Design and Performance Analysis of a Bionic Radially Gradient Irregular Bone Scaffold

Irregular porous scaffolds based on Voronoi tessellation have attracted growing interest in bone tissue engineering because their geometric heterogeneity more closely resembles native bone than conventional periodic lattices. However, current Voronoi scaffold designs remain largely limited to homogeneous or axially graded architectures, whereas radially graded irregular scaffolds for long-bone repair have been insufficiently explored. Here, nine biomimetic radially graded irregular scaffolds with a target porosity of 70% were developed by synergistically tailoring seed-point distribution (PG) and strut-diameter gradient (DG) within a Voronoi framework. Their geometric features, mechanical properties, mass transport behavior, and biofunctional performance were systematically evaluated through numerical analysis and experimental validation. The scaffolds exhibited elastic moduli of 4.09-7.29 GPa, yield strengths of 75.30-271.35 MPa, permeabilities of 1.93-2.71 × 10-8 m2, and cell adhesion rates of 2.93-9.31%. Seed-point distribution primarily governed permeability and cell adhesion, whereas strut-diameter grading had a stronger effect on mechanical behavior and mechano-regulated cell differentiation. Among all designs, the PG1-DG1 scaffold, featuring a radially decreasing porosity, exhibited the highest permeability (2.71 × 10-8 m2) and cell adhesion rate (9.31%) while maintaining a stress-transfer pattern more consistent with native long bone. These findings provide a rational design strategy for developing load-bearing biomimetic bone scaffolds with balanced mechanical and biological performance.