Study on the parametric design and mechanical permeability properties of radially graded biomimetic disordered skeletal scaffolds

To address the issues that existing bone scaffolds cannot accurately mimic the gradient disordered structure of natural bone, involve cumbersome design processes, and have complex porosity control, this study derived a gradient recurrence formula and designed a radial gradient structure to replicate the density transition pattern of natural bone. Through generative design by adjusting topological software parameters, a single-parameter control mechanism for prism thickness was established to achieve efficient porosity regulation, and a trabecular-like disordered interconnected pore network was constructed. Simulation results showed that the mechanical strength (4-25 MPa) and permeability (3.86 × 10^-8-14.75 × 10^-8 m²) of the scaffolds all fall within the physiological range of human bone tissue. At porosity levels of 44.4%-74.1%, the flow field and pressure environment were favorable for mass transfer. Then, using strontium- and magnesium-doped calcium silicate/biphasic calcium phosphate (Sr-Mg-CS/BCP) composite material and stereolithography printing technology, micron-scale scaffolds with precision and performance highly consistent with the design presets were successfully fabricated. The heterogeneous gradient pore biomimetic parametric modeling method proposed in this paper provides a crucial methodological foundation for the structural optimization of biomimetic bone scaffolds.