Chondrocyte-laden gelatin/sodium alginate hydrogel integrating 3D printed PU scaffold for auricular cartilage reconstruction.

Clinically, modified autologous rib cartilage grafts and commercial implants are commonly used for intraoperative repair of auricular cartilage defects caused by injuries. However, scaffold implantation is often accompanied by various complications including absorption and collapse, resulting in undesirable clinical outcomes. Three-dimensional printed auricular cartilage scaffolds have the advantage of individual design and biofunctionality, which attracted tremendous attention in this field. In this study, to better simulate the mechanical properties of auricular cartilage, we tested PU treated by ultrasonication and high temperature for 30 min (PU-30) or 60 min (PU-60). The results indicated that the compression modulus of PU-30 was 2.21-2.48 MPa, which similar to that of natural auricular cartilage (2.22-7.23 MPa) and was chosen for subsequent experiments. And the pores of treated PU were filled with a gelatin/sodium alginate hydrogel loaded with chondrocytes. In vivo analysis using a rabbit model confirmed that implanted PU-30 scaffold filled with chondrocytes contained hydrogel successfully integrated with normal auricular cartilage, and that new cartilage was generated at the scaffold-tissue interface by histological examination. These findings illustrate that this engineered scaffold represents a potential strategy for repair of ear cartilage damage in clinical.