Impact of 3D-Printed Tricalcium Phosphate Scaffold Polymorphism and Post-Processing Variations on Bone Regenerative...

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Regenerative Medicine

Background:

• Tricalcium phosphate (TCP) bioceramics, including α- and β-polymorphs, are used for 3D printed bone scaffolds.
• Hydrothermal immersion processing (HP) and sintering (S) are common post-printing treatments.
• Comparative in vivo data on osteogenic performance of HP-treated α-TCP versus S-treated β-TCP is lacking.

Purpose of the Study:

• To compare the in vivo osteogenic performance of α-TCP scaffolds treated with hydrothermal immersion processing (HP) against β-TCP scaffolds treated with sintering (S).
• To evaluate bone deposition and scaffold resorption at 3 and 12 weeks post-implantation.

Main Methods:

• Fabrication of α-TCP and β-TCP scaffolds using direct ink writing.
• Post-printing treatments: hydrothermal immersion processing for α-TCP (α-TCP/HP) and sintering for β-TCP (β-TCP/S).
• In vivo implantation in skeletally mature sheep, with evaluation at 3 and 12 weeks.

Main Results:

• No significant differences in bone deposition or scaffold resorption were observed at 3 weeks.
• At 12 weeks, β-TCP/S scaffolds showed significantly increased osteogenesis (p < 0.001) and scaffold resorption (p = 0.004) compared to α-TCP/HP.
• Sintered β-TCP demonstrated superior osteoconductivity and resorption over 12 weeks.

Conclusions:

• Post-print sintering of β-TCP enhances osteogenesis and resorption compared to hydrothermal immersion processing of α-TCP.
• β-TCP scaffolds processed by sintering show promising potential for bone regeneration applications.
• The choice of TCP polymorph and post-printing treatment significantly impacts scaffold performance in vivo.