Research on 3D-printed scaffolds with microstructure bio-inspired optimization for orbital bone defect repair

Mechanical compatibility is a major challenge in designing orbital bone scaffolds, which involving material selection, structural design and fabrication processes. In this study, a novel impact model database containing essential components involved in tissue engineering repair of orbital fracture was established for finite element analysis (FEA). The mechanical compatibility between various pattern-designed scaffold and the orbital bone defect site was tested to raise the optimized square pattern filled scaffold for the subsequent study. Based on the optimized structure, 3D printed bone scaffolds with different β-TCP contents were fabricated. It was confirmed that the composite scaffold containing 30% β-TCP and 70% polycaprolactone (PCL@30TCP) demonstrated significantly enhanced hydrophilicity, mechanical strength, water absorption, and accelerated degradation relative to other groups (p < 0.05). In vitro evaluations confirmed the significant advantages in cytocompatibility and osteogenic activity of PCL@30TCP scaffold (p < 0.05). Furthermore, rabbit orbital defect repair experiments demonstrated that the 3D-printed PCL@30TCP scaffold markedly promoted osteogenesis at the defect site through three synergistic mechanisms: enhancing neo-bone formation and maturation, guiding tissue growth into the interior structure of scaffold, and obviously upregulating bone morphogenetic protein 2 (BMP-2) and osteocalcin (OCN) expression (p < 0.05). Importantly, comprehensive biosafety assessments validated the clinical applicability of the PCL@30TCP scaffold. These findings indicate that the square-patterned PCL@30TCP 3D-printed scaffold exhibits exceptional osteogenic performance both in vitro and in vivo, demonstrating clinical potential for orbital bone defect repair.