Calcium‐Capturing Hydrogel with Self‐Reinforced Multi‐Dynamic Networks for Effective Periodontal Bone Regeneration in Three‐Dimension

Abstract Hydrogel scaffolds perform well for periodontal bone regeneration. However, due to lacking injectability, poor mechanical strength, and weak adhesive force, conventional hydrogels are difficult to adapt to irregular periodontal defects and are unable to maintain stability under occlusal force. Consequently, the current approaches still present significant challenges in achieving intact 3D periodontal bone regeneration. Herein, a calcium‐capturing self‐reinforcing hydrogel, composed of alendronate‐functionalized oxidized sodium alginate (OSA‐Alen), nano‐hydroxyapatite (HAP), and dopamine‐grafted gelatin (Gel‐DA), is prepared for periodontal bone regeneration. The Schiff‐base reaction endows the hydrogel with injectability, while dynamic coordination between OSA‐Alen and HAP confers the superior self‐healing ability of hydrogel and homogeneous distribution of HAP. Tissue adhesiveness from Gel‐DA enables hydrogel to maintain stability within the defect area. Furthermore, hydrogel self‐reinforces mechanically by calcium ion (Ca ²⁺ ) capturing, providing a supportive matrix for bone regeneration, and promoting osteogenesis by the Ca ²⁺ influx. Especially, via a rat periodontal bone defect model, in vivo examination displays significant bone regeneration in 3D directions (57.03% bone volume fraction is achieved) after being treated with the injectable hydrogel for eight weeks. Consequently, the calcium‐capturing hydrogel offers an alternative biomaterial and presents profound potential for the repair of irregular periodontal bone defects and peri‐implant bone loss in the near future.