Comparison of Selective Laser Melted Commercially Pure Titanium Sheet-Based Triply Periodic Minimal Surfaces and Trabecular-Like Strut-Based Scaffolds for Tissue Engineering

This systematic comparison between sheet-based triply periodic minimal surfaces (TPMS) and strut-based ordered and disordered lattice topologies offers insights into parametric designs for tissue engineering scaffolds intended as implants. The study explores the effect of topology on compressive properties and in vitro osteoblastogenesis. TPMS-sheet gyroid and IWP, Voronoi tessellation with different sharpness, and cubic orthogonal lattices are studied. Disparities between the design intent and the as-manufactured scaffolds, intrinsic to selective laser processing, are considered to ensure that actual porosity and surface area per unit volume, two important factors in tissue engineering, are consistent across the set. Surface analysis reports the presence of microporosity created by partly sintered titanium particles. The TPMS topologies display a stretching-dominated deformation and the strut-based disordered ones a bending-dominated double-shear failure. Although the trabecular-like structures exhibit an enhanced compressive behavior when the designed topology is smoothed, they are more prone to printing imperfections with sharper finishes. The in vitro studies reveal that the trabecular sharp topology displays a faster proliferation rate, explained by concavity-driven cellular growth, but its smooth counterpart promotes a larger differentiation extent, outperforming TPMS, as it is aided by larger pore throats lined with microporosity at the scale of osteoblastic geometric features.