Three-dimensionally printed polycaprolactone/beta-tricalcium phosphate scaffold was more effective as an rhBMP-2 carrier for new bone formation than polycaprolactone alone.

Recombinant human bone morphogenetic protein 2 (rhBMP-2) has been widely used in bone tissue engineering to enhance bone regeneration because of its osteogenic inductivity. However, clinical outcomes can vary depending on the scaffold materials used to deliver rhBMP-2. In this study, 3D-printed scaffolds with a ratio of 1:1 polycaprolactone and beta-tricalcium phosphate (PCL/T50) were applied as carriers for rhBMP-2 in mandibular bone defect models in dog models. Before in vivo application, in vitro experiments were conducted. Preosteoblast proliferation was not significantly different between scaffolds made of PCL/T50 and polycaprolactone alone (PCL/T0) regardless of rhBMP-2 delivery. However, PCL/T50 showed an increased level of the alkaline phosphatase activity and mineralization assay when rhBMP-2 was delivered. In in vivo, the newly formed bone volume of the PCL/T50 group was significantly increased compared with that of the PCL/T0 scaffolds regardless of rhBMP-2 delivery. Histological examination showed that PCL/T50 with rhBMP-2 produced significantly greater amounts of newly bone formation than PCL/T0 with rhBMP-2. The quantities of scaffold remaining were lower in the PCL/T50 group than in the PCL/T0 group, although it was not significantly different. In conclusion, PCL/T50 scaffolds were advantageous for rhBMP-2 delivery as well as for maintaining space for bone formation in mandibular bone defects.