Biofunctionalizing devitalized bone allografts through polymer-mediated short and long term growth factor delivery

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Regenerative Medicine

Background:

• Large-scale bone allografts have high failure rates due to poor incorporation and remodeling.
• Current methods lack controlled delivery of crucial growth factors.
• Improving allograft integration is vital for long-term success.

Purpose of the Study:

• To develop a method for temporally controlled delivery of growth factors from bone allografts.
• To enhance allograft incorporation and remodeling.
• To reduce allograft failure rates.

Main Methods:

• Coating long bone allografts with a micron-scale degradable polymer layer.
• Loading vascular endothelial growth factor (VEGF) for rapid release and bone morphogenetic protein-2 (BMP-2) for sustained release.
• Utilizing in vitro studies with human mesenchymal stem cells and in vivo studies in rat femoral defects.

Main Results:

• The polymer coating maintained the allograft's pore structure.
• Controlled release kinetics showed early VEGF release and sustained BMP-2 release.
• In vitro studies confirmed BMP-2 bioactivity.
• In vivo studies demonstrated robust bone formation in treated allografts.

Conclusions:

• A microscale polymer coating offers temporal control over growth factor delivery from bone allografts.
• This approach enhances allograft incorporation and remodeling, potentially reducing failure rates.
• The methodology shows promise for accelerating early healing stages after implantation.