Dual-bionic titanium scaffolds based on a gyroid-sheet structure and BaTiO₃ piezoelectric coating: a synergistic approach for bone defect repair

Abstract Three-dimensional-printed porous titanium alloy implants have shown significant potential for addressing large segmental bone defects in weight-bearing applications. Nevertheless, existing limitations, particularly stress concentration within porous structures and biologically inert surfaces, often result in suboptimal bone ingrowth and reconstruction failure. Therefore, optimizing the scaffold structure to homogenize the stress distribution and endowing the implant with osteogenic capabilities are critical approaches to improve the success rate of bone defect reconstruction. In this context, a dual-bionic titanium scaffold combining a triply periodic minimal surface (TPMS) architecture for mechanical optimization with a barium titanate (BaTiO 3 ) piezoelectric coating to enhance electromechanical conversion was constructed. Structural and functional characterization validated the improved mechanical performance and efficient electromechanical response of the scaffold. In vitro and in vivo studies further revealed that BaTiO 3 coated TPMS scaffolds promoted osteogenesis and bone remodeling by activating the focal adhesion kinase and PI3K/AKT signaling pathways through electromechanical stimulation during defect repair. This biohybrid design paradigm provides a promising solution for load-bearing bone regeneration through simultaneous mechanical optimization and electromechanical microenvironment regulation.