogeneously throughout the composite scaffolds. The mechanical properties (compression and three-point bending test) of the composite scaffolds showed the toughness of the composite scaffolds was significantly improved compared to that of the pure bioglass scaffold with a similar porosity. We characterized the in vitro biological properties of the pure PCL, BGS-7, and composite scaffolds using MC3T3-E1 cells. As the weight fraction of bioglass increased, the cell proliferation and osteogenic activities significantly increased owing to the enhanced hydrophilic property, protein absorption, and precipitation of calcium phosphate from the bioglass. However, for the high weight fraction of bioglass (60 wt%) in the composite scaffold, the toughness was significantly lower than that of the composite scaffold (40 wt%). Based on these results, the appropriate concentration (40%) of the BGS-7 in the composite showed meaningful bioactivities and toughness.