3D printing of bioceramic/polycaprolactone composite scaffolds for bone tissue engineering

Despite the emergence of three-dimensional printing techniques that has been considered useful for promoting the osteogeneicity through the precise fabrication of patient-specific bone grafts with porous structures, which could favor the ingrowth of neo-bone tissues, the lack of suitable biomaterials with appropriate printability is still an obstacle that needs to be addressed. Thermoplastic polymer incorporated with osteoconductive bioceramics was a suitable biomaterial regarding to its good printability, biocompatibility and biodegradability. Unfortunately, the hydrophobic nature of synthetic polymers failed to form stable interfacial interactions with hydrophilic bioceramics, and hence restricted its uses in the application of bone tissue engineering. Thus, the aim of this study was to assess the reinforcement effect of polydopamine on the interfacial interaction between the thermoplastic polymer/bioceramic composite. The mechanical strength, hydrophilicity, and degradability of the composite porous scaffolds fabricated by a fused deposition modeling (FDM) based 3D printer were assessed. Moreover, the proliferation and differentiation of mesenchymal stem cells cultured on the scaffolds were examined. The results revealed that the compressive modulus of the polydopamine-incorporated composite scaffolds was strengthened by 67-130% compared to the unmodified composite scaffold. Additionally, results obtained from in vitro cell culture experiments indicated that the presence of polydopamine could also favor the proliferation, alkaline phosphatase activity, and calcium deposition of mesenchymal stem cells. The proposed route could be considered as a candidate strategy for developing three-dimensional printable composite materials for applications of bone regeneration.