Surface Properties and Cell Response to Biomimetic Interconnected Microchannel Pattern on Additively Manufactured Ti6Al4V Implants

The design of surface architecture plays a critical role in regulating the physicochemical and biological performance of titanium-based implants. In this study, biomimetic interconnected microchannel surface architecture was fabricated on Ti6Al4V via selective laser melting (SLM). The geometry was generated through an artificial intelligence (AI)-assisted design approach to create a reticulated, isotropic microchannel network with a nominal depth and width of 200 µm. Two surface architectures, Patterned (interconnected microgroove networks) and Hatching (directional scan-line features inherent to SLM), and their acid-etched counterparts (Patterned-A and Hatching-A) were evaluated to assess their influence on surface characteristics and biological performance. Surface roughness was significantly higher in the patterned groups compared to the hatching groups. SLM-manufactured samples demonstrated increased Vickers microhardness relative to a polished, conventionally manufactured Ti6Al4V control. Acid treatment enhanced hydrophilicity, and Hatching-A exhibiting the lowest contact angle. In simulated body fluid, CaP deposition was most pronounced on Hatching surfaces, whereas the control showed no apatite formation. In vitro studies using Saos-2 cells showed improved osteogenic responses on SLM surfaces, and the Hatching group exhibited the highest cell viability and ALP activity. The cells on acid-treated groups showed lower proliferation but higher intracellular Ca 2+ content. These results demonstrate that biomimetic interconnected surface architectures can be successfully fabricated via SLM. Nevertheless, early in vitro osteogenic activity was more influenced by SLM hatching features than by the designed microchannel pattern.