A Prussian blue nanozyme-reinforced dynamic hydrogel reprograms the oxidative microenvironment for functional skeletal muscle regeneration

Abstract Background Volumetric muscle loss (VML) leads to irreversible disability driven by extensive tissue loss and a hostile microenvironment with excessive reactive oxygen species (ROS), persistent pro-inflammatory macrophages, and fibrosis. This study aimed to develop a Prussian blue nanozyme-reinforced dynamic GelMA hydrogel capable of modulating the pathological microenvironment and promoting muscle regeneration and functional recovery after VML. Methods We engineered a photocurable, dynamic nanozyme hydrogel (GelMA-PPB; GelMA/PBA-MA/PVA/Prussian Blue) by integrating GelMA photopolymerization with a reversible boronate ester network (PBA-MA/PVA) and Prussian Blue nanozymes. Hydrogel properties were characterized. C2C12 assays evaluated cytocompatibility, migration, intracellular ROS (DCFH-DA), and myogenic differentiation (MyHC). RAW264.7 assays assessed macrophage polarization (M1/M2 markers) and cytokines (IL-6/IL-10). Efficacy was tested in a murine tibialis anterior VML model using histology, immunofluorescence, CatWalk gait analysis, and major-organ biosafety. Results GelMA-PPB formed a porous 3D scaffold with favorable swelling/degradation and good cytocompatibility. It reduced intracellular ROS, enhanced myoblast migration and differentiation, and shifted macrophages toward a pro-regenerative M2 phenotype with decreased IL-6 and increased IL-10. In vivo, GelMA-PPB attenuated inflammation and fibrosis, promoted endogenous myogenesis and fiber maturation, improved gait-related functional parameters, and showed no obvious systemic toxicity. Conclusions GelMA-PPB reprograms the oxidative–inflammatory niche to enable structural and functional recovery after VML. The Translational Potential of this Article GelMA-PPB is an injectable, in situ photocurable hydrogel designed for defect-conformal VML filling while actively suppressing ROS-driven inflammation and fibrosis to enhance functional recovery. This off-the-shelf platform may complement or reduce reliance on muscle flap transfer and is amenable to future scale-up and integration with pro-regenerative cues.