Atlas-Guided CD55-Enriched Neutrophil Extracellular Vesicles for Complement-Macrophage Modulation in Diabetic Wounds

Diabetic wounds are characterized by persistent inflammation and impaired immune resolution, yet the therapeutic translation of single-cell atlases into rational immunomodulatory strategies remains limited. Here, integration of diabetic-wound single-cell transcriptomic datasets identifies a neutrophil subpopulation enriched in cluster of differentiation 55 (CD55) with complement-regulatory and reparative features. Guided by this atlas-derived signature, activated neutrophil-derived extracellular vesicles (aNEVs) enriched in CD55 are generated under high-glucose and lipopolysaccharide stimulation and incorporated into a microbial transglutaminase-crosslinked gelatin hydrogel for localized delivery and protease-sensitive matrix remodeling. The resulting gelatin/aNEV composite hydrogel (Gel/aNEV) attenuates complement-associated inflammatory signaling, C3a production, oxidative stress, and pro-inflammatory cytokine expression, while promoting reparative macrophage reprogramming and endothelial migration. In diabetic wounds, a single application of Gel/aNEV accelerates wound closure and enhances angiogenesis, collagen remodeling, and tissue regeneration. Integrated transcriptomic-proteomic analyses further reveal coordinated changes in complement, inflammatory, redox, extracellular-matrix, and regenerative programs, supporting a multicomponent therapeutic model. Collectively, this study establishes an atlas-to-therapy framework that uses disease-associated neutrophil states to guide extracellular-vesicle engineering, integrating complement regulation, immune reprogramming, and biomaterial-assisted delivery for diabetic wound repair.