Study Unveils Injectable Hydrogel For Bone Regeneration

A research team has developed an innovative injectable adhesive hydrogel for bone regeneration. This hydrogel utilizes harmless visible light to simultaneously achieve cross-linking and mineralization without the need for bone grafts. The research was recently published online in Biomaterials.

Existing injectable hydrogels face challenges such as difficulty in maintaining their shape within the body and limited adhesive strength. Moreover, traditional methods using bone grafts with adhesive materials often fail to achieve simultaneous "bone regeneration" and "adhesion."

The researchers have introduced a novel system that addresses these limitations. This new hydrogel system employs visible light—safe for the human body—to facilitate cross-linking, where the main components of the hydrogel bond and harden, and to simultaneously boost mineralization where bone-building minerals like calcium and phosphate form within the hydrogel.

The newly developed hydrogel precursor comprises alginate, RGD peptide-containing mussel adhesive protein, calcium ions, phosphonodiols, and a photoinitiator. The coacervate-based formulation, which is immiscible in water, ensures that the hydrogel retains its shape and position after injection into the body. Upon visible light irradiation, cross-linking occurs, and amorphous calcium phosphate, which functions as a bone graft material, is simultaneously formed. This eliminates the need for separate bone grafts or adhesives, enabling the hydrogel to provide both bone regeneration and adhesion.

In experiments using animal models with femoral bone defects, the hydrogel was successfully injected, adhered accurately, and effectively delivered components essential for bone regeneration.

Professor Cha commented, "The injectable hydrogel system for bone regeneration developed by our research team represents an innovative alternative to conventional complex treatments for bone diseases and will greatly advance bone tissue regeneration technology."

Reference: Yun, J., Woo, H. T., Lee, S., & Cha, H. J. (2025). Visible light-induced simultaneous bioactive amorphous calcium phosphate mineralization and in situ crosslinking of coacervate-based injectable underwater adhesive hydrogels for enhanced bone regeneration. Biomaterials, 315, 122948.