A Three-in-One Strategy: Injectable Biomimetic Porous Hydrogels for Accelerating Bone Regeneration via...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Repairing irregular bone defects minimally invasively is challenging.
• Injectable hydrogels offer advantages over conventional scaffolds for bone defect repair.
• Previous work established a poly(lactide-co-glycolide) (PLGA) solution for potential bone grafting.

Purpose of the Study:

• To synthesize injectable MgO/MgCO3@PLGA (PMM) hydrogels for accelerated bone regeneration.
• To evaluate the PMM hydrogels' ability to form porous scaffolds in situ and adapt to irregular defects.
• To investigate the effect of controlled magnesium ion (Mg2+) release on bone healing.

Main Methods:

• Synthesis of MgO/MgCO3@PLGA (PMM) hydrogels.
• Assessment of injectability, in situ liquid-to-solid phase transition, and shape adaptability.
• Evaluation of sustainable Mg2+ release kinetics.
• In vitro studies on fibroblast proliferation, osteogenic differentiation, migration, and biomineralization.
• In vivo studies using rat calvarial defects with micro-CT and histological analysis.

Main Results:

• PMM hydrogels demonstrated excellent injectability and in situ transformation into porous scaffolds, conforming to irregular defects.
• Regulated Mg2+ release was achieved by adjusting the MgO and MgCO3 content.
• Mg2+ release significantly promoted fibroblast proliferation, osteogenic differentiation, migration, and biomineralization in vitro.
• In vivo, PMM hydrogels stimulated significant bone regeneration in rat calvarial defects, nearly doubling bone volume fraction compared to controls.
• The hydrogels gradually degraded while promoting bone healing.

Conclusions:

• Injectable PMM hydrogels effectively fill irregular bone defects and form porous scaffolds in situ.
• Controllable Mg2+ release from PMM hydrogels significantly enhances bone regeneration.
• These injectable biomimetic porous hydrogels (IBPHs) show great potential for minimally invasive repair of bone defects and clinical translation.