3D-Printed-Cryogel-Impregnated Functionalized Scaffold Augments Bone Regeneration in Critical Tibia Fracture in Goat

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Critical-size bone defects pose significant challenges due to limited autograft availability.
• Developing effective bone graft substitutes is crucial for clinical applications.
• Current strategies often struggle to combine osteoconduction and osteoinduction effectively.

Purpose of the Study:

• To develop and evaluate a novel 3D-printed composite scaffold for critical-size bone defect repair.
• To investigate the synergistic effects of a polycaprolactone, polypropylene fumarate, and nano-hydroxyapatite (P-P-H) scaffold combined with a gelatin-nano-hydroxyapatite cryogel loaded with bone morphogenetic protein-2 (BMP-2) and zoledronic acid (GH+B+Z).

Main Methods:

• Fabrication of a 3D-printed P-P-H scaffold and a GH+B+Z cryogel.
• Implantation of the combined scaffold into critical-size goat tibia defects.
• Evaluation using X-ray radiography, micro-CT, histology, and immunohistochemistry after 4 months.

Main Results:

• The P-P-H scaffold demonstrated osteoconduction, while the GH+B+Z cryogel showed osteoinduction.
• Significant bone ingrowth was observed in the treatment group (45 ± 1.4% BV/TV) compared to the control group (10.5 ± 0.5% BV/TV).
• Histology confirmed substantial cell infiltration and matrix deposition, with significantly higher collagen I expression in the treatment group.

Conclusions:

• The 3D-printed P-P-H scaffold impregnated with GH+B+Z is a promising biomaterial for enhancing bone regeneration in critical-size defects.
• The combination of osteoconductive and osteoinductive properties facilitates comprehensive bone healing.
• This approach offers a viable alternative to autografts for treating severe bone trauma.