Schematic presentation of the study design and scaffold construction. (A) Schematic Illustration of the study design with 3D bioprinted dual-factor releasing and gradient-structured MSC-laden constructs for articular cartilage regeneration in rabbits. Schematic diagram of construction of the anisotropic cartilage scaffold and study design. (B) A computer-aided design (CAD) model was used to design the four-layer gradient PCL scaffolding structure to offer BMS for anisotropic chondrogenic differentiation and nutrient supply in deep layers (left). Gradient anisotropic cartilage scaffold was constructed by one-step 3D bioprinting gradient polymeric scaffolding structure and dual protein-releasing composite hydrogels with bioinks encapsulating BMSCs with BMP4 or TGFβ3 μS as BCS for chondrogenesis (middle). The anisotropic cartilage construct provides structural support and sustained release of BMSCs and differentiative proteins for biomimetic regeneration of the anisotropic articular cartilage when transplanted in the animal model (right). Different components in the diagram are depicted at the bottom. HA, hyaluronic acid.
Cartilage injury is a common cause of joint dysfunction and existing joint prostheses cannot remodel with host joint tissue. However, it is challenging to develop large-scale biomimetic anisotropic constructs that structurally mimic native cartilage. In a new report on Science Advances, Ye Sun and a team of scientists in orthopedics, translational research and polymer science in China, detailed anisotropic cartilage regeneration using three-dimensional (3-D) bioprinting dual-factor releasing gradient-structured constructs. The team used the dual-growth-factor releasing mesenchymal stem cell (MSC)-laden hydrogels for chondrogenic differentiation (cartilage development). The 3-D bioprinted cartilage constructs showed whole-layer integrity, lubrication of superficial layers and nutrient supply into deeper layers. The scientists tested the cartilage tissue in the lab and in animal models to show tissue maturation and organization for translation to humans after sufficient experimental studies. The one-step, 3-D printed dual-factor releasing gradient-structured cartilage constructs can assist regeneration of MSC- and 3-D bioprinted therapy for injured or degenerative joints.