Hierarchical silk/silk-ZnSr-β-TCP scaffolds for osteochondral tissue engineering: Mechanical performance and effects on bacterial adhesion

The needs of osteochondral (OC) defects restoration that simultaneously include adequate mechanical behavior and prevention of bacterial biofilm formation, without impairing local tissue integration, is of great importance when developing novel biomaterials for OC tissue applications¹. Hierarchical scaffolds consisting of a cartilage-like layer interconnected to an underlying subchondral bone-like layer emerged as advanced technological solutions that can better mimic the native OC tissue². This study is focused on the mechanical properties evaluation and bacterial biofilm formation of hierarchical scaffolds consisting of a horseradish peroxidase (HRP)-crosslinked silk fibroin (SF) layer (HRP-SF) integrated into an adjacent ZnSr-doped β-tricalcium phosphate (β-TCP) layer (HRP-SF/ZnSr-β-TCP)³.The combined compression-shear loading properties were performed in wet conditions, and the bacterial adherence and biofilm formation on the scaffolds surface was evaluated using Escherichia coli (E. coli, Gram negative) and Staphylococcus aureus (S. aureus, Gram positive). The hierarchical scaffolds presented appropriate ability to support tension and shear loading for OC tissue. Furthermore, the scaffolds have shown limited bacterial adhesion and biofilm formation on the structures surface. The superior mechanical performance together with the non-effective bacterial growth and adhesion on the hierarchical scaffolds, have potential to provide new treatments for OC tissue repair.