An injectable mechanically robust hydrogel of Kappa-carrageenan-dopamine functionalized graphene oxide for promoting cell growth.

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. 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. Based on these findings, KaMA-GOPD hydrogel could be used for cell delivery through the injection process and applied as a suitable bio-ink for 3D-bioproiting process.