Integrated Experimental and Computational Analysis of SLM-Fabricated Ti6Al4V Octet-Truss Scaffolds for Bone Tissue...

This study investigates the fabrication, characterization, and computational analysis of a Ti6Al4V porous scaffold for bone tissue engineering (BTE). The main objective is to address the stress-shielding effect caused by the mismatch in the mechanical properties between the scaffold and surrounding bone. An octet-truss architecture was considered to design a highly porous scaffold (with 80.5% porosity) and fabricated using selective laser melting (SLM). The scaffold was then treated with post-processing chemical etching in oxalic acid to remove surface defects and tailor topography. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that etching effectively removed adhered unmelted powder particles and created a distinct micro-textured strut surface (with increased roughness) that is conducive to osseointegration. The etching process also uniformly thinned down the struts and resulted in 10% mass loss. A compression test gave the scaffold's compliance-corrected elastic moduli of 4.54 ± 0.18 GPa (pre-etching) and 3.53 ± 0.06 GPa (post-etching). These values closely match with the stiffness of human trabecular bone reported in the literature. The experimental modulus results were validated with a finite element model that predicted 4.188 GPa, which agrees well with the experiment. Furthermore, computational fluid dynamic simulations evaluated a permeability of 8 × 10^-9 m², consistent with transport in bone-like structures.