Self-fitting shape memory polymer foam inducing bone regeneration: A rabbit femoral defect study

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Critical-sized bone defects pose significant challenges in treatment.
• Current bone regeneration scaffolds require improvement in defect contour matching and ease of implantation.
• Advanced scaffold design is crucial for enhancing bone healing and integration.

Purpose of the Study:

• To develop and evaluate a polyurethane/hydroxyapatite-based shape memory polymer (SMP) foam as a scaffold for bone regeneration.
• To assess the minimally invasive delivery and self-fitting capabilities of the SMP foam in vivo.
• To investigate the efficacy of the SMP foam in promoting bone ingrowth, vascularization, and remodeling.

Main Methods:

• Fabrication of a polyurethane/hydroxyapatite-based SMP foam scaffold.
• In vivo evaluation of scaffold implantation, including minimally invasive delivery and self-fitting behavior.
• Micro-computed tomography (micro-CT) analysis to quantify bone ingrowth.
• Histological analysis to assess vascularization and bone remodeling.

Main Results:

• The SMP foam allowed for convenient, minimally invasive implantation in a compact shape.
• The scaffold demonstrated effective self-fitting to the bone defect boundaries upon in vivo shape recovery.
• Micro-CT revealed bone ingrowth initiated at the scaffold periphery, decreasing towards the center.
• Histological examination confirmed successful vascularization and bone remodeling within the defect area.

Conclusions:

• Polyurethane/hydroxyapatite SMP foam shows significant potential as an advanced scaffold for bone regeneration.
• The self-fitting and minimally invasive properties of the SMP foam facilitate effective treatment of bone defects.
• This biomaterial supports essential processes for bone healing, including ingrowth, vascularization, and remodeling.