Optimized micro‐sized cell sphere‐matrix niche co‐aggregates promote efficient oral and craniomaxillofacial bone regeneration

Abstract Imitating natural developmental mechanisms represents a pivotal approach for tissue repair and functional reconstruction. Nevertheless, efficient strategies for promoting coupled angiogenic‐osteogenic regeneration and repairing bone defects across multiple sites in the oral and craniomaxillofacial regions are still needed. Guided by self‐assembly principles, we constructed three‐dimensional (3D) stem cell spheres from human exfoliated deciduous teeth (SHED spheres). These spheres were then integrated with decellularized dentin matrix particles (DDMPs) and gelatin methacryloyl (GelMA) hydrogel. This integration yielded a cell‐niche co‐aggregate (GelMA‐SHED sphere‐DDMPs) capable of reprogramming the microenvironment. In vitro, DDMPs significantly enhanced osteo/odontogenic gene expression and stimulated vascular endothelial growth factor (VEGF) secretion in SHED spheres. MicroRNA sequencing (miRNA‐seq) identified a significant reduction in miR‐34c‐5p within the co‐aggregates, and bioinformatic analysis predicted NOTCH1 as a potential target, implicating that miR‐34c‐5p downregulation may influence stem cell function via modulation of the Notch pathway. Subsequent validation confirmed that DDMPs regulated the angiogenic potential of SHED spheres through the miR‐34c‐5p/NOTCH1 axis. In cranial and periodontal defect models, the reparative efficacy of the co‐aggregate depended on miR‐34c‐5p , enabling stable retention of cell spheres and matrix particles, promoting coupled angiogenesis‐osteogenesis, and demonstrating favorable bone repair outcomes with biosafety. This study proposes an optimized regenerative strategy integrating development‐inspired design, microenvironment reconstitution, and miRNA‐mediated regulation, offering a novel theoretical and technical framework for functional bone regeneration in oral and craniomaxillofacial contexts.