Improved Bone Regeneration in Rabbit Bone Defects Using 3D Printed Composite Scaffolds Functionalized with...

Area of Science:

• Biomaterials Engineering
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Large bone defects pose significant treatment challenges, often limiting the use of traditional autografts.
• Patient-specific synthetic bone substitutes offer a promising alternative for bone regeneration.
• Controlling scaffold properties like porosity and rigidity is crucial for effective bone repair.

Purpose of the Study:

• To develop and evaluate novel 3D printed composite scaffolds as synthetic bone substitutes.
• To functionalize scaffolds with osteogenic factors to promote bone formation.
• To assess the *in vitro* biocompatibility and *in vivo* efficacy in critical size bone defects.

Main Methods:

• Fabrication of photocuring composite resins with poly(trimethylene carbonate) and bioactive ceramics.
• 3D printing of porous scaffolds and integration with macroporous cryogels.
• Functionalization of scaffolds with bone morphogenetic protein and zoledronic acid.
• Evaluation of biocompatibility *in vitro* and bone regeneration *in vivo* in rabbit tibia and cranial models.

Main Results:

• The 3D printed scaffolds demonstrated excellent biocompatibility *in vitro*.
• Functionalized scaffolds significantly enhanced bone formation and defect healing *in vivo*.
• Improved outcomes were observed in both critical size long bone and cranial defects in rabbit models.

Conclusions:

• Bioactive molecule-functionalized 3D printed porous composite scaffolds are effective synthetic bone substitutes.
• These scaffolds provide a conductive surface that promotes enhanced bone regeneration.
• The developed composites represent a promising next-generation solution for treating critical bone defects.