Bioactive 3D-Printed valve scaffold promoting valvular regeneration via immunomodulation and endothelialization

The in vivo performance of tissue-engineered heart valves remains constrained by a persistent early failure triad at the blood-material interface, namely thrombosis, unresolved inflammation, and slow endothelialization. Here, a bioinstructive multilayer valve scaffold is engineered to address these interfacial barriers through spatially integrated structural and biological functions. The scaffold comprises a digitally programmable 3D-printed framework, a silk fibroin wrapping layer, and a hydrogel biointerface incorporating Arg-Gly-Asp/GelMA adhesive cues together with H₂S-releasing microgels. This layered design endows the construct with valve-relevant tensile properties while simultaneously programming the immune-endothelial microenvironment. The hydrogel biointerface promotes endothelial migration, proliferation, and angiogenic activity, whereas sustained H₂S delivery biases macrophages toward a pro-resolving M2-like phenotype and suppresses inflammatory activation. Transcriptomic analysis further reveals coordinated upregulation of endothelial programs related to endothelial repair, migration, and proliferation, accompanied by attenuation of stress- and inflammation-associated responses. In vivo, the scaffold mitigates thromboinflammatory reactions, shows preliminary anti-calcification performance, and supports endothelialization under blood-contacting conditions. Together, this work establishes a layered bioactive engineering approach that converts a passive 3D-printed structural scaffold into a regenerative, hemocompatible, and immunoregulatory biofunctional valve scaffold. This strategy offers a promising design principle for the further development of regenerative valve scaffolds.