Angle defines attachment: Switching the biological response to titanium interfaces by modifying the inclination angle during selective laser melting

© 2018 Developing patient-specific biomedical implants for clinical application requires the integration of material science, manufacturing engineering, and biology. As selective laser melted (SLM) metallic additive manufactured implants become common, a key, but overlooked design parameter is its inclination angle. In this study, we have fabricated Ti6Al4V implants at three different inclination angles (0, 45 and 90 degrees) reporting the relationship between cell attachment, surface topography and surface chemistry at each angle. During the SLM process, we show that as the inclination angles increase, there is a corresponding increase in the number of partially melted particles adhering to the surface, greatly affecting the surface topography, morphology, roughness, chemistry, and wettability of the implant. In order to validate the approach, the effect of surface properties on cell fate was determined. In each case, the overall viability of Chinese hamster ovarian cells (CHO) was found to be statistically indistinguishable; however, the number of spindle cells and their dimension were found to increase significantly at higher inclination angles. This work demonstrates a novel approach for combining SLM technology in manufacturing metallic biomedical implants and provides a novel insight in case of switching cell‑titanium interface by modifying one process parameter, inclination angle, during rapid prototyping process.