Cartilage, as a shield at the end of the bones, has an elastic structure with no blood vessel and nerve, has very low feeding rate. . Thus, cartilage’s repair process is very complicated and most treatments applied on other tissues of human body, cannot applied for cartilage. Current therapies for treating cartilage, requiring invasive surgery. In this project, an injectable nanohybrid hydrogel with robust mechanical properties was developed based on Methacrylate Kappa-carrageenan (KaMA)-dopamine functionalized graphene oxide (GOPD) for soft tissue engineering, especially for cartilage. KaMA-GOPD hydrogels revealed shear-thinning behavior and injectability through interaction of active catechol groups of dopamine with other moieties in the structure of hydrogels. In addition, these interactions promoted mechanical properties of hydrogels, depending on the GOPD content. Noticeably, encapsulation of 20 wt.% GOPD significantly enhanced compressive strength (8-folds) and toughness (6-folds) of KaMA. Furthermore, the hybrid hydrogel consisting of 20 wt.% GOPD significantly reduced energy loss from 70% (at KaMA) to about 61%, after a two-cycle compression test, while significantly enhanced recovery of the KaMA structure. Reinforcing the KaMA with 20 wt.% GOPD resulted in enhanced fibroblast proliferation (2.5-times) and spreading (5.7 times) after 5 days of culture. Then, KaMA-GOPD hydrogel were used in 3Dbioprinter as input material for cartilage regeneration. With optimizing all parameters in 3Dbioprinting, ear scaffold was successfully printed. Based on these findings KaMA-GOPD hydrogels could be used for cell delivery through the injection process and applied as a suitable bio-ink for 3Dbioproiting process.
