Bionic trabecular titanium alloy scaffolds produced by selective laser melting enhancement of bone and vascular regeneration through Schwann cell-mediated mechanotransduction

Using selective laser melting, a metal three-dimensional (3D) printing technique, we developed bionic trabecular titanium alloy scaffolds with a micro–nano composite porous structure to address the limitations of traditional titanium implants. By integrating bionic design principles with advanced metal 3D printing strategies, these scaffolds mimic the trabecular network of cancellous bone, reducing elastic modulus (to ~4 GPa) and mitigating stress shielding. The bioprinted scaffolds exhibited enhanced surface properties that promoted Schwann cell (SC) adhesion, elongation, and spindle-like morphology, forming cellular networks along the microporous architecture. In contrast, SCs on solid titanium scaffolds displayed a flattened morphology with limited functionality. Transcriptomic analysis revealed that the scaffold’s micro–nano structure regulated SC behavior via the focal adhesion kinase-mitogen-activated protein kinase mechanotransduction pathway, enhancing the secretion of pro-osteogenic (e.g., platelet-derived growth factor with two A subunits) and pro-angiogenic (e.g., vascular endothelial growth factor) factors. Trabecular-like scaffold-conditioned medium significantly accelerated bone marrow mesenchymal stem cell proliferation, osteogenic differentiation, and endothelial cell angiogenesis, achieving a 36% higher healing rate compared to controls. While in vivo validation remains essential, our in vitro model isolates SC-driven mechanisms, avoiding systemic confounders. This study highlights the potential of 3D bioprinted scaffolds for personalized bone defect repair, offering a biomechanically and biologically optimized solution to enhance osseointegration.