New Insights into 3D Bioprinting of Cartilage: A Review on Recent Advances, Challenges, and Perspectives.

Cartilage is an avascular tissue with a limited capacity for self-regeneration. Traditional autologous cartilage transplantation is incapable of fulfilling the increasing demand for repair of various cartilage tissue lesions. The advent of 3D bioprinting technology provides an opportunity to repair articular cartilage defects through the construction of organized living structures composed of biomaterials and cells. This technology can mimic natural cartilage by allowing control of cell distribution, and the modulation of mechanical and chemical properties with high precision. This review provides insight into the current developments in 3D bioprinting for cartilage tissue engineering. Recent studies on 3D-bioprinted cartilage tissue constructs and various bioinks are highlighted. The advantages and limitations of commonly used natural, synthetic, and composite bioinks in terms of printability, mechanical properties, and biological performance in bioprinting of anatomically shaped constructs (nasal, auricle, knee, and tracheal cartilage) are discussed. Furthermore, outlooks and challenges of 3D bioprinting of complex constructs with variable mechanical and biological properties are provided. Based on recent progress, it is expected that 3D bioprinting will lead to improved 3D tissue-engineered constructs for regeneration and repair of cartilage tissue.