Hyaluronic Acid-Based Injectable Hydrogels for Dermal and Soft Tissue Engineering: From Polysaccharide Network Architecture to Structure–Property–Function Relationships

Injectable hydrogels are versatile polysaccharide-based biomaterials whose performance is governed by macromolecular network architecture and structure–property–function relationships. Among polysaccharides, hyaluronic acid (HA) is particularly relevant for dermal and soft tissue applications because of its biocompatibility, hydration capacity, and tunable viscoelastic behavior. This review critically examines HA-based injectable hydrogels, with emphasis on how polymer organization, crosslinking strategy, network topology, and hybridization influence injectability, mechanical behavior, degradation, and biological performance. Particular attention is given to rheological parameters, including storage and loss moduli, shear-thinning, and structural recovery, as key determinants of hydrogel functionality under mechanically dynamic tissue conditions. Conventional, dynamic, physical, enzymatic, and bio-orthogonal crosslinking strategies are discussed in relation to their effects on network stability and functional adaptability. Recent hybrid architectures incorporating secondary polymeric or particulate phases are further examined as strategies to modulate mechanical reinforcement, degradation behavior, and bioactivity. Overall, this review establishes a structure–property–function framework for understanding the design of HA-based injectable hydrogels and highlights network architecture and phase integration as central factors in the development of next-generation polysaccharide-based systems for dermal and soft tissue engineering.