Spatially Programmed Hydrogel Dressing Enables Phase-Matched Sequential Ion Release for Accelerated Severe Burn Repair

Severe burn wounds with excessive exudation and high infection risk disrupt all four healing phases, requiring antibacterial, exudate-managing, and phase-specific strategies to drive wound contraction and tissue regeneration. Herein, we develop a spatially programmed hydrogel dressing (SPHD) via confined layer-by-layer photopolymerization, with Ga3+ and Fe3+ ions layer-specifically immobilized to enable chelation- and spatially guided programmable release with phase-matched kinetics. Abundant hydrophilic groups and dynamic catechol-boronate ester network render the hydrogel high swelling capacity, resilience, self-healing, and strong tissue adhesion. Its pH/temperature dual responsiveness enables adaptation to wound microenvironmental changes through reversible metal coordination and polymer conformational transitions. Hierarchically designed layers yield release kinetics aligned with healing phases, the inner layer rapidly releases Ga3+ within 16 h to suppress infection during the inflammatory phase, whereas the outer layer sustains Fe3+ release over 96 h, activating prolyl hydroxylase and promoting collagen synthesis and angiogenesis in the proliferative phase. Molecular dynamics simulations elucidate ion-specific diffusion barriers and mechanisms underlying phase-matched release. In murine deep second-degree burn model, SPHD accelerates wound closure to 96% in 12 days, enhancing epidermal barrier recovery and neovascularization. This work defines a paradigm for programmable wound management, offering a versatile platform extendable to regenerative medicine.