Polysaccharide-Based Biomaterials: Chemical Design and Advanced Dressings for Diabetic Chronic Wound Repair.

Diabetic foot ulcers, the typical manifestation of diabetic chronic wounds, pose a severe global public health burden. Such lesions feature a hyperglycemic microenvironment, sustained inflammation, severe oxidative stress, defective angiogenesis and recurrent bacterial infection, collectively leading to protracted healing, high relapse rates and elevated amputation risk. Natural polysaccharides, biocompatible and biodegradable macromolecules with low immunogenicity, exhibit versatile biofunctions including antibacterial, antioxidant, anti-inflammatory, pro-angiogenic and immunomodulatory effects via regulating macrophage polarization, making them ideal building blocks for wound repair dressings. Polysaccharide-derived dressings can absorb wound exudate, sustain moist microenvironments, eliminate reactive oxygen species, suppress pathogens/biofilms and facilitate angiogenesis and re-epithelialization to accelerate wound closure. Nevertheless, their clinical translation is restrained by ambiguous structure-activity relationships, inconsistent batch activity, undefined molecular mechanisms and bottlenecks in scalable manufacturing. This review first briefly summarizes the pathological traits of diabetic chronic wounds, classifies therapeutic polysaccharides by plant, animal and microbial origins, and emphatically discusses the chemical design, fabrication strategies, functional merits and underlying therapeutic mechanisms of multi-form polysaccharide biomaterials (hydrogels, nanofibers, microneedles, aerogels, etc). It delivers chemical-level theoretical guidance and process references for the subsequent fundamental investigation and industrial transformation of diabetic wound-healing biomaterials.