Three-dimensional bioprinting of articular cartilage using silk fibroin–gelatin bioink

The self-healing of the articular cartilage lesions is difficult since it has a restricted self-healing capacity. However, surgical interventions have been implemented in osteoarthritis patients with limited success. Tissue-engineered cartilage can be used to address such issues. Over the years, researchers have employed three-dimensional bioprinting strategies for cartilage reconstruction. Although this technology potentially will enable researchers to fabricate the complex architecture of articular cartilage, there are quite a few hurdles yet to be addressed. A significant challenge is the selection of an ideal bioink formulation, which would encapsulate the cells without any cytotoxicity and demonstrate specific properties to be categorized as “bioprintable.” Most known biomaterials, either used alone or in combination, suffer from certain disadvantages; therefore the quest for an appropriate bioink for cartilage bioprinting is still on. In this chapter, we highlight the use of a combination of two protein-based biomaterials: (1) silk fibroin (SF), and (2) gelatin (G) for bioink development. Concerning the bioink formulation, we emphasize the various crosslinking strategies to prepare the SF–G bioink and the essential characteristics of the resultant ink before bioprinting. Lastly, we provide insight into the essential postbioprinting evaluation of the constructs and summarize the current challenges and future perspectives that could serve as a foundation for further research in this field.