3D printing for bone repair: Coupling infection therapy and defect regeneration

The treatment of infected bone defects is a major clinical challenge, which requires the development of scaffolds to simultaneously eliminate infection and provide a suitable bioactive environment for bone growth. 3D printing offers a feasible solution to address this issue by producing patient-oriented bone tissue engineering scaffolds. Combined with clinical treatment protocols, 3D-printed products can shorten treatment time and maximize efficacy. In this review, various 3D printing techniques including stereolithography, two-photon polymerization, selective laser sintering, and extrusion-based printing were first introduced and representative examples of 3D-printed scaffolds for bone infection therapy and defect regeneration are provided. After discussing the treatment strategies against bone infection and strategies for bone repair, we propose design strategies of antibacterial and osteogenesis-active bifunctional scaffolds for the treatment of infected bone defects. Finally, current challenges in developing 3D printing techniques for bone tissue engineering scaffolds are summarized and future development directions for treating infected bone defects are proposed.