Hierarchical assembly of traditional chinese medicine-based hydrogels for wound healing

Chronic wound healing represents a significant clinical challenge, requiring multi-target intervention strategies due to the complex pathological microenvironment. Traditional Chinese Medicine (TCM) has a long wound care history and TCM-based hydrogels have evolved from single- to multi-component designs. However, existing reviews primarily focus on preparation methods, lacking a systematic analysis of how the hierarchical assembly of TCM components influences hydrogel structure, properties, and wound healing efficacy via structure-activity relationships. This review proposes a novel component-number hierarchy, defined as a systematic analytical framework classifying TCM-based hydrogels by active component count and assembly logic. This framework stratifies systems into four progressive hierarchical levels: single-component, dual-component, multi-component, and formula-mimetic systems. Specifically, formula-mimetic systems are defined as hydrogel platforms that mimic TCM's "emperor-minister-assistant-courier" principle via rational hierarchical assembly of multi-components with well-defined roles, to replicate holistic multi-target synergistic effects in wound dressings. We summarize the driving forces for assembly, structural formation mechanisms, and key physicochemical properties across different hierarchical levels, and analyze how these properties govern functional performance at distinct stages of wound healing. By addressing current challenges and future directions, this review provides a theoretical basis and design principles for developing advanced intelligent TCM hydrogel dressings.