Comparative study on biodegradation and biocompatibility of multichannel calcium phosphate based bone substitutes

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Regenerative Medicine

Background:

• Bone defects pose significant challenges in orthopedics.
• Calcium phosphate ceramics are widely used as bone substitutes.
• Optimizing scaffold properties for enhanced bone regeneration is crucial.

Purpose of the Study:

• To fabricate and compare multichannel biphasic calcium phosphate (BCP) and beta-tricalcium phosphate (TCP) bone scaffolds.
• To evaluate their long-term biodegradation and bone regeneration potentials in vivo.

Main Methods:

• Multi-pass extrusion was used to fabricate cylindrical BCP and TCP scaffolds with interconnected channels.
• Scaffolds were characterized for morphology, composition, phase, porosity, and compressive strength.
• In vitro biocompatibility and ion release were assessed.
• In vivo biodegradation and bone regeneration were evaluated in a rabbit model over 1 week, 1 month, and 6 months using Micro-CT and histology.

Main Results:

• BCP scaffolds exhibited higher compressive strength than TCP scaffolds.
• TCP showed significantly higher calcium and phosphate ion release in simulated body fluid.
• Both scaffolds demonstrated excellent in vitro biocompatibility and promoted osteogenic marker expression.
• In vivo, both TCP and BCP were osteoconductive, supporting new bone formation.
• TCP scaffolds showed higher bone regeneration efficacy at 1 and 6 months post-implantation.
• Histological analysis confirmed faster degradation and better bone regeneration for TCP compared to BCP at 6 months.

Conclusions:

• Multichannel TCP and BCP scaffolds are osteoconductive and support bone regeneration.
• TCP exhibits faster biodegradation and superior bone regeneration potential compared to BCP in a rabbit model.
• TCP may be a more favorable material for bone defect applications requiring significant regeneration and resorption.