The development of green, biomedical hydrogels using natural polymers is of great significance. From this viewpoint, guar gum (GG) has been widely used for hydrogel preparation; however, its mechanical strength and adhesion often cannot satisfy the biomedical application. Therefore, in the present study, gelatin and a cellulose nanocrystal (CNC) were first applied to overcome the defects of guar gum hydrogel. Dopamine was self-polymerized into polydopamine (PDA) on the gelatin chain at alkaline condition, and gelatin-polydopamine (Gel-PDA) further cross-linked with guar gum and CNC via the borate-didiol bond, intramolecular Schiff base reaction, and Michael addition. CNC not only interacted with guar gum using borate chemistry but also acted as a mechanical reinforcer. The obtained Gel-PDA+GG+CNC hydrogel had an excellent self-healing capacity, injectability, and adhesion due to the catechol groups of PDA. Moreover, dopamine introduction caused a significant increase in the anti-oxidant activity. This hydrogel was cyto- and hemo-compatible, which implies a potential usage in the medical field.
Keywords: borate; gelatin−polydopamine; guar gum; hydrogel; nanocellulose; self−healing.