Mussel-inspired adhesive hydrogel reprograms osteoimmune niche for robust bone regeneration in complex defects

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Immunology

Background:

• Complex bone defects present challenges due to irregular geometry, micro-motion, and immune microenvironments.
• Ideal bone repair materials require strong interfacial integration and active regulation of the osteoimmune response.

Purpose of the Study:

• To develop an injectable, photo-curable hydrogel (DPG@MA) for enhanced bone regeneration.
• To achieve stable adhesion to irregular bone defects and modulate the immune microenvironment.

Main Methods:

• Developed a double-network hydrogel using mussel-inspired chemistry (DOPA-pectin conjugate) and gelatin methacryloyl (GelMA).
• Incorporated alendronate-loaded mesoporous silica nanoparticles (MA) for sustained release of silicon ions and alendronate.
• Evaluated hydrogel performance in rat calvarial and tibial defect models.

Main Results:

• The DPG@MA hydrogel demonstrated stable, conformal adhesion to irregular bone defects.
• Alendronate-loaded nanoparticles effectively steered macrophage polarization towards a pro-healing M2 phenotype.
• Significantly enhanced bone regeneration and osseointegration compared to the clinical standard Novabone® in vivo.

Conclusions:

• The DPG@MA hydrogel offers a promising strategy for treating complex bone defects by integrating interfacial adhesion, immunomodulation, and osteogenesis.
• This approach actively reshapes the immune microenvironment to promote bone healing.
• The developed material represents a novel therapeutic avenue for challenging bone repair scenarios.