Advances and challenges in three-dimensional bioprinting of bone organoids: Materials, techniques, and functionalization strategies

Abstract

The use of three-dimensional (3D) bioprinting to construct bone organoids holds significant promise in bone tissue engineering due to its potential to replicate complex structures for research and regenerative medicine. This technology enables the creation of precise 3D structures through layer-by-layer deposition of bioinks guided by digital models. However, challenges remain in achieving functional bone organoids, especially in bioink design, vascularization, and cell viability preservation. To address these issues, various printing techniques such as extrusion, inkjet, light-curing, and microfluidic printing have been explored, but further advances are needed to improve the quality and functionality of printed bone organoids. This review assesses the current state of research on the application of 3D bioprinting techniques for the construction of bone organoids, focusing on the selection of bioinks, scaffold materials, and the role of cells and growth factors. Despite notable progress, significant challenges remain in optimizing the mechanical properties of bioinks, enhancing vascularization, and mimicking the dynamic physiological environment of bone tissue. The main objective of this study is to explore the technical challenges and opportunities in the construction of functional bone organoids through 3D bioprinting, aiming to provide insights into future directions for overcoming these obstacles and improving bone tissue regeneration applications.