Bacterial nanocellulose-reinforced gelatin methacryloyl hydrogel enhances biomechanical property and glycosaminoglycan content of 3D-bioprinted cartilage.

Tissue-engineered ear cartilage scaffold based on three-dimensional (3D) bioprinting technology presents a new strategy for ear reconstruction in individuals with microtia. Natural hydrogel is a promising material due to its excellent biocompatibility and low immunogenicity. However, insufficient mechanical property required for cartilage is one of the major issues pending to be solved. In this study, the gelatin methacryloyl (GelMA) hydrogel reinforced with bacterial nanocellulose (BNC) was developed to enhance the biomechanical properties and printability of the hydrogel. The results revealed that the addition of 0.375% BNC significantly increased the mechanical properties of the hydrogel and promoted cell migration in the BNC-reinforced hydrogel. Constructs bioprinted with chondrocyte-laden BNC/GelMA hydrogel bio-ink formed mature cartilage in nude mice with higher Young's modulus and glycosaminoglycan content. Finally, an auricle equivalent with a precise shape, high mechanics, and abundant cartilage-specific matrix was developed in vivo. In this study, we developed a potentially useful hydrogel for the manufacture of auricular cartilage grafts for microtia patients.