The incidences with chronic wounds due to diabetes mellitus, obesity or reduced mobility are nowadays among the top medical challenges. Chronic wounds present multifactorial nature, which rendered the available single-factor directed wound dressing therapies low or non-effective. To overcome this drawback, we developed multifunctional thiolated chitosan-based hydrogels enzymatically crosslinked with the polyphenol chicoric acid as platforms for treatment of chronic wounds. Gelation was driven by thiol Michael addition reaction between quinone form of laccase-oxidized chicoric acid, herein used for the first time as a homobifunctional crosslinker and nucleophilic thiol groups of the thiolated chitosan. By using this approach, the gelation time was reduced more than twice and lower concentration of the crosslinking agent was used compared to reported enzymatically synthesized hydrogels using phenolic acids. Hydrogel platform with tunable physicochemical and bioactive characteristics were achieved by varying both the degree of thiolation and the concentration of chicoric acid. The hydrogel platform presents up to 600 % liquid uptake coupled with only 20 % weight loss after six days in physiological solution containing lysozyme. The hydrogels present good biocompatibility (&gt; 80% against human fibroblasts after seven days) and high antibacterial activity for the gram positive Staphylococcus aureusand the gram-negative Pseudomonas aeruginosa(4.5 and 5.5 logs respectively). The release of the antioxidant chicoric acid revealed the potential of hydrogels for scavenging the elevated detrimental amounts of reactive oxygen species in the chronic wound milieu. Chronic wound exudate ex-vivostudies confirm that the engineered hydrogels control myeloperoxidase (MPO) and matrix metalloproteinases (MMPs) activities.

Enzymatic synthesis of hydrogels based on thiolated chitosan and chicoric acid for chronic wound application

2019 Spring National Meeting

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