Photo-crosslinked integrated triphasic scaffolds with gradient composition and strength for osteochondral...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Osteochondral defects present significant repair challenges due to cartilage's avascular and aneural nature and the osteochondral unit's complex structure.
• Existing monophasic scaffolds inadequately address both cartilage and bone repair needs, while multiphasic scaffolds struggle with interfacial integration.

Purpose of the Study:

• To develop and evaluate a covalently bonded, triphasic methylpropenylated gelatin (GELMA) hydrogel scaffold for osteochondral defect repair.
• To assess the scaffold's ability to promote chondrogenesis, angiogenesis, and osteogenesis for integrated tissue regeneration.

Main Methods:

• Fabrication of a triphasic GELMA hydrogel scaffold with sequential covalent bonding.
• Incorporation of chondroitin sulfate in the upper layer to enhance chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).
• Introduction of gradient hydroxyapatite content in middle and lower layers to modulate mechanical strength and osteogenic/angiogenic induction.
• In vivo evaluation of the scaffold's repair performance in a rabbit knee joint osteochondral defect model.

Main Results:

• The triphasic scaffold demonstrated successful covalent bonding between layers, ensuring structural integrity.
• The scaffold promoted chondrogenic differentiation via chondroitin sulfate and enhanced angiogenic and osteogenic capabilities through gradient hydroxyapatite.
• In vivo studies showed accelerated regeneration of both cartilage and bone tissues in the rabbit model.

Conclusions:

• The developed triphasic integrated scaffold provides a novel and effective strategy for repairing osteochondral defects.
• This approach overcomes limitations of traditional scaffolds by enabling simultaneous and coordinated regeneration of cartilage and bone tissues.