Influence of Porosity Gradient Distribution on Mechanical and Biological Properties of Gyroid-Based Zn-2Mg Scaffolds for Bone Tissue Engineering

To address the insufficient matching between high strength and low elastic modulus in traditional metal bone scaffolds and the issue of secondary surgical removal, this study used degradable zinc magnesium alloy as the material to study the relationship between porosity gradient distribution and mechanical and biological properties of Gyroid porous bone scaffolds. We established three groups of scaffolds with different porosity gradient distribution, including uniform, axial gradient, and radial gradient. Numerical simulation experiments were conducted for axial compression. The simulation results show that compared to uniform and axial gradients, radial gradient scaffolds have the highest Young's modulus and exhibit exceptional load-bearing capacity. The results of sample compression experiments show that under the same (average) porosity, the elastic modulus of uniform porous scaffolds and radial gradient porous scaffolds was not significantly different, but reverse radial gradient scaffolds exhibited superior yield strength relative to uniform porous scaffolds. Moreover, forward radial gradient scaffold extracts showed lower toxicity on the in vitro proliferation of mouse calvarial pre-osteoblast cells. By designing a forward radial gradient Gyroid porous bone scaffold, it is expected to obtain a biodegradable Zn-2Mg porous bone scaffold with excellent mechanical and biological properties.