The multi-scale porous and hydrophilic 3D printed polycaprolactone/ silk fibroin/ β-tricalcium phosphate bone scaffolds effect on femoral defect repair.

In response to the clinical challenges of bone defect repair, the 3D printed scaffold inspired by the natural structure enables personalized repair of complex defects, reducing infection risks and promoting bone regeneration. Herein, we have developed a functionalized gradient bone repair polycaprolactone (PCL) based scaffold. A PCL/SF/β-TCP-NaOH (PST-NaOH) scaffold with a multi-scale pore structure (inner layer 450 μm/outer layer 130 μm) was constructed using layered 3D printing technology by combining β-tricalcium phosphate (β-TCP) and silk fibroin (SF). Its mechanical properties match the needs of spongy bone. NaOH surface treatment further optimizes the interfacial activity of the scaffold, which also improved the hydrophilicity and controllable degradation characteristics. The results showed that the scaffold promoted bone regeneration through a synergistic mechanism. On one hand, the multi-scale pores guided bone tissue growth. On the other hand, hydrophilic surface modification and SF/β-TCP complex system enhanced the activity of MC3T3-E1. Animal experiments showed that after scaffold implantation, the mineralization and maturity of new bone matrix in the bone defect area was significantly promoted, breaking through the limitations of insufficient regeneration of pure PCL material. This study provided innovative solutions with both structural adaptability and biological functionality for the clinical treatment of critical bone defects.