Immunomodulatory and dentinogenic potential of surface-engineered hesperetin-functionalized composite scaffolds for pulp-dentin regeneration

Maintaining dental pulp vitality and promoting dentin regeneration in inflamed environments requires biomaterials that not only support cell differentiation but also actively regulate immune signaling. Here, we present a bioinstructive, immunomodulatory nanofibrous platform composed of polycaprolactone and nano-hydroxyapatite (PCL/nHA), surface-engineered through alkaline hydrolysis (H-) to enhance hydrophilicity and loaded with the flavonoid hesperetin (+HT) for sustained bioactive release. Physicochemical analyses confirmed improved surface wettability, calcium ion release, and diffusion-driven hesperetin delivery, all without compromising the scaffold's structure. In vitro, the scaffolds facilitated the migration, proliferation, and odontogenic differentiation of human dental pulp cells, leading to a significant increase in mineralized matrix formation. Using lipopolysaccharide-stimulated macrophages and a 3D inflammatory pulp capping model, the scaffolds modulated immune responses by downregulating pro-inflammatory cytokines and upregulating pro-resolving mediators, while also promoting dentinogenic and angiogenic gene expression. In vivo, subcutaneous implantation demonstrated favorable host integration, reduced inflammatory infiltration, early M2-skewed macrophage polarization, and organized extracellular matrix formation. Overall, this study introduces a surface-engineered, flavonoid-releasing scaffold as a bioinstructive platform that combines immunomodulation and odontoblastic signaling, providing mechanistic insight for designing next-generation materials aimed at regenerating the dentin-pulp interface under inflammatory conditions.