A bilayer carbohydrate hydrogel spatiotemporally modulates the leucine-mTORC1 axis in macrophages to orchestrate wound immunity and regeneration.

The healing of infected wounds remains a significant clinical challenge, primarily due to persistent bacterial infections and dysregulated inflammation. In this work, we engineered an injectable bilayer hydrogel system (GHL//PCB) from carbohydrate polymers to spatiotemporally modulate macrophage metabolism and polarization via the leucine-mTORC1-HIF-1α axis. The lower layer, comprising methacrylated gelatin and dopamine-modified hyaluronic acid (GelMA/HA-DA), is loaded with leucine. This formulation activates mTORC1, stabilizes HIF-1α, and drives M1-like polarization, thereby conferring potent bactericidal efficacy against both Staphylococcus aureus and Escherichia coli. The upper layer, composed of aldehyde-modified Pluronic® F127 and carboxymethyl chitosan (PF127-CHO/CMCS), delivers the leucyl-tRNA synthetase inhibitor BC-LI-0186 to suppress mTORC1-HIF-1α signaling. This suppression promotes a metabolic shift toward oxidative phosphorylation and facilitates M2-like repolarization. Using a rat model featuring complete-thickness contaminated injuries, the GHL//PCB hydrogel sequentially eliminated bacteria, attenuated inflammation, enhanced collagen deposition, and accelerated re-epithelialization within 14 days. The hydrogel also demonstrated excellent injectability, tissue adhesion, biocompatibility, and hemocompatibility. Collectively, this work presents a carbohydrate-based biomaterial strategy that actively orchestrates the wound immune microenvironment through metabolic reprogramming, offering a promising and clinically translatable platform for the management of infected and chronic wounds.