Spontaneous Gelation of Adhesive Catechol Modified Hyaluronic Acid and Chitosan

Spontaneously formed hydrogels are attracting increasing interest as injectable or wound dressing materials because they do not require additional reactions or toxic crosslinking reagents. Highly valuable properties such as low viscosity before external application, adequate filmogenic capacity, rapid gelation and tissue adhesion are required in order to use them for those therapeutic applications. In addition, biocompatibility and biodegradability are also mandatory. Accordingly, biopolymers, such as hyaluronic acid (HA) and chitosan (CHI), that have shown great potential for wound healing applications are excellent candidates due to their unique physiochemical and biological properties, such as moisturizing and antimicrobial ability, respectively. In this study, both biopolymers were modified by covalent anchoring of catechol groups, and the obtained hydrogels were characterized by studying, in particular, their tissue adhesiveness and film forming capacity for potential skin wound healing applications. Tissue adhesiveness was related to o-quinone formation over time and monitored by visible spectroscopy. Consequently, an opposite effect was observed for both polysaccharides. As gelation advances for HA-CA, it becomes more adhesive, while competitive reactions of quinone in CHI-CA slow down tissue adhesiveness and induce a detriment of the filmogenic properties.

Automated summary

Spontaneously formed hydrogels are highly sought after for their potential applications in injectable or wound dressing materials without additional reactions or toxic crosslinking reagents. This study focuses on the covalent modification of hyaluronic acid (HA) and chitosan (CHI) with catechol groups, and the evaluation of their tissue adhesion and film forming capacity. The results show that the adhesiveness of HA-CA hydrogel increases with gelation, while the competitive reactions of quinone in CHI-CA hydrogel slow down tissue adhesion and impair filmogenic properties.