Modified high-viscosity chitosan hydrogel for seawater immersion wound healing

Seawater immersion wounds carry high health risks owing to seawater's high-salt, ‌hypertonicity and diverse bacteria, and current therapies are limited and nonspecific, posing clinical challenges. In this study, high-viscosity chitosan (HVCS, viscosity >1000 mPa·s) from Antarctic krill shells was used as the matrix, glutamate as a molecular bridge linked dopamine and HVCS; high-viscosity dopamine-glutamate-chitosan (DGCS) was synthesized via amide bond-based covalent networks. DGCS inherits the rapid gel-forming ability of HVCS while showing its excellent favorable adaptability to seawater immersion wound surfaces. The introduction of dopamine and glutamic acid endows DGCS with more prominent mechanical properties and biological activities, including cell proliferation-promoting, antibacterial, and anti-inflammatory effects, and particularly inhibits the growth of specific Gram-negative pathogenic bacteria such as Vibrio vulnificus and Vibrio parahaemolyticus in vitro. More importantly, in seawater immersion wound rat models, DGCS hydrogel outperforms commercial chitosan dressings and silvadene in regulating wound inflammation, promoting collagen deposition, angiogenesis and healing. In conclusion, DGCS integrates antibacterial, anti-inflammatory and pro-healing functions, offering an effective multifunctional strategy for seawater immersion wound treatment, realizing the high-value-added valorization of shrimp shell waste and expanding HVCS's application in wound dressings.