3D Bioprinting: New Directions in Articular Cartilage Tissue Engineering.

Bioprinting is a growing field with significant potential for developing engineered tissues with compositional and mechanical properties that recapitulate healthy native tissue. Much of the current research in tissue and organ bioprinting has focused on complex tissues that require vascularization. Cartilage tissue engineering has been successful in developing de novo tissues using homogeneous scaffolds. However, as research moves toward clinical application, engineered cartilage will need to maintain homogeneous nutrient diffusion in larger scaffolds and integrate with surrounding tissues. Bioprinting techniques have provided promising results to address these challenges in cartilage tissue engineering. The purpose of this review was to evaluate 3D extrusion-based bioprinting research for developing engineered cartilage. Specifically, we reviewed the potential impact of 3D bioprinting on nutrient diffusion in larger scaffolds, development of scaffolds with spatial variation in cell distribution or mechanical properties, and cultivation of more complex tissues using multiple materials. Finally, we discuss current limitations and challenges in using 3D bioprinting for cartilage tissue engineering and regeneration.