3D-printed composite scaffold with gradient structure and programmed biomolecule delivery to guide stem cell behavior...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Osteochondral defects pose a significant challenge in regenerative medicine.
• Developing scaffolds with both structural and biochemical cues to guide endogenous stem cell behavior is crucial for effective regeneration.
• Current strategies often struggle to simultaneously address cartilage and subchondral bone repair.

Purpose of the Study:

• To fabricate a composite scaffold (BE-PSA) with a gradient structure and programmed biomolecule delivery for osteochondral regeneration.
• To investigate the scaffold's ability to modulate bone marrow-derived mesenchymal stem cells (BMSCs) behavior for cartilage and subchondral bone repair.
• To evaluate the in vivo efficacy of the BE-PSA scaffold in a rabbit osteochondral defect model.

Main Methods:

• Fused deposition modeling (FDM) 3D printing was used to create a polycaprolactone (PCL) scaffold with distinct pore sizes for cartilage (200 μm) and bone (400 μm) regeneration.
• A composite scaffold (BE-PSA) was engineered by incorporating fast-degrading sodium alginate (SA) hydrogel for burst release of E7 peptide (enhancing BMSCs migration) and slow-degrading silk fibroin (SF) matrix for sustained release of B2A peptide (promoting dual-lineage differentiation).
• In vitro biocompatibility, BMSCs migration, and osteogenic/chondrogenic differentiation were assessed, followed by in vivo evaluation in a rabbit osteochondral defect model.

Main Results:

• The BE-PSA scaffold demonstrated good biocompatibility and effectively enhanced BMSCs migration and dual-lineage differentiation.
• The gradient structure and programmed release of peptides (E7 and B2A) synergistically promoted BMSCs behavior.
• In vivo studies showed significantly enhanced cartilage and subchondral bone regeneration in the rabbit osteochondral defect model using the BE-PSA scaffold.

Conclusions:

• The developed BE-PSA scaffold, integrating gradient architecture and sequential biomolecule delivery, shows significant potential for osteochondral regeneration by effectively guiding BMSCs.
• This study presents a promising biomaterial strategy for addressing complex osteochondral defects.
• The fabrication method offers a versatile approach for creating advanced tissue engineering scaffolds with tailored structural and biochemical properties.