Biodegradable Mg²⁺-releasing piezoelectric scaffold for segmental bone defect repair

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Engineering

Background:

• Critical-sized bone defects, especially segmental ones, pose significant challenges in orthopedic regeneration.
• Current bone graft limitations include donor site morbidity, immune rejection, and inadequate mechanical/biological performance.

Purpose of the Study:

• To develop a biodegradable piezoelectric cryogel scaffold (PWH Gel) for enhanced bone regeneration.
• To investigate the scaffold's ability to promote healing in critical-sized bone defects via self-generated electrical potentials and ion release.

Main Methods:

• Fabrication of a PWH Gel scaffold using gelatin methacryloyl (GelMA) and piezoelectric whitlockite nanoparticles (PWH NP).
• In vitro assessment of scaffold effects on bone marrow mesenchymal stem cells (BMSCs) proliferation, migration, and osteogenic differentiation, including endothelial tube formation.
• In vivo implantation into a rat critical-size radial segmental defect model to evaluate bone regeneration efficacy.

Main Results:

• PWH Gel demonstrated enhanced BMSC proliferation, migration, and osteogenic differentiation in vitro.
• The scaffold facilitated endothelial tube formation and Piezo1-mediated cellular responses.
• In vivo, PWH Gel achieved complete bone bridging with significant improvements in bone volume, trabecular organization, and vascularization.

Conclusions:

• The PWH Gel scaffold provides a dynamic, self-powered microenvironment that actively promotes bone regeneration.
• This Mg2+-releasing piezoelectric cryogel represents a novel approach for reconstructing segmental bone defects.
• The study highlights a significant advancement in electroactive biomaterials for treating large skeletal injuries.