Sequence-Programmed Peptide Nanozyme Hydrogel with Microenvironment-Responsive Dual Catalytic Activity for Infected...

Natural enzymes orchestrate complex biological processes through highly coordinated and multifunctional catalysis, yet their practical translation is limited by poor stability and environmental sensitivity. Here, we report a peptide-engineered nanozyme hydrogel that enables programmable, microenvironment-responsive catalytic switching in response to the wound microenvironment for active regulation of wound healing. Inspired by the catalytic motifs of natural hydrolases and oxidases, an amphiphilic peptide (C₁₆-GAVFFAHHGGEE) was rationally designed to coordinate Cu²⁺ and self-assemble into a β-sheet-rich nanofibrous hydrogel. The resulting system exhibits pH-dependent catalytic switching, functioning as an oxidase (OXD)-like nanozyme under acidic conditions to generate bactericidal reactive oxygen species for localized antibacterial activity (K_m = 32.45 mM, vₘₐₓ = 0.61 µM s^-1), while transitioning to hydrolases (HYD)-like activity under alkaline conditions to hydrolyze prodrugs and modulate inflammatory responses (K_m = 888.15 mM, vₘₐₓ = 3.55 mM s^-1). Distinct from conventional nanozyme-based wound dressings that provide isolated or static functionalities, this system dynamically links catalytic activity with the evolving wound microenvironment, thereby enabling coordinated intervention in bacterial infection, redox imbalance, and inflammation. In vitro studies demonstrate high cytocompatibility and broad-spectrum antibacterial activity. In a diabetic infected wound model, the hydrogel achieved almost complete wound closure within 12 days, accompanied by enhanced re-epithelialization, reduced inflammation, collagen deposition, and angiogenesis. This work establishes a strategy for integrating environment-responsive, dual enzyme-mimetic catalytic switching within a single peptide-based material, offering a programmable platform for actively modulating complex wound healing processes. STATEMENT OF SIGNIFICANCE: Chronic infected wounds require biomaterials capable of dynamically adapting to complex and evolving pathological microenvironments; however, most existing nanozyme systems exhibit static or single-function catalytic behavior. Here, we report a sequence-programmed peptide nanozyme hydrogel that integrates switchable multienzyme-mimetic catalysis within a single self-assembled peptide sequence. By coordinating Cu²⁺ within a β-sheet nanofibrous network, the hydrogel achieves microenvironment-responsive catalytic switching between antibacterial peroxidase-like activity under acidic conditions and anti-inflammatory hydrolase-like activity under alkaline conditions. This work establishes a direct structure-function relationship between peptide molecular design, supramolecular assembly, and adaptive therapeutic performance. The study provides a structurally simple yet multifunctional biomaterial platform for active microenvironment modulation and offers new insights into the design of peptide-based catalytic biomaterials for wound healing and other biomedical applications.