Biomedical Hydrogels Based on Natural Polysaccharides: Structural Design

Hydrogels have gained prominence as a class of biomaterials in biomedicine due to their excellent biocompatibility, biodegradability, and high water retention. Among them, hydrogels derived from natural polysaccharides sourced from plants, animals, and microbes are attracting growing interest due to their renewable nature, low toxicity, low immunogenicity, and diverse functional properties. While several recent reviews have addressed polysaccharide-based hydrogels, they have largely focused on isolated aspects-such as 3D bioprinting formulations, double-network mechanical reinforcement, rheological behavior, or single-source polysaccharides-without establishing an integrated framework that links raw material selection, structural diversity, chemical modification, and crosslinking design to clinical translation. This review distinguishes itself by providing a systematic, end-to-end perspective that spans from the structural diversity of plant- and microbe-derived polysaccharides through recent advances in chemical modification and novel cross-linking strategies, to the fine-tuning of physicochemical properties for enhanced therapeutic outcomes. This article provides an overview of the progress made in the emerging biomedical applications and material design of natural polysaccharide hydrogels in terms of raw material selection, chemical modification, cross-linking mechanisms, and functional utilization. It aims to fully explore the potential of these materials and promote integration into advanced biomedical practices.