Dual-Engineered Hydrogels from Shared Precursors: Injectable Conformability and Janus Asymmetric Adhesion for Emergency Hemostasis and Accelerated Wound Healing

Dual-engineered hydrogels fabricated from shared precursors (gelatin (GA), oxidized sodium alginate (OSA), folic acid (FA), and cerium(III) ions (Ce³⁺)) are developed for rapid hemostasis and accelerated wound healing. The injectable hydrogels achieve conformal adaptation to irregular wounds via shear-thinning behavior and sustain FA/Ce³⁺ release, while the Janus hydrogels feature asymmetric adhesion (hydrophilic-hydrophobic interfaces) for instant tissue sealing and contamination resistance. Both hydrogels demonstrate exceptional hemostatic efficiency, achieving clotting times <60 s <i>in vitro</i> and reducing <i>in vivo</i> hemorrhage by >90% in a rat liver injury model (hemostasis time <30 s). Enhanced by dynamic Schiff base bonds, π-π stacking, and Ce³⁺ chelation, these hydrogels exhibit robust wet adhesion, antioxidant activity (reactive oxygen species scavenging >90%), and biocompatibility (cell viability >98%). In a full-thickness skin wound model, they accelerate closure (94.3% at 14 days vs 76.2% control) by promoting macrophage polarization (M1-to-M2 transition), angiogenesis (CD31/α-SMA upregulation), and collagen remodeling. The injectable variant fully occupies wound cavities to optimize fibroblast migration, whereas the Janus design prevents external contamination via hydrophobic shielding. This dual design strategy for developing hydrogels with bifunctional properties significantly enhances their applicability for wound dressing purposes, offering a versatile and multifaceted platform for managing complex wounds.