Biomimetic 3D printed PCL/TCP/GelMA scaffolds with improved osteogenesis and angiogenesis for non-load bearing applications

The strategy of biomimicry is crucial to effectively improve osteogenesis and angiogenesis for bone tissue engineering scaffolds, however, this approach remains challenging. In this study, we used a composite including PCL, TCP, and GelMA to mimic the heterogeneous bone composition. Meanwhile, hierarchical pores were successfully created through 3D printing, surface modification, and GelMA infiltration. Results showed that our 3D printing platform presented a high level of microstructural control of scaffolds and produced scaffolds with a porosity of 68.48 +/- 0.82%, an open porosity percentage of 97.81 +/- 1.44%, and a compressive strength of 2.68 +/- 0.03 MPa. In addition, triangular pores of 495.03 +/- 3.67 mu m, ECM-like pores of 126 +/- 31 mu m, and surface modified micro/nano roughness were observed from our 3D printed composite scaffolds leading to significantly improved hydrophilicity. Finally, in vivo results demonstrated that our 3D printed composite scaffolds exhibited enhanced osteogenesis and expedited transition from vascular formation and ECM deposition to mineralized bone formation, which was promising for clinical translations towards non-load bearing bone fixations.