A comprehensive study on rheological properties of photocrosslinkable gallol-metal complexed hyaluronic acid-based biomaterial inks

This study describes the development of bioadhesive hydrogels as biomaterial inks, which combine catechol chemistry and metal coordination using gallic acid and hyaluronic acid. By controlling the phase of gelation, the properties of hydrogels can be modulated through pH and Fe3+ ion concentrations, thus allowing for diverse coordination states within the polymeric network. The dual-crosslinking mechanism based on catechol-metal coordination and methacrylation improves the hydrogels' printability and facilitates adaptive swelling behaviour, which is crucial for in situ bioprinting. The developed hydrogels address the challenge of effective adhesion in moist environments such as human tissues, exhibiting rapid self-healing and wet adhesion properties. Our findings indicate that mono- and bis-complex hydrogels are optimal for printing, while bis- and tris-complex hydrogels offer higher stability, which is suitable for injection. However, tris-coordinated hydrogels have limited self-healing and adhesive properties due to excessive oxidative crosslinking over time. Overall, this work advances the potential application of hyaluronan-based hydrogels in biomaterial inks, stimuli-responsive hydrogels, and bioadhesive inspired by mussel byssus cuticle chemistry.