Application of 3D Printing Technology in Bone Tissue Engineering: A Review

: Clinically, the treatment of bone defects remains a significant challenge, as it requires autogenous bone grafts or bone graft substitutes. However, the existing biomaterials often fail to meet the clinical requirements in terms of structural support, bone induction and controllable biodegradability. In the treatment of bone defects, 3D porous scaffolds have at-tracted much attention in the orthopedic field. In terms of appearance and microstructure, complex bone scaffolds created by 3D printing technology are similar to human bone. On this basis, the combination of active substances including cells and growth factors is more conducive to bone tissue reconstruction, which is of great significance for the personalized treatment of bone defects. With the continuous development of 3D printing technology, it has been widely used in bone defect repair as well as diagnosis and rehabilitation, creating an emerging industry with excellent market potential. Meanwhile, the di-verse combination of 3D printing technology with multi-disciplinary fields such as tissue engineering, digital medicine, and materials science has made 3D printing products with good biocompatibility, excellent osteo-inductive capacity and stable mechanical properties. In the clinical application of the repair of bone defects, various biological materials and 3D printing methods have emerged to make patient-specific bioactive scaffolds. The microstructure of 3D printed scaffolds can meet the complex needs of bone defect repair and support the personalized treatment of patients. Some of the new materials and technologies that emerged from the 3D printing industry's advent in the past decade successfully translated into clinical practice. In this article, we first introduced the development and application of different types of materials that were used in 3D bioprinting, including metal, ceramic materials, polymer materials, composite materials, and cell tissue. The combined application of 3D bioprinting and other manufacturing method used for bone tissue engineering are also discussed in this ar-ticle. Finally, we discussed the bottleneck of 3D bioprinting technique and forecasted its research orientation and prospect.