3D bioprinting bone/cartilage organoids: construction, applications, and challenges.

Orthopaedic disorders, such as osteoporosis and osteoarthritis, impose substantial suffering upon an increasing population, driving demand for accurate disease models. Bone/cartilage organoids offer a promising solution by replicating complex 3D microstructures and multi-cellular niches, overcoming limitations of 2D models and animal experiments. 3D bioprinting, an additive manufacturing technology, enables the spatially precise deposition of cells and bioactive materials, facilitating efficient construction of organoids with enhanced structural fidelity. Therefore, this review specifically focuses on bone and cartilage organoids constructed using 3D bioprinting technologies. We summarize the prevailing 3D bioprinting techniques and biomaterials employed, critically analyze the unique advantages of bioprinting for creating these organoids, explore current technical challenges, such as standardization and scalability, and discuss future research directions. By addressing current progress and key issues in bioprinting bone/cartilage organoids, this review aims to accelerate their standardization and application as powerful platforms for multiscale disease modeling, drug screening, and regenerative medicine strategies. The translational potential of this article: Bone/cartilage organoids constructed via 3D bioprinting, through precise recapitulation of bone and cartilage tissue microenvironment and physiology, enable multiscale disease modeling from localized pathologies to systemic responses, despite persisting unresolved challenges in reproducibility and stability. This review highlights their clinical translational value and elucidates the driven role of 3D bioprinting in accelerating their clinical adoption, particularly in regenerative medicine.