Additive manufactured graded porous zinc scaffolds based on sheet-Gyroid lattice for bone defect repair

Balancing degradation rate with mechanical stability represents a critical challenge in the development of biodegradable porous scaffolds. Functionally graded triply periodic minimal surface (TPMS) structures offer a novel strategy for designing biodegradable zinc (Zn) scaffolds for bone implants. Through gradient designs that mimic the anisotropic structures of natural bone, scaffold permeability, mechanical support, and biocompatibility can be harmonized, thereby satisfying the requirements of an ideal bone substitute. In this work, three uniform and six functionally graded porous Zn scaffolds were fabricated using laser powder bed fusion (L-PBF). Their mechanical properties, biodegradation behavior, and biocompatibility were systematically investigated. The results demonstrate that porous Zn scaffolds with the sheet-Gyroid unit cell exhibit uniform corrosion and maintain high mechanical integrity throughout dynamic biodegradation. At the same porosity, radially graded scaffolds exhibited larger deformability than longitudinally graded ones. Furthermore, the interconnected topological microenvironment provided by the sheet-Gyroid TPMS structure promotes cell adhesion and proliferation, indicating its potential to facilitate bone defect repair. • Graded porous Zn scaffold is fabricated based on sheet-Gyroid lattice. • Mechanical, biodegradation, and cells behavior of graded porous Zn scaffold are revealed. • Graded porous Zn scaffold maintains 90% mechanical integrity after 28 d of degradation. • Graded porous structure creates an interconnected topological microenvironment for cell.