Surface Micro-Patterning of Titanium Alloy Using Multi-Pass Wire-Electrical Discharge Machining for Favorable Biocompatibility

Abstract Owing to outstanding specific strength and corrosion resistance, titanium alloys are often employed as biomedical implants. The development of an oxide layer over the Ti-6Al-4V alloy surface due to surface modification during the electrical discharge machining (EDM) technique can serve as a corrosion impediment and promote biocompatibility. Surface engineering was used in this work by fabricating micropatterns over Ti-6Al-4V surface employing wire-electrical discharge machining (WEDM) to explore the effects of surface topography, pattern types, and surface roughness on the corrosion resistance, surface wettability, and cell adhesion for enhanced biocompatibility. Samples with various micropatterned surface features and surface topography were produced by the WEDM process. The multipass surface finishing technique was used with a goal of targeted surface modification prior to micropatterning on target surfaces using microchannels and micropillars. The corrosion and surface wettability tests showed that the sample with microchannels using multipass surface finishing provided the highest water contact angle and the lowest corrosion rate under the simulated body fluid. It has been found that the multipass trimmed surface performed better than the single-pass conventional WEDM machined surface in terms of providing favorable corrosion and cell culture performances. The sample with the shallowest microchannels and highest wetting behavior displayed the highest number of attached cells, whereas bacterial adhesion decreased with the increase in microchannel depth. Finally, it has been demonstrated that the implant surface can be tailored by surface patterning using multipass WEDM process for improved biocompatibility.