Study on the Formation of Bone Printed Scaffolds and Vascular Networks in 3D Bioprinting / 中华骨科杂志

ABSTRACT

Globally, more than 2 million bone grafts are performed every year for bone defects in orthopedics, neurosurgery, and dental procedures. Current treatment options include the use of grafts of human, animal or synthetic origin. In this case, autograft is the current gold standard. However, its quantity is limited, a second wound(donor site) needs to be created, and the risk of infection, pain, and morbidity increases. In recent years, the rise of tissue engineering and 3D bioprinting has provided a new idea for treating bone defects in patients. 3D bioprinting is a branch of the applications of "additive manufacturing" in biological tissue engineering. It can precisely control cells, personalize macro and micro structures as needed, and can be used in bone regeneration applications. The establishment of osteoblast scaffolds is the basis of 3D bioprinting, and hydrogels suitable for the growth of bone and cartilage are the basis of scaffold research. For this reason, domestic and foreign scholars have developed and researcheda variety of hydrogel scaffolds, and they have found that mixed hydrogels with multiple biological materials have more advantages than single-material hydrogels. For example, hydroxyapatite, alginate or hyaluronic acid is used as the main component to mix several or more bioprinting materials, and 3D printed bone scaffold formed after combining the required cells can promote bone growth and differentiation better than traditional scaffolds. As the printed structure becomes thicker, the diffusion of nutrients and oxygen becomes more and more difficult. This is especially true in the reconstruction of bone tissue and it is necessary to create an interconnected and effective vascular network. Therefore, the formation of blood vessels in the stent is indispensable. This article mainly reviews the step-by-step research progress of bone printing scaffold materials and vascular network formation in 3D bioprinting.