Wounds caused by trauma, burns, diabetes, and surgery have threatened human health, and wound management has become a serious clinical challenge and economic burden. Collagen-based hydrogels have good biological activity, biocompatibility, and biodegradability, which make them have broad application prospects as wound dressings in different stages of wound healing and different types of wound healing. In this paper, the advantages and composition characteristics of collagen-based hydrogel dressings and their function mechanism in different wound healing processes such as hemostasis, inflammatory, proliferation, and remodeling are systematically reviewed. To summarize, the main molecular mechanisms of collagen-based hydrogel dressings include the provision of abundant nutrients at various stages, modulation of related cytokines (e.g., CD34, bFGF, and CTGF), inducement of signaling pathways (such as TGF-β/Smad, PI3K/Akt/mTOR), and promotion of the synthesis of ECM components, especially collagen. Thus, throughout the wound healing process, collagen-based hydrogel dressings can accelerate wound hemostasis, reduce inflammation, promote cell proliferation (especially of fibroblasts), aid in angiogenesis, enhance collagen synthesis, accelerate granulation tissue formation and re-epithelialization, and remodel the cytoplasmic matrix, ultimately leading to wound closure. Furthermore, this review discusses the existing problems in clinical application and scale production and outlines the future of development directions in the researches of collagen-based hydrogel dressings combining innovative wound treatment technologies, preparation technologies, and structural design methods, in order to inspire more new advancement and progress.

Mycelium has emerged as a promising bio-based material for the development of sustainable leather alternatives, driven by the increasing demand for eco-friendly materials. This work explores the crosslinking mechanism of mycelial leather alternatives treated with genipin tanning, focusing on the interactions between genipin and mycelium fibers. Genipin tanning agent interacts with nitrogen-containing groups and carboxyl groups in mycelial polysaccharides, inducing conformational changes in glycosides and increasing the thermal and structural stability of the mycelial leather alternative. Moreover, the synergistic effect of genipin tanning and glycerol fatliquoring resulted in a more organized and compact structure, with mycelial fibers tightly interwoven. The mycelial leather alternative demonstrated a tensile strength of 6.1 MPa, an elongation at break of 73.1%, as well as excellent thermal stability. The observed improved physical properties were attributed to the crosslinking of genipin with mycelial fibers and hydrogen bond formation between glycerol molecules and the hydroxyl groups on the fibers. Furthermore, the mycelial leather alternative demonstrated strong environmental performance, with more than 50% biodegradation in soil within 50 days. Its incineration produces fewer waste gases compared with traditional sheep leather. This work demonstrates the feasibility of using tanning methods to treat mycelial materials, providing valuable insights for advancing the development of leather alternatives.

In recent years, chromium-free tanning agents have gained widespread attention as eco-friendly and non-toxic alternatives in the leather industry. However, most commercially available options still suffer from poor stability under wet and heat conditions, lack of antimicrobial properties, and susceptibility to yellowing. Herein, pectin (P) was oxidized by sodium periodate (NaIO₄), green ethylene glycol diglycidyl ether (EGDE) was then used for graft modification, resulting in the successful synthesis of a multifunctional, green oxidized pectin-EGDE (OPE) as a chromium-free tanning agent. Characterization by FTIR, XPS, XRD, and ¹H NMR indicates that OPE has an oxidation value of 68%, epoxide value of 0.34 mol/100 g. Leather tanned with OPE demonstrates remarkably improved properties compared to traditional chromium-free tanning agents (F-90 and TWS), including high thermal stability (shrinkage temperature of 80.5 °C), superior softness (6.3 mm), tensile strength (13.3 MPa), and tear strength (57.3 N/mm). Moreover, the leather tanned with OPE also exhibits significant antimicrobial properties (inhibition zone diameters of 15 mm against S. aureus and 18 mm against E. coli), resistance to yellowing, and biocompatibility. Notably, the biodegradability of the wastewater from OPE tanned leather (BOD₅/COD ≥ 0.3) and its life cycle assessment confirm its unique environmental advantages. Overall, this work uses natural polysaccharides as the raw material to develop a green functional tanning agent, offering an innovative and sustainable solution for advancing the leather industry toward greener development.