Chitosan-Based Wound Dressings: Property Modulation, Fabrication Strategies, and Emerging Applications in Tissue Regeneration.

Chronic wounds are often difficult to heal because of multiple pathological barriers, including infection, vascular insufficiency, and immune imbalance, and therefore require highly effective dressings to promote repair. Chitosan (CS), a cationic polysaccharide derived from the deacetylation of chitin, has attracted broad attention in wound management because of its favorable biocompatibility, biodegradability, chemical modifiability, and intrinsic hemostatic and antibacterial activities. The therapeutic value of CS-based dressings does not depend solely on CS itself, but rather on their ability to target the dominant pathological barriers of different wound types through structural modification and formulation design. This review links the key pathological features of various chronic wounds with the functional requirements of CS-based dressings, and systematically summarizes how modification strategies such as catechol grafting, quaternization, carboxymethylation, and dynamic covalent crosslinking regulate the properties of CS, as well as the major fabrication platforms and formulation types, including crosslinked hydrogels, freeze-dried sponges, electrospun nanofibers, phase-inversion membranes, and solvent-cast films. Their effects on porosity, mechanical strength, moisture retention, and permeability are also analyzed. Finally, the review discusses the challenges facing CS-based dressings in standardization, scalable manufacturing, clinical translation, and regulatory evaluation, and highlights the need for greater emphasis on multifunctional smart design and the improvement of evidence quality in future research.