Advancement of 3D biofabrication in repairing and regeneration of cartilage defects.

Three-dimensional (3D) bioprinting, an additive manufacturing technology, fabricates biomimetic tissues that possess natural structure and function. It involves precise deposition of bioinks, including cells, and bioactive factors, on basis of computer-aided 3D models. Articular cartilage injuries, a common orthopedic issue. Current repair methods, for instance microfracture procedure (MF), autologous chondrocyte implantation (ACI), and osteochondral autologous transfer surgery have been applied in clinical practice. However, each procedure has inherent limitation. For instance, MF surgery associates with increased subchondral cyst formation and brittle subchondral bone. ACI procedure involves two surgeries, and associate with potential risks infection and delamination of the regenerated cartilage. In addition, chondrocyte implantation's efficacy depends on the patient's weight, joint pathology, gender-related histological changes of cartilage, and hormonal influences that affect treatment and prognosis. So far, it is a still a grand challenge for achieving a clinical satisfactory in repairing and regeneration of cartilage defects using conditional strategies. 3D biofabrication provide a potential to fabricate biomimetic articular cartilage construct that has shown promise in specific cartilage repair and regeneration of patients. This review reported the techniques of 3D bioprinting applied for cartilage repair, and analyzed their respective merits and demerits, and limitations in clinical application. A summary of commonly used bioinks has been provided, along with an outlook on the challenges and prospects faced by 3D bioprinting in the application of cartilage tissue repair. It provided an overall review of current development and promising application of 3D biofabrication technology in articular cartilage repair.