Enhancing Bone Repair with β-TCP-Based Composite Scaffolds: A Review of Design Strategies and Biological Mechanisms.

Abstract

It is reported that there are approximately 2.2 million bone graft procedures every year due to injuries, bone tumors, marginal bone defects, and aging of the population. However, the scarcity of natural donors and graft rejection make it difficult to adequately fulfill clinical demands for bone repair. While β-tricalcium phosphate (β-TCP) is a key material in bone tissue engineering, it remains insufficient for treating large bone defects. Therefore, researchers have started investigating the combination of β-TCP with other biomaterials to achieve improved clinical outcomes. Such composite scaffolds possess excellent biocompatibility and effectively provide structural support to promote cell adhesion, proliferation, and differentiation-thereby accelerating new bone tissue formation. This review examines β-tcp-based composite scaffolds for bone regeneration, analyzing design innovations and biological mechanisms, and bone repair principles-with a focus on cellular dynamics and microenvironmental regulation. The discussion valuates β-TCP's osteoconductive properties while addressing its clinical limitations in mechanical strength and degradation control. Additionally, it systematically elucidates the specific application of β-TCP-based composite scaffolds in bone repair. These include osteoinductive, osteogenic, osteoconductive and inflammatory regulation. Moreover, clinical translation progress is discussed, highlighting applications in craniomaxillofacial reconstruction and osteonecrosis management. Finally, we summarize that β-TCP composite scaffolds face challenges including poor mechanical strength, asynchronous degradation-regeneration, and manufacturing limitations. Future directions should focus on developing synchronously degradable materials and intelligent scaffolds via 4D printing and AI-optimized designs, and clinical translation systems to achieve precise bone regeneration.