3D Bioprinting for Vascularized Tissue-Engineered Bone Fabrication

Vascularization in bone tissues is essential for the distribution of nutrients and oxygen, as well as the removal of waste products. Fabrication of tissue-engineered bone constructs with functional vascular networks has great potential for biomimicking nature bone tissue in vitro and enhancing bone regeneration in vivo. Over the past decades, many approaches have been applied to fabricate biomimetic vascularized tissue-engineered bone constructs. However, traditional tissue-engineered methods based on seeding cells into scaffolds are unable to control the spatial architecture and the encapsulated cell distribution precisely, which posed a significant challenge in constructing complex vascularized bone tissues with precise biomimetic properties. In recent years, as a pioneering technology, three-dimensional (3D) bioprinting technology has been applied to fabricate multiscale, biomimetic, multi-cellular tissues with a highly complex tissue microenvironment through layer-by-layer printing. This review discussed the application of 3D bioprinting technology in the vascularized tissue-engineered bone fabrication, where the current status and unique challenges were critically reviewed. Furthermore, the mechanisms of vascular formation, the process of 3D bioprinting, and the current development of bioink properties were also discussed.